- Aug 2018
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postelectrophoresis
Used to increase DNA of interest. This is done by analyzing the separation patterns on the gel with the use of fluorescently labeled DNA sequencing fragments. Cutting out the desired band and then amplifying the DNA for further use.
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small subunit ribosomal RNA (SSU rRNA)
An RNA component of the ribosome and is vital for making proteins.
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symbiosis
The relationship between two organisms that interact with one another.
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denaturing gradient gel electrophoresis (DGGE)
Denaturing Gradient Gel Electrophoresis (DGGE) has been used, along with yeast cultures, to analyze saliva samples of 24 adults to study the bacteria present. This study showed ample variation of bacteria among individuals. The conclusion obtained from this experiment was that there is a lack of association between yeasts and bacterial DGGE fingerprint clusters in saliva, implying a significant ecological specificity.
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In this study, we evaluated the effectiveness of HRMas a tool to rapidly and precisely genotype monotypic Symbiodinium populations using the internal transcribed spacer, region 2, ribosomal DNA (ITS2 rDNA).
This study (experiment) wanted to identify the effectiveness of high-resolution melting for the genotype (genetic makeup) of the Symbiodinium. Symbiodinium are single-celled algae that can be found in the endoderm (innermost layer of cells or tissue of an embryo in early development) of tropical cnidarians such as corals, sea anemones, and jellyfish.
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High-resolution melting
A technique that detects mutations, and differences in DNA samples. HRM has been used to target various microbial communities on tadpole intestines and feces. In this study, HRS targeted a short amplicon (piece of DNA or RNA that is the source of amplification or replication events) of the 16S rRNA gene, which was the sequence being tested. Along with the HRM, gel electrophoreses and DNA sequencing were also used in order to study the results more closely. All three methods revealed several types of bacteria living in a tadpole's intestines and feces.
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he mean number of alleles per locus ranged between 3.0 (Dominican Republic) and 3.1 (Haiti),
The Palms from the Dominican Republic and Haiti were found to have similar average allele loci counts, but the Haitian ones have more on average.
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(AMOVA)
The purpose of this experiment was to analyze population genetics. To achieve this, the researchers used AMOVA, or analysis of molecular variance, to detect population differentiation using molecular markers. The program was set to 10,000 permutations and they were able to obtain estimates of genetic differentiation and mean number of migrants with the GenAIEx v. 6.5 program.
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genetic variation
Differences in the genetic makeup within populations over time.
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Total genomic DNA of fresh leaves of a single individual of C. argentata was also isolated with the DNeasy Mini Plant kit. This DNA sample was subsequently used to obtain microsatellite loci that were developed by the Georgia Genomics Facility at the University of Georgia (Athens, Georgia, USA).
This experiment isolated the genome of an individual C. argentata sample using the same method described in the previous experiment (DNeasy). The DNA sample obtained from this group was then taken to the Georgia Genomics Facility at the University of Georgia to develop microsatellite loci which are single sequence repeats that allows researchers to see any variability in the genome of this specific plant compared to the others. The researchers then used an Illumina HiSeq 2000 to see the microsatellite markers. The process through which they obtained these microsatellite loci is not described in the paper; however, the significance of this step when comparing different samples of DNA is described in the video below: https://www.youtube.com/watch?v=9bEAJYnVVBA
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native/endemic species
Plants are imperative to the world’s ecosystem, nevertheless, many plant species are largely disappearing. Cycads, palm-like plants, are one of these endangered plants that has been around for more than 300 years. Studies are being conducted on ways to save these plants and the implications its extinction may have.
Read more here: https://news.mongabay.com/2017/05/saving-the-most-endangered-plants-in-the-world/
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genetic diversity and erosion
Gene diversity in a species of plants is imperative to its survival when its environment is either degrading or constantly changing. If genetic erosion occurs, the fitness of this species decreases and it is at a much higher risk of extinction which is the case for Pulsatilla patens, a plant species from East Central Europe.
Read more about it: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0151730
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hydrological changes
Differences within the movement and quality of water.
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They also can reveal patterns of genetic diversity of species with very narrow distribution that in many cases are in the verge of extinction (Allendorf and Luikart, 2007; Oleas et al., 2013). Caribbean Island palms have been the focus of conservation initiatives that include red-listing [sensu IUCN (2014) by Zona et al. (2007) and Peguero et al. (2015b)]; species inventories (Moya López and Leiva Sánchez, 2000; Leiva Sánchez, 2006); conservation genetic studies (Rodríguez-Peña et al., 2014a, 2014b); field surveys and conservation assessments (Henderson et al., 1990; Leiva Sánchez, 2008; Peguero et al., 2011, 2015a)
This research demonstrates how we can deal with issues that face threatened species through a series of field surveys, conservation assessments, and molecular research.
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Distribution of Coccothrinax jimenezii showing the location of the only two known populations of this species in Haiti (Gonaïves) and Dominican Republic (Lago Enriquillo).
Due to the small population of Coccothrinax jimenezii within Haiti and Dominican Republic, conservation efforts have been maximized to prevent extinction.
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molecular phylogenetics
A branch of phylogeny that uses molecular and statistical techniques to determine hereditary differences within organisms.
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genetic differentiation
Genetic differentiation is the variation between allele frequency in populations that have been isolated.
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Fig. 7 On this figure of electrosensory pathways in the gymnotiform fish (modified from Carr and Maler, 1986), we have labeled regions where the proposed computations for high-frequency electrolocation might be implemented.
The author used results from video, electric images, and BEM simulations to depict the electrosensory pathways in the fish and where the fish has organs with receptors that are able to sense electric fields. By knowing the location of these electroreceptors, the author is able to determine where the organism is able to conduct electrolocation.
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Finally, knowing object distance is a prerequisite (or corequisite) in the model for deconfounding size, impedance and shape, so these features would first appear in the torus and higher areas. Although this proposal is not yet based on quantitative simulation or modeling, we believe it may be a useful working hypothesis for interpreting and further exploring parts of the electrosensory nervous system.
Here, the authors are hypothesizing that the EOD pattern incorporated into electrosensory nervous system of the electric fish uses the information of size, shape, and distance of the objects in an algorithm to process and relay information to the electric fish brain.
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quantifying
To organize into a numerical format.
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phylogenetic relationships.
Associations between the evolutionary history of a group of organisms where"poly" means many and "genetic" refers to origin.
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interpolating
The act of inserting one object or substance into another. For this study, the slices from the EOD records taken through time are put into the slices from EOD records taken through space to create a map that shows the potential and amplitude of the EOD.
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However, this hypothesis has not been fully tested because the electrosensory input has not yet been well described during exploratory behaviors in freely moving fish.
It is difficult to examine the exploratory behavior of a free moving fish because the data typically used do not accurately describe the fish's behavior. The EOD geometry and the electric images are complex because they can change based on the fish's movement. The movement changes the source of the electric organs and in laboratory setting the behaviors that use electroreception are hard to maintain. The difficulty experienced in a control laboratory setting to examine the certain behaviors, makes collecting and analyzing data of a free moving fish rather challenging.
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we have focused on reconstructing quantitatively the entire pattern of currents resulting from the fish’s discharge and environment.
The authors here talk about the premise of their experiment and how they want to take all the data that the team has collected visually and through pattern tracking and turn it into data that has numbers. That is why in the chart that follows there is system mapping for EOD of both "wave" and "pulse" fish.
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Electric discharges (EODs) generated by a specialized electric organ (EO) within the body cause electric current to flow in the surrounding water.
An exhibit dedicated to electric fish has opened at Smithsonian's National Zoo in Washington, D.C. The exhibit includes a life-sized electric eel model and lights powered by eel-generated electricity to enable visitors to see and understand how these creatures work.
For more information on this exhibit, visit https://nationalzoo.si.edu/news/new-electric-fishes-exhibit-opens-smithsonians-national-zoo
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gymnotiform
An order of freshwater bony fish that can be identified by a long body, anal fins, nocturnal behavior, and the ability to generate electric fields for communication, navigation, and defense. The eel, for example, is a well-known gymnotiform.
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the generation and detection of electric currents
This paper goes in-depth on how different kinds of fish use their electrical currents to detect different objects and sense their location. They also use electrical discharge as a way of exposing who they are, similar to how humans can recognize other people are by looking at their faces.
For more information into another use for these fish's electrical discharge visit, https://www.eurekalert.org/pub_releases/2011-04/wuis-jic041511.php
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electrolocation
This is when animals use electric fields in their surroundings to detect their own location in space. Only certain species with electroreceptors can do this, consider how bats perform echolocation with their vibration detections.
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C. Parmesan, G. Yohe, Nature 421, 37–42 (2003).
Identifying effects of climate change on recent biological trends is difficult because non-climatic changes greatly influence local, short-term biological changes. Parmesan and Yohe study the differences between climatic and non-climatic effects on over 1700 species. A diagnostic indicator of temporary, geographic shifts was found with confidence for 279 species.
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M. H. Williamson, Biological Invasions (Chapman & Hall, 1996).
A collection of invasive species and the damages they can cause, summarized by an invasive species expert. The focus of the text is on approach to biological control and releasing genetically modified organisms.
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Our results demonstrate that evolution on ecological time scales can increase the speed of advance in spreading populations, and markedly so in the most patchy landscapes.
NGSS Disciplinary Core Ideas, Learning Standard 2: Ecosystems: Interactions, Energy, and Dynamics
The study looks into how evolution of one species impacts the ecosystem around it, thereby impacting the organisms around it. This goes back to the idea that organisms living in the same area interact and can determine the survival or decreased success of the other. The rapidly spreading species competes with other organisms in the area for resources, effecting the success of its surroundings.
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Fig. 3. Genotypes and traits at the invasion fronts.
Figure 3 shows the initial and final genotype compositions as well as trait changes among the different conditions (A. continuous, B. gap size of four times the mean dispersal rate, C. gap size of eight times the dispersal rate, and D. gap size of 12 times the dispersal rate). The central pie chart found in each of the four graphs shows the equal frequency of genotypes in the founding population, while the other pie charts are used to represent the genotypic make-up of the top 10 leading individuals after 6 generations of spreading within the different conditions. The placement of the pie charts is based on rankings of three traits: the competitive ability of the plant (dominance of the plant in ways that do not directly affect it's ability to spread offspring), dispersal (the average distance of the farthest dispersed seed from the plant it was dispersed from), and the height of the plant.
These values show that even as the gap size increases, the trait values hardly increased at all. Similarly, as can be seen by the color of the pinwheels, the genotype composition change between the different gap sizes was rather consistent. The only outlier is the continuous condition that has random trait values and genotype compositions.
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These evolutionary changes reflect the combined effects of selection and drift.
NGSS Disciplinary Core Ideas, Learning standard 4: Biological Evolution: Unity and Diversity.
The evolution of the spreading species is evident in Figure 3 as it shows the changes in allele frequency due to the changing environmental conditions (larger gaps).
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Fig. 2. Farthest distance colonized in each generation.
As the distance between populations increased, the distance seeds were dispersed followed a similar increase for evolving populations, regardless of the distance between populations. Non-evolving populations dispersed seeds shorter distances based on how big the gap was between populations.
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We initiated each replicate invasion in the leftmost pot of the array by sowing equal fractions of 14
In the first experiment, the authors simulated invasion by planting 14 genotypes on one side of the pot array. The plants were allowed to proceed for several generations to follow evolution in A. thaliana. Habitat patchiness was tested by putting space between the pots at varying distances.
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The spread velocity of cane toads
In recent years, traps for adult toads and nets for tadpoles were set in order to limit this invasive population in Australia. While successful in slowing spread in the West, expansion of cane toad territory in northern Australia is only expanding.
Read more in ABC Science: http://www.abc.net.au/science/articles/2003/02/28/793049.htm
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anthropogenic barriers
Refers to something that was caused by humans. Anthropogenic barriers could include roads, agricultural areas, or cities. These barriers can reduce the ability for species to migrate.
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competitive ability
In the case of this paper, referring to the capacity of individuals within a population to establish themselves in an area. Unlike fitness, this has less to do with surviving to seed, and more to do with being dominant in a space shared with other populations.
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evolving populations spread 11% farther than nonevolving populations
NGSS Disciplinary Core Ideas, Learning standard 4: Biological Evolution: Unity and Diversity.
LS4.C: Adaptations Evolution leads to more fit and adapted species for specific environments.
In this study, this phenomenon leads to the superior expansive and competitive ability of the evolving population over the non-evolving population.
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landscape patchiness
As human activities have cleared habitats to extract resources or establish agricultural land or housing, habitats have become concentrated in smaller patches with unfavorable land in between. This is also known as habitat fragmentation, and can impede the migration of species to more favorable habitats.
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evolutionary dynamics
As species move to new places with different environmental conditions, species evolve. Which traits are favored and how trait and gene frequencies change are aspects of evolutionary dynamics. For example, plant traits including height and dispersal change as plants spread to new areas.
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migrations
The spreading of, in this case, a plant species due to its dispersal of seeds. The plant itself does not move to new locations like when animals migrate, but instead, it refers to the spreading distribution of the plant species.
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biological invasions
Events in which a new organism is introduced to the environment, then grows and reproduces to the point that it becomes common in the new environment. These events are often associated with harming the native species, but are also how species adapt to changing conditions.
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pathogens
Any foreign organism that can cause disease. Common pathogens are viruses, bacteria, and fungi.
Bumble bee pathogens are organisms that cause detrimental effects in bumble bees.
Since the mountainous regions occupied by bumble bees lack pathogens, the pathogens do not influence the evolution of mountainous bumble bees.
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Although populations of long-tongued bees are undergoing widespread decline (1, 3), shifts in foraging strategies may allow alpine bumble bees to cope with environmental change.
Long-tongued bee populations are declining due to climate change. However, bumble bees that change what flowers they choose to forage may be better at surviving the changes to their habitat.
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phenotypes
The physical expression of an organisms genetic makeup. Everything we physically observe in an organism is due to the expression of their genes (their genetic information).
The phenotype of tongue length in bumble bees is highlighted in this study. Bumble bees featuring different genes that express tongue length display a variation in tongue length.
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Fig. 2. Changing bumble bee community composition, bumble bee tongue length distributions, and tube depth distributions of visited flowers over time. (A and B) Bumble bee community composition. (C and D) Bumble bee tongue length. (E and F) Flower tube depth distribution. Bombus species abundance in alpine communities is indicated by the proportion of total foragers (15). Species are ordered by increasing tongue length [in (A), species’ names follow (18)]. Bimodality of the density functions (15) indicates that bumble bee communities contain two predominant phenotypes, short-tongued and long-tongued [(C) and (D)]. (E) and (F) show the tube depth density functions for flowers visited by, respectively, B. balteatus and B. sylvicola in the Front Range [Mount Evans and Niwot Ridge (15)]. For tongue length [(C) and (D)] and tube depth [(E) and (F)], representative density functions for simulated communities (15) are shown.
These results suggest that bumble bee tongue lengths are decreasing and corolla tube lengths are also decreasing in response to climate change.
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On Pennsylvania Mountain, alpine bumble bees forage over hundreds of meters to provision their nests (28). To ask how warming has affected floral resources at this scale, we measured PFD of six bumble bee host plants from 1977–1980 and 2012–2014 in five habitats along a 400-m altitudinal span (table S5). Land surface area decreases with altitude above tree line in the Rocky Mountains (29), declining by more than an order of magnitude on Pennsylvania Mountain, where 58% of habitable terrain is found below 3800 m and only 4% above 3938 m on the summit (Fig. 3Aand table S5). Because bumble bees forage across the 400-m altitudinal range (28), we evaluated the temporal change in flower production at this landscape scale. For each habitat, we multiplied PFD (flowers per square meter) within sampling plots by surface area (square meters) to estimate of total flower production (15)
From 2012-2014, researchers analyzed the change of flower production of six bumble bee host plants over time at a altitude of 400m. This is where the bumble bees most commonly forage. The flower abundance was measured as flowers per square meter across five different habitats. It was then compared to data from 1977-1984 to determine change over time.
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Climate records from Niwot Ridge show warming summer minimum temperatures over the past 56 years (27).We see similar changes on Mount Evans (R2 = 0.383, t1,52 = 5.68, P < 0.0001) and Pennsylvania Mountain (R2 = 0.341, t1,52 = 5.20, P < 0.0001) (fig. S3, A and B), where summer minimums have increased ~2°C since 1960. We used a nonlinear model to characterize the relationship between peak flower density (PFD; flowers per square meter) and summer minimum temperature.
Over the past 56 years, climate change has caused summer temperatures at Niwot Ridge, Mount Evans, and Pennsylvania Mountain to rise. To understand the relationship between summer temperatures and flower density, four bumble bee host species were analyzed for change in average flower density between 1977 and 2014.
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Optimal foraging theory
A theoretical model used to indicate how an animal will look for food. Factors that influence how an animal will forage for food depend on the costs of energy or risk gathering the food compared to the energy gain benefit from the food.
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In six species that historically provided 88% of floral resources for B. balteatus and B. sylvicola (18), the change in flower depth over time varied among species (F6,13 = 9.42, P = 0.0004). Species that now have shallower flowers received few (<10%) bumble bee visits historically (fig. S2A). On Pennsylvania Mountain and Niwot Ridge, short-tubed flowers show no systematic increase in abundance [coefficient of determination (R2) = 0.227, t1,4 = 1.21, P= 0.294; R2 = 0.0004, t1,9 = –0.62, P = 0.952, respectively) (fig. S2, B and C), suggesting that recent changes in floral trait distributions are insufficient to drive tongue length adaptation in bumble bees.
Flowers typically pollinated by B. balteatus and B. sylvicola did not have a significant increase in pollinators during the recent history. This indicates that floral trait distribution are not what is causing the decrease in bee tongue lengths. This rejects the hypothesis that there is a direct correlation between flower depth and tongue length.
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Levin’s niche breadth
A constant used to compare the relative size of an organism's foraging area. Larger numbers indicate a larger foraging range.
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foraging breadth
The range or obtainable food sources for an organism.
For the alpine bumble bees, this includes sources of nectar and nest building materials.
This paper highlights how the foraging breadth of native bees is decreasing due to increasing competition from immigrant species.
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With increasing competition from immigrant species, foraging breadth of resident bees should contract (19, 20). Yet alpine bumble bee host choice shows the opposite trend.
For the native alpine bee species, access to food has not decreased. This rejects the hypothesis that competition between foreign and native bee species for resources decreases the native bee’s range of accessible food.
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subalpine congeners
Species of bees from subalpine climates, that are within the same genus.
Climate change has warmed the alpine climate, making it's temperature closer to a subalpine climate, and increasing the range of the subalpine bee species.
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(i) decreasing body size, (ii) coevolution with floral traits, (iii) competition from subalpine invaders, and (iv) diminishing floral resources.
The author listed four possible processes responsible for the tongue length changes in the bees studied:
1) Decreased body size over time has correlated to a shorter tongue - The authors compared the body size measurements with the tongue length measurements over time.
2) Coevolution between the flowers and bees - The tube depth of the flowers were measured and compared to the tongue length of the bees over time.
3) Competition from other bees in the same region affected tongue length - The authors compared other bee species to the bees studied and determine which species had the advantage and if these advantaged affected the other species.
4) Diminishing floral resources - The authors analyzed the effects of lower amounts of flowers due to increased temperatures on the foraging habits of bees. They then concluded if this could have impacted tongue length.
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host plants
Plants that are in a mutualistic relationship with the pollinators.
In this paper, host plants are involved in a mutualistic relationship between themselves and bumble bees.
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B. sylvicola
A species of bumble bee known as the forest bumblebee. It is native to North America and is found in open alpine grasslands near mountains.
Bombus sylvicola feeds on plants such as lupines, fireweeds, and groundsels, which are all plants found in alpine habitats.
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Bombus balteatus
A species of bumble bee known as the golden belted bumblebee. It lives in high altitude alpine habitats and has a long tongue that is more than two-thirds of its body size.
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coevolution
Evolution is the change in alleles (genetic information) in a population over time. Coevolution is when two species influence the evolution of each other.
Coevolution is generally observed when a long lasting mutualistic relationship between two species exists.
As plants and bumble bees evolved alongside each other, each acted as a selective pressure for the other, altering their evolutionary paths so that each is better suited to live alongside the other.
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mismatch between shorter-tongued bees and the longer-tubed plants they once pollinated.
As this research has presented, due to rising temperatures, bees have began to favor generalist foraging. A recent news story shows how honey bees have started pollinating blueberry plants, which are not very easily accessible for other bees.
Read more: https://www.sciencenews.org/article/honeybees-fumble-their-way-blueberry-pollination
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morphology
The study of an organism's physical characteristics and their function.
In a mutualistic relationship between species, scientists are able to match the morphological traits that directly affect the symbiotic relationship (morphological matching).
This paper highlights the morphological matching between the corolla length of flowers and the tongue length of bumble bees.
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Mutualisms evolve through the matching of functional traits between partners
Mutualistic relationships between bees and flowers have resulted in both to coevolve with one another. Bees are essential to the pollination of flowers, because of this recent headlines about their possible endangerment could be catastrophic.
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generalist foraging,
Foraging is the act of an organism searching for food. Generalist foraging is when an organism forages for a wide variety of food, or in other words is more adept at foraging for whatever is more convenient. Bees showing generalist foraging will eat from a wider range of flowers.
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climate
The common weather patterns of a given area.
As climate change occurs, the prevailing weather patterns of all areas are viable to change as well.
Changing climate of bumble bee habitats are causing changes in pollination requirements of bumble bees to flowers.
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corolla tubes
The cylindrical opening created by the petals of a flower that leads to the reproductive organs of a given plant. The tube also leads to rewards for pollinates, such as nectar.
The corolla tube is what a bumble bee sticks its tongue down to acquire nectar. The longer the corolla tube, the longer the tongue of a bumble bee must be to access the nectar held within the tube.
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pollinators
A living organism capable of spreading pollen from one flower to another.
Generally pollinators are insects or birds. The pollinator highlighted in this paper is the bumble bee.
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biodiversity
A measurement of the number of species in an ecosystem.
The greater the number of different species in a given ecosystem, the greater the biodiversity measurement of said ecosystem.
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agriculture
The practices used in farming to produce goods, such as crops and animals.
Agriculturally based mutualisms consist of symbiotic relationships between organisms and cultivated organisms.
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mutualisms
A relationship between two different organisms where both species benefit from that relationship.
The symbiotic relationship highlighted in this paper is the one between long-tongued bumble bees and plants. The bumble bees benefit the plants by pollinating them as they move from plant to plant and the plants benefit the bumble bees by giving them nourishment.
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We observed a statistically significant reduction in JHAMT transcript levels in the CA of starved adult female mosquitoes (Fig. 2B).
The authors found that when mosquitoes had less sucrose to feed off of there were fewer enzymes to convert the JH acids into the juvenile hormones. These JHAMT (enzymes) are important for the final steps of JH biosynthetic pathway. If the mosquitoes drank water with 20% sucrose their JHAMT levels were significantly higher. Observations can be seen in Figure 2B.
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high performance liquid chromatography
High performance liquid chromatography (HPLC) is a technique commonly used in analytical chemistry to help separate, identify and quantify components in an organic mixture.
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Lipid assays
Lipid assays include utilizing synthetic lipids to construct a lipid bilayer similar to the cell membrane. Lipid assay kits may be used to measure concentrations of lipid mixtures in comparison to membrane proteins in a cell membrane.
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Our results reveal that starvation decreased JH synthesis via a decrease in insulin signaling in the CA. Starvation-induced up regulation of the insulin receptor increased CA insulin sensitivity and might “prime” the gland to respond rapidly to increases in insulin levels after feeding resumption. During this response to starvation the synthetic potential of the CA remained unaffected, and the gland rapidly and efficiently responded to insulin stimulation by increasing JH synthesis to rates similar to those of CA from non-starved females.
The results of the experiment indicate that starving a mosquito ultimately decreases the production of JH due to a decrease in insulin signaling in the CA, which is located near an insect's brain. By being starved, the insulin receptor in the CA became more sensitive, so when a mosquito was fed, insulin levels rapidly increased due to this new sensitivity.
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Changes in JH synthesis in female adult A. aegypti mosquito are very dynamic and nutrition-dependent
Release of juvenile hormone is determined by their blood meal, and their meal determines whether glucose will be absorbed to their muscle and fat cells.
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JH and insulin regulate reproductive output in mosquitoes; both hormones are involved in a complex regulatory network, in which they influence each other and in which the mosquito's nutritional status is a crucial determinant of the network's output.
The hypothesis is saying the mosquitoes' nutrition has an effect on "insulin sensitivity" and "juvenile hormone synthesis." Insulin is a hormone that works with the amount of glucose (sugar) in blood. A juvenile hormone is a hormone in insects that work with maturation and reproduction. So the researchers are saying that the amount of nutrition (food) the mosquitoes eat will determine the amount of these two hormones, insulin and juvenile, are produced.
Since the researchers hypothesize that how much the mosquitoes eat determines how much insulin and juvenile hormones work, this means how much insects reproduce is also affected. So the researchers are saying if the insects eat enough, they will reproduce with better conditions than if they were not eating enough. This is because the hormones that control reproduction are controlled by the insects' nutrition.
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juvenile hormone
A chemical signal that regulates larva development and metamorphosis in insects.
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journals.biologists.com journals.biologists.com
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we measured the position and bearing of the fish swimming at a constant velocity with no acceleration; the position and bearing at time zero was then converted into Cartesian coordinates using the range of the center acoustic beam as a reference distance.
Certain variables in the frame of these barracuda, as they were being detected, was used through complicated physics and mathematics to calculate their stride lengths.
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Parafilm
Primarily used in laboratories. It is commonly used for sealing or protecting vessels (such as flasks or cuvettes). It is a ductile, malleable, waterproof, odorless, translucent, and cohesive thermoplastic.
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ensuring stimulation of the white muscle tissue
Ensuring the white muscle tissue were stimulated by the electric pulse to contract, tighten.
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time from initial lure strike to landing was minimized and never exceeded 15 min.
The time it took to hook a fish, reel it in, and brought on board was never more than 15 minutes.
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they would incur an increased maintenance cost (Karasov, 1986) for repairing damaged tissue
They would injure themselves too much, potentially leading to death.
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Dorado showed relatively poor performance, both in absolute and size-corrected speeds,
Dorado (also known as mahi mahi or dolphinfish) were overall the slowest, showing that they can't depend much on speed to catch their prey, rather more on their ability to maneuver to catch them.
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cruising specialist
A type of fish that swim around and look for their prey, which are widely dispersed. They also have a stiff body with minimal drag when they swim. Sharks and salmon are also cruise specialists.
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red muscle
Type of skeletal muscle in a fish; slow-twitch muscle on the outer sides of a fish.
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ecomorphology
The study of the relationship between the ecological role of an individual and its morphological (i.e. structure/form) adaptations.
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relatively high speed estimated for little tunny may partly be due to their higher muscle temperature
Though the authors used statistical tests to determine that there was no statistically significant difference between the muscle temperatures of the fishes observed, so it shouldn't greatly affect the results, the fact still remains that it still has some effect.
Perhaps the reason why the little tunny had the highest size-corrected maximum speed is due to muscles -which were warmed than the other fish. As a result, its muscles had a higher speed measured than if its temperature had been even closer the the other fishes' muscle temperatures.
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Although it is likely that early work overestimated swimming speeds, speeds higher than those predicted based on the twitch contraction methods might theoretically be possible if fish were able to change their mode of swimming to accommodate for the otherwise lack of increase in tail beat frequency
The maximum frequency at which a fish can move its tail is limited by the twitch contraction time of the white lateral muscle. The maximum swimming speed is then predictable if the distance moved forwards on completion of each oscillation (the stride) is known.
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sailfish appears to be the fastest
Sailfish are the fastest of the four fish observed, but that's because they're the largest. When the variable of fish size is put aside (size-corrected performance), sailfish are actually the slowest and the smallest fish, little tunny is the fastest.
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x-axis is percentage of total length
The x-axis shows where along the length of each fish the contraction times were collected from, starting from the head (0%) to the tail (100%).
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on average 1.25 times faster swimming speed.
Regardless from which part of the body the lowest contraction time (highest speed) was found, this time was used as the maximum swimming speed of that fish species. These higher measures for maximum swimming speed can be calculated about 1.25 times faster than the normal swimming speed of each fish.
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P<0.001
In statistics, 'P' is the p-value. The p-value is the probability that the null hypothesis is true, and if it's below .05 that usually means the null hypothesis (there is no correlation between the two variables being observed) is rejected as not true.
In the case of this section of the paper, a statistical test was run to see if the mean temperatures of the fishes (taken from the muscles being observed) were significantly different from each other. It was found that the probability of this was so low (below .05), they were not significantly different.
This is important because it implies that all the muscles of all the fish had close enough temperatures to each other that the researchers wouldn't have to worry about slightly different muscle temperatures making the contraction times collected in each fish faster or slower in relation to each other.
Basically, they checked that the muscle temperatures in each fish were close enough to each other that the variable temperature would be (close enough) to being a "constant" in all the tested subjects in the experiment.
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forces needed to reach a certain swimming speed
This refers primarily to effects of strong and weak water currents, as discussed in the last few annotations.
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Here we investigated maximum speed of sailfish, and three other large marine
Sailfish, barracuda, little tunny, and dorado are four marine predatory fish species known for their extremely high swimming speeds.
The researchers decided to reconsider how accurate the previously predicted estimates of each of those species' maximum swimming speeds truly is, hypothesizing that they may be over-estimations.
They did this by using a different method than that used to make the estimates they're investigating. Their method was to measure the time it takes for every contraction of swimming muscle (that doesn't use oxygen) when it twitches.
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Billfishes are considered to be among the fastest swimmers in the oceans.
Billfish have long bills (elongated upper jaw), which allows them to cut through water, and aerodynamic bodies so they can swim in speeds of up to 120 kilometers per hour. Billfish include sailfish, swordfish, and marlin.
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Alopex lagopus
Binomial nomenclature for the arctic fox. They are native to the arctic regions in the northern hemisphere, and are commonly found in the arctic tundra biome. They are carnivorous with a common diet of birds, hares and insects in the Aleutian islands.
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- May 2018
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Zabierowski SE, Herlyn M. Melanoma stem cells: the dark seed of melanoma. Cancer Lett. 2008;26:2890–93.
This study investigated the hierarchy of characteristic genes of melanomas with the goal of developing new therapeutic treatments.
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Spinella F, Rosano L, Di Castro V, Decandia S, Nicotra MR, Natali PG, Bagnato A. Endothelin-1 and endothelin-3 promote invasive behavior via hypoxia-inducible factor-1alpha in human melanoma cells. Cancer Res. 2007; 67:1725–34.
The study investigated the interactions between hypoxia, an oxygen deficiency, and the ET axis, or the ET receptors, in primary melanoma cell lines and metastasized melanoma cell lines. Metastasized means that the tumor beyond the tissue initially affected by the tumor.
The study found that ET-1, ET-3 and the ET(B)R react with HIF-1alpha-dependent molecules to promote melanoma invasion of tissues. The HIF-1alpha is the hypoxia-inducible factor-1alpha, a transcriptional factor that induces a signaling by growth factor receptors and hypoxia.
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Shackleton M, Quintana E, Fearon ER, Morrison SJ. Heterogeneity in cancer: cancer stem cells versus clonal evolution. Cell. 2009; 138:822–9.
This study focused on targeting genes present in malignant cancer cells to develop novel therapeutic treatments for cancers.
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Schatton T, Murphy GF, Frank NY, Yamaura K, Waaga-Gasser AM, Gasser M, Zhan Q, Jordan S, Duncan LM, Weishaupt C, et al. Identification of cells initiating human melanomas. Nature. 2008; 451:345–9.
This study was designed to investigate tumor promoting cells, which could have therapeutic benefits if they are targeted with a specific treatment. The targeted cells accumulate in advanced cancers.
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Pla P, Larue L. Involvement of endothelin receptors in normal and pathological development of neural crest cells. Int J Dev Biol. 2003; 47:315–25.
This study examined how mutations that affect neural crest development pathways affect neural crest cells. It also examines how endothelin receptors act during cell development, movement, and differentiation.
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Larue L, Beermann F. Cutaneous melanoma in genetically modified animals. Pigment Cell Res. 2007; 20:485–97.
This study examined the effects of NRAS gene mutations in mouse models and how these mutations affect cancer development. The conclusion reached was that somatic mutations in the NRAS gene are risk factors of primary melanoma in mouse models and in children.
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Garcia RJ, Ittah A, Mirabal S, Figueroa J, Lopez L, Glick AB, Kos L. Endothelin 3 induces skin pigmentation in a keratin-driven inducible mouse model. J Invest Dermatol. 2008; 128:131–42.
This experiment was conducted at Florida International University as well.
The results indicate the Endothelin 3 originating outside of the nucleus affects melanocyte precursors and differentiated melanocytes. It causes a phenotype similar to dermal melanocytosis to be developed.
Dermal melanocytosis is a blue-grey pigmentation of the skin that usually occurs in newborn humans.
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Bittner M, Meltzer P, Chen Y, Jiang Y, Seftor E, Hendrix M, Radmacher M, Simon R, Yakhini Z, Ben-Dor A, et al. Molecular classification of cutaneous malignant melanoma by gene expression profiling. Nature. 2000; 406:536–40.
The authors examined melanoma development in a series of samples with the use of mathematical techniques. A subset of melanomas was discovered with the use of these samples and mathematical models. Many of the genes used to identify this subset are regulated differently in aggressive melanomas that have metastasized.
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Bellahcene A, Castronovo V, Ogbureke KU, Fisher LW, Fedarko NS. Small integrin-binding ligand N-linked glycoproteins (SIBLINGs): multifunctional proteins in cancer. Nat Rev Cancer. 2008; 8:212–26.
The researchers investigated the role of a group of glycophosphoproteins known as SIBLINGs, or small integrin-binding ligand N-linked glycoproteins, in cancer development. The results indicated that the SIBLINGs could be used in therapy development, diagnosing cancers, or predicting prognoses.
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Bagnato A, Rosano L, Spinella F, Di Castro V, Tecce R, Natali PG. Endothelin B receptor blockade inhibits dynamics of cell interactions and communications in melanoma cell progression. Cancer Res. 2004;64:1436–43. [PubMed]
Bagnato investigates the agonists of the endothelin B receptor (ET(B)R), endothelin-1 (ET-1) and ET-3 and the role that they play in tumorigenesis.
Bagnato states that (ET(B)R) is a marker for tumor progression. This study supported the role of ET-1 and ET-3 to impede the usual interactions between hosts and tumors.
The ligands also promote development of cutaneous melanoma. Melanoma is a cancer in melanin-producing cells. Cutaneous melanoma is melanoma that occurs on skin.
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Genetic studies have also suggested that Sox10and Ednrb do not interact during murine melanocyte development (Hakami et al., 2006).
Sox10 is expressed in melanoblasts, which are the precursors of melanocytes, that do not contain Ednrb. Ednrb is expressed in embryos that do not contain Sox10. Therefore, Sox10 expression does not depend on the expression of Ednrb.
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hypermorphic
Hypermorphic refers to mutations in the gene that result in an increase of gene expression. Therefore, hypermorphic alleles result in hyper-pigmentation as described in the paper.
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Disease stabilization without unanticipated adverse effects, was observed in 6 of 35 patients at 12 weeks of treatment and in 5 of 35 patients at 24 weeks suggesting that Ednrb antagonists may prove useful in metastatic disease stabilization (Kefford et al., 2007) particularly when used in combination with other anticancer drugs (Berger et al., 2006; Kefford et al., 2007,).
Disease stabilization is important in treating diseases because cancers can often become malignant, meaning they can spread to other parts of the body and cause other cancers. Therefore, this drug, together with other drugs, can prevent secondary cancers in other parts of the body (metastasis).
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Bosentan has also been tested in a phase II study as a single therapeutic agent for stage IV metastatic melanoma.
Antagonist "Bosentan" was tested in a study and showed to stabilize the disease. This means that the disease is neither progressing nor regressing in development.
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Recent studies using the Ednrb antagonist bonsentan suggest that the use of Ednrb antagonists may prove useful for the treatment of melanoma.
Ednrb antagonists could potentially be used for the treatment of melanoma. Read more: www.theoncologist.alphamedpress.org/content/20/10/1121.full.pdf
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This inhibitor was also capable of increasing cell death in culture and reducing human melanoma tumor growth in nude mice (Lahav et al., 1999). A subsequent study found that BQ788 is most effective at inducing apoptosis in metastatic melanoma cells (Lahav et al., 2004).
The antagonist (inhibitor molecule that prevents the expression of Ednrb) also killed cells that were infected with the disease. This is another answer to the research question "If endothelin signaling were to be inhibited, would this serve as a new treatment for specific melanomas?".
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Ednrb small interfering RNA (siRNA) and the Ednrb antagonist BQ788 are able to block endothelin-induced effects that can lead to melanoma progression (Spinella et al., 2007). Other studies using the same antagonist have reported an inhibition of melanoma growth (Baganato et al., 2004; Lahav et al., 1999, 2004,)
This result answers the question raised in the editors introduction: "If endothelin signaling were to be inhibited, would this serve as a new treatment for specific melanomas?". Yes, research showed that interfering RNAs (RNA molecules that prevent the expression of a gene) and a specific antagonist (another interfering molecule) can prevent endothelin signal pathways from leading to melanoma.
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prostaglandin
Prostaglandin are a group of fatty acids that act as hormones in the body. For example, during pregnancy the contractions are stimulated by a prostaglandin.
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High VEGF levels are in turn associated with poor prognosis in human melanoma tumors (Giatromanolaki et al., 2003).
Studies show that there is a high expression of VEGF in human melanoma tumors, indicating that VEGF can serve as a marker for melanoma prognosis. Moreover, tumors with a high vascular density (VD) were also associated with poor prognosis.
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hypoxic
Hypoxia refers to the condition in the body where there is a deprivation of oxygen to the tissues.
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heterotypic
Heterotypic refers things that are different in form or type. So, heterotypic cell to cell adhesion is adhesion between two different types of cells.
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catenin
Catenin is a type of protein in the human body that is in charge of regulation and coordination of cell to cell adhesion.
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Moreover, in situ melanomas appeared in adult skin grafts, while invasive melanomas developed in newborn skin grafts indicating that the susceptibility of skin to environmental tumor promoters is dependent on age (Berking et al., 2004).
Exposure to ultraviolet (UV) radiation is a risk factor for the development of melanoma. Researchers have shown that people who sunburned in childhood are at a greater risk of developing melanoma than are people who sunburned in adulthood. This study suggests that age is associated with the susceptibility of skin to environmental carcinogens.
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synergistic effects
Synergistic effects refers to an effect where the combination of both is greater than the sum of the individual parts. So the whole is greater than its individual parts.
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irradiation
Irradiation refers to treating something with radiation, in this case UV light.
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in human skin grafted to severe combined immunodeficiency disease mice
In this experiment, skin from a human was grafted onto mice with depressed immune systems. This means a piece of human skin was transplanted onto mice whose immune systems could not protect them from diseases.
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Edn1 secretion from keratinocytes increases after exposure to UV radiation (Ahn et al., 1998; Imokawa et al., 1992, 1997; Jamal and Schneider, 2002) and it was found to have an antiapoptotic effect on melanocytes (Kadekaro et al., 2005).
Exposure to UV radiation, such as from the sun, caused melanocytes to continue developing. This is because the programmed cell death (apoptosis) function was compromised in the presence of UV radiation. As a result, Edn1 (one type of endothelin peptide) had an increase in production and caused pigmentation to increase.
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aberrant
Aberrant refers to something that differs from the accepted standard, so it could be something that is abnormal. For example aberrant Edn3 expression is that expression which differs from the norm.
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Although Ednrb downregulation has been reported in some human melanoma cell lines (Eberle et al., 1999), other studies found Ednrb to be upregulated in most melanoma cell lines (Bittner et al., 2000; Ross et al., 2000). Ednrb expression was found to be enhanced in melanoma metastases compared to primary tumors and thus it has been proposed as a marker for melanoma progression (Demunter et al., 2001).
Even though there are some contradictions to the research, generally, if there is more Ednrb activity (up-regulation) then there are more cancerous cells (melanomas). Because of this, observing the expression of the Ednrb gene can help researchers follow the progression of the disease.
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melanomagenesis
Melanomagenesis refers to the development of melanoma through the multistep process of genetic mutations.
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The placement of oncogenes under the control of melanocyte specific promoters has led to the development of melanoma in mice (Bradl et al., 1991; Broome-Powell et al., 1999; Chin et al., 1997; Kelsall and Mintz, 1998; Klein-Szanto et al., 1991, 1994; Powell et al., 1995; Wong and Chin, 2000; reviewed in Larue and Beermann, 2007), indicating that it is possible for melanoma to arise from a committed melanocyte precursor (reviewed in Grichnik, 2008). Recently, the finding that melanoma cell fractions transplanted into NOD/SCID IL2Rγnull mice are highly tumorigenic irrespective of whether or not they express the stem cell marker CD133, suggests that melanoma does not appear to follow the cancer stem cell model (Shackleton et al., 2009).
This result contradicts the cancer cell model because the cell can be programmed to be cancerous by placing an oncogene (a mutated proto-oncogene that causes uncontrolled cell division) near a promoter (a region on DNA that allows for gene expression to occur via trascription/translation). Therefore, the cell does not have to follow the differentiation path to become cancerous.
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The stem cell marker-positive cells identified in melanomas were capable of self-renewal and of differentiating into various cell lineages. Furthermore, these cells were more tumorigenic when transplanted into immunocompromised NOD/SCID mice than their stem cell marker-negative counterparts.
Because cells that contained this "marker-positive" were able to differentiate into many different types of cells, the original idea of linear progression of melanoma may not be useful in monitoring the disease. This is because the cancer can arise at different steps and differentiation points.
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The treatment of mouse NC cells carrying Kitl mutations with Edn3
In this study, the cells from the neural crest of mice that carried the specific mutation Kitl were treated with endothelin 3.
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Melanoblast numbers increased in the presence of either factor; however, treatment with both Edn3 and Kitl led to a significant increase in the number of melanoblasts compared to either factor alon
The opposite of the previous statement is also true: If both of the signaling pathways are present, then there will be an increase of melanoblasts. This is because these pathways stimulate survival and cell division of melanoblasts.
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In mouse NC cultures, the lack of either Edn3 or Kitl resulted in nearly a complete loss of melanoblasts.
This occurred because Edn3 works with Kitl (a signaling pathway) in order to stimulate the survival and cell division of melanoblasts (the cell stage that comes before the melanocyte). Therefore, the lack of these signaling pathways prevented melanoblats from forming.
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non-cutaneous
Cutaneous refers to something in the body relating to the skin. Therefore, non-cutaneous refers to something that does not have to do with the skin. For example non-cutaneous melanocytes would be those that grow in areas not relating the the skin.
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melanoblasts
Melanoblasts are precursors to melanocytes. So, they are the cells that come before the melanocytes.
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murine NC cultures
This study was done on the neural crests taken from murine cultures, so it is also an in vitro study of the effects of endothelin on the development on melanocytes but this time on a different species.
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This increase in cell numbers in the treated cultures could not be accounted for solely by a proliferative effect, pointing to a possible role for Edn3 in the survival of melanoblasts from the NC (Opdecamp et al., 1998).
Mutations in genes that code for Edn3 result in deficiencies in melanocytes. Edn3 serves as a stimulator of melanoblast proliferation and differentiation. When melanoblasts differentiate, they become melanocytes.
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sciatic nerve
The sciatic nerve is a long nerve in the body that runs from the bottom of the spine to the back of the leg and above the knee joint.
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Edn3 was most effective in promoting the long-term propagation of glia-melanocyte precursor cells as opposed to the other precursors (Real et al., 2006).
Researchers have shown that individual melanocytes produce multipotent cells that are able to regenerate during consecutive subcloning. This indicates that the multipotent cells display stem cell qualities. Edn3 encourages the maintenance of the multipotent cells. Moreover, Edn3 stimulates the proliferation of melanoblasts, which are the precursors of melanocytes.
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transdifferentiate
Transdifferentiation is when a cell, other than a stem cell, differentiates into a different type of cell.
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induces
Induce refers to the production or promoting of something. So if the Edn3 induces proliferation, it brings about proliferation.
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cells treated with Edn3 were found to proliferate for two weeks without producing pigment (Lahav et al., 1996).
Cells proliferate in the presence of Edn3. The cells that are produced are melanoblasts, which subsequently become melanocytes.
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contact inhibition
Contact inhibition is a process in the body that regulates cell growth. For example, when the cells come in contact with each other, its a sign that its time to stop growing, hence the name contact inhibition.
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Treatment of quail NC cultures with Edn3
The study described here consisted of treating quail (type of bird) neural crest cultures with Edn3. This study was in vitro, meaning the embryonic neural crest was removed and treated outside of the organism. This study showed the role that Edn3 plays in development as stated in the paper.
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in vitro
In vitro refers to a study that took place outside of the living organism, so in a test tube or culture dish, etc. The opposite would be an in vivo experiment that takes pace inside the organism.
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chemotactic
A chemotactic response is a response to a chemical stimulus that results in the movement of the body.
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dorsolateral
A dorsolateral pathway is one that is on the dorsal and lateral surfaces. Lateral refers to something away from the mid line of the body and dorsal refers to the upper back of an animal.
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melanoblasts
Melanoblasts are cells that become melanocytes. They proliferate and pile up in the migrating stage area. Then they become part of developing hair follicles, where they differentiate into melanocytes.
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Ednrb signaling affects melanocyte development prior to or at E12.5.
Mice with white coats (the piebald lethal phenotype) and mice with the inserted gene (lacZ) had a decreased amount of melanoblasts (cells that come before melanocytes) by day 12.5 in embryonic development. Therefore, Ednrb signaling must be occurring at or around this time in development.
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endogenous
Endogenous refers to something that originates from within an organism, or something that has an internal cause or origin. A promoter that is endogenous originates from within.
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Edn1 and Edn3 have also been implicated in hyperpigmentation pathological conditions in mice
Mice with dark, black coats were found to have hyper-pigmentation and a correlation with melanoma (tumor of the cells that produce pigment).
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aganglionosis
Aganglionosis is characteristic in megacolon and it means that there are no ganglia present. Ganglia, or ganglion cells, are a type of nerve cell responsible for moving food in the colon. As a result, their absence can lead to constipation.
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megacolon
Megacolon is an abnormal dilation of the colon. So, the colon widens and oftentimes the movement of the bowels can stop.
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Mutations or deletions of the mouse genes Ednrb and Edn3 result in the piebald lethal (sl) and lethal spotting (ls) phenotypes, respectively (Fig. 1). Mice carrying the piebald lethal mutation are mostly white, except for spotted regions in the head and rump. They die as juveniles
Mice with white coats have a deadly mutation that kills the mice while they are very young. The phenotype (the physical expression from the gene) is called "piebald lethal". Mice with spotted coats have a similar outcome to mice with white coats and their phenotype is called "lethal spotting" or hypo-pigmentation (meaning lacking pigment).
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Edn3 was found to play a major role during the development of melanocytes from neural crest (NC) cell precursors.
Researchers were able to determine that Edn3 plays a vital role in melanocyte development by studying the pigmentation of mice coats. The coats vary in pigment depending on the mutation on gene Ednrb.
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melanogenic
Melanin is the skin-darkening pigment produced in melanocytes. Therefore, melanogenic refers to a melanocytes ability to produce melanin. If a substance is melanogenic it stimulates a cell to produce melanin.
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mitogenic
Mitogenic refers to stimulating a cell to start dividing through mitosis. For example, a mitogen is a chemical that stimulates division in a cell, so it has mitogenic properties.
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It was first identified as a potent vasopressor derived from vascular endothelial cells (Yanagisawa et al., 1988).
Researchers isolated Edn1 to determine its function. Edn1 was shown to be responsible for an increase in blood pressure. Expression of the gene was controlled by factors that affect blood vessels, suggesting that there is a cardiovascular control system.
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kinases
A kinase is an enzyme that catalyzes the transfer of a phosphate group from ATP to a desired molecule. For example, a nonreceptor tyrosine kinase is in charge of transferring a phosphate group from ATP to tyrosine in proteins. Tyrosine is one of the 20 amino acids found in proteins.
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adenyl cyclase
An enzyme that is in charge of catalyzing the formation of cyclic AMP into ATP. To catalyze means to increase the rate of the reaction, so this enzymes speeds up the rate at which ATP is produced from cyclic AMP. ATP is the energy molecule of the body.
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phospholipase
Phospholipase is an enzyme that hydrolyzes, or breaks down, phospholipids into fatty acids. There are four types of these enzymes: A, B, C, and D.
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cardiomyocytes
Cardiomyocytes are cardiac muscle cells. For example, the heart is made up of cardiac muscle, and thus these cells.
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heterotrimetic
Refers to a macromolecule that is made up of at least three subunits where one of the subunits of the molecule differs from the other two. A G-Protein is an example, because it is made up of an alpha, beta, and gamma subunits.
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G-protein coupled
G-Protein Coupled Receptors are located in the cell membrane of eukaryotes. Their function is to receive signals from the outside, that will then produce a cellular response. There are many different types of these receptors talked about in the paper.
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paracrine factors
Paracrine Factors are produced by certain cells in order to communicate with adjacent cells around them. They are a form of signaling between cells to alter the behavior of cells around them.
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Antagonists
A receptor antagonist functions by blocking a biological response by binding to the receptor that would have previously stimulated this response. For example, for the endothilin receptor type b (Ednrb) discussed in this paper, an antagonist would bind to it and block the response that would have been produced originally. So they function as biological blockers.
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metastases
Metastases refers to when a malignant tumor grows at a site away from the original site. For example, if you say that lung cancer metastasized to the liver it means that the lung cancer is now also found in the liver. It developed at a site away from the original, in this case from the lungs to the liver.
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differentiation
In cells, differentiation refers to a cell that is less specialized becoming more specialized. This occurs during development, so melanocyte differentiation is when developing cells specialize into melanocytes.
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precursors
A precursor is something that happens before something else. So in terms of biology it refers to a cell or tissue that will give rise to another cell or tissue that is more specialized, or mature. In this paper, a melanocyte precursors are cells that came before and will differentiate into melanocytes.
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neural crest (NC)
The neural crest is an embryonic structure in vertebrates that gives rise to many types of cells, primarily cells of the peripheral nervous system. So during embryonic development, the neural crest differentiates and migrates to give rise to specialized cell types. They also give rise to melanocytes which will be further discussed in the paper.
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melanocytes
Melanocytes are skin cells that produce the pigment melanin. Melanin is the skin darkening pigment that is known for protecting the skin from harmful rays.
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Endothelin (Edn)
Endothelin is a vasoconstrictive peptide produced in endothelial cells. Vasoconstriction means that these peptides constrict blood vessels, increasing blood pressure as a result. These peptides are composed of 21 amino acids and there are three types: endothelin 1, endothelin 2, and endothelin 3.
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- Apr 2018
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graminoid
A plant with a grass-like physical structure and long blade-like leaves.
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zooplankton
Small, sometimes microscopic, animal-like organisms that exist in bodies of water. Can sometimes be made up of the larvae or immature forms of larger animals.
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arachnid
An invertebrate animal in the class Arachnida that includes spiders and scorpions, in this experiment the species observed was Cybaeus reticulates.
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The introduction of predators to islands provides an opportunity to explore the indirect effects of predators on vegetation. Introduced predators commonly have devastating direct effects on their prey
In the paper by M. Williamson, islands are subjected to introduced predators and the environment was monitored. Clusters of islands are ideal for demonstrating top down trophic cascades because similar ecosystems may be differently impacted by a single variable (with or without the top predator) and the insular ecosystems prevent the spread of the predator. The procedure of the two different predator locations allows for accurate monitoring of the different island ecosystems.
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trophic cascades
An ecological effect caused by the addition or removal of predators with changes to both the populations of predators and prey. The trophic cascade effect can either be top-down (predator to prey) or down-up (prey to predator). In a simplified food chain, if there is an increase (or decrease) in top predators then there would be a decrease (or increase) in herbivore prey and an increase (or decrease) in plant prey communities.
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- Mar 2018
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The two known populations of this species were included in our study, and we sampled 18–30 individuals per population (Table 1). All of the individuals (18) from the Dominican Republic population were included in the analyses. Leaf material was fast dried in the field using Drierite (W. A. Hammond Drierite Co. Ltd., Xenia, Ohio, USA), subsequently this material was used for DNA isolations using the DNeasy Mini Plant kit (QIAGEN, Venlo Limburg, The Netherlands).
For the first part of their experiment, the authors gathered samples of 18-30 plants from two known populations of C. jimenezii. They then dried the leaf material of the Dominican Republic sample, using Drierite (an all-purpose drying agent most commonly used in storage spaces as it dries the air in the atmosphere). The DNA from these populations was isolated from the dried material using the DNeasy Mini Plant kit; the procedure was similar to the one described in the following video https://www.youtube.com/watch?v=rY-Qbrw9KMc
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Linkage disequilibrium values were of 20% for the population from Haiti and 6% for that from the Dominican Republic. The Gonaïves locality showed clear evidence of inbreeding with a large Fis positive value of 0.232 (Table 2).
The values of the Haitian population of palms were higher which means that there were more alleles that were associated non-randomly.
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Micosatellite SSR data have proven useful to reveal patterns
Microsatellites, have been used by geneticists on plants in order to identify gene loci and how they can affect a certain trait or disease.
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however, it appears that they are related to unusual rain fluctuations (Romero Luna, 2011). Because the Dominican Republic population of C. jimenezii is located near the shoreline of this lake, there is concern that the soils where the species occur can be negatively affected by saline intrusion.
The research here describes the changes in genetics that have been triggered by environmental factors so that the palms can deal with salt and increased water amounts.
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azareno and Dos Reis, 2014 A.G. Nazareno, M.S. Dos ReisAt risk of population decline? an ecological and genetic approach to the threatened palm species Butia eriospatha (Arecaceae) of Southern Brazil J. Hered., 105 (2014), pp. 120-129
Nazareno and Dos Reis review the ecological and genetics basis of the conservation of a threatened population.
Although population ecology parameters as well as genetic data are very important in the analysis of a population threatened with extinction, there are other factors such as policy actions and reinforcement that also play a role in this loss of biodiversity and should also be analyzed.
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Maunder et al., 2008 M. Maunder, A. Leiva, E. Santiago-Valentín, D.W. Stevenson, P. Acevedo-Rodríguez, A.W.Meerow, M. Mejía, C. Clubbe, J. Francisco-OrtegaPlant conservation in the Caribbean Island biodiversity hotspot Bot. Rev., 74 (2008), pp. 197-207
Authors review how human efforts made towards plant conservation can have an effect on the biodiversity of an area.
Although both environmental and genetic factors are needed for the survival of a species, the authors note other factors such as understanding the taxonomy, systematics and ecology of the flora, can be just as important in the survival of plant species.
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Höglund, 2009 J. HöglundEvolutionary Conservation Genetics Oxford University Press, Oxford (2009)
The authors review the role of inheritance in the survival of a population.
Although gene variability is important in a population, the authors note that the inheritance of the genes responsible for this variability may also play a major role in ensuring either extinction or survival of a population.
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Giovino et al., 2014 A. Giovino, S. Scibetta, S. Saia, C. GuarinoGenetic and morphologic diversity of European fan palm (Chamaerops humilis L.) populations from different environments from Sicily Bot. J. Linn. Soc., 176 (2014), pp. 66-81
The authors review the contribution of genetic diversity in the survival of species of palms.
The authors note that there is a clear relationship between genetic variability in a population and its chances of survival in degrading or changing environments.
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Foxx, 2012 R.M. FoxxTe Terre a fatige ‘the Earth is tired’: reversing deforestation in Haiti Behavio. Interv., 27 (2012), pp. 105-108
Foxx addresses the prevalent issue in Haiti regarding a major lack of plant biodiversity due to both human and natural forces.
Although very little can be done to combat natural disasters responsible for the decline in biodiversity in Haiti, the author notes that reforestation can at the very least lessen the effects that the aforementioned has on both the country and the planet.
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Duminil et al., 2009 J. Duminil, O.J. Hardy, R.J. PetitPlant traits correlated with generation time directly affect inbreeding depression and mating system and indirectly genetic structure BMC Evol. Biol., 9 (2009), p. 177
Duminil and his team, reviewed how a plant’s generation time can affect their genetic structure.
The authors note that the mating system of plants has a great influence in genetic differentiation between different species and that generation time can affect this mating system in some species, therefore, modifying genetic drift and flow in a population.
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erazaín Iturralde et al., 2005 R. Berazaín Iturralde, F. Areces Berazaín, J.C. Lazcano Lara, L.R. González TorresLista roja de la flora vascular cubana Doc. Jard. Bot. Atlántico, 4 (2005), pp. 1-86
The authors review the implications leading to and from red-listing flora in Cuba.
The focus surrounds the reinforcement of conservation of species that were part of the red-list, this paper notes that the global loss of biodiversity is a current issue which can affect areas like Cuba where environmentally there is potential for greater biodiversity.
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Alscher, 2011 S. AlscherEnvironmental degradation and migration on Hispaniola island Int. Migr., 49 (s1) (2011), pp. e164-e188
The authors explore the the concept of environmental degradation as an incentive leading to migration as a survival strategy of C. jimenezii.
Given the observed endangerment of C. jimenezii, the authors sought out answers outside of the C. jimenezii genetic makeup which could have led to the migration of the plants and how this affected their survival.
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llendorf and Luikart, 2007 F.W. Allendorf, G. LuikartConservation and the Genetics of Populations Blackwell, Malden (2007)
Allendorf and Luikart review the genetic challenges responsible for the conservation of a population threatened with extinction.
Although the authors concentrate on the genetic factors concerning plant conservation, they note that a true understanding of both plant and animal genetics is necessary to gather the tools needed to preserve a given species.
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Abbott et al., 1985 L.A. Abbott, F.A. Bisby, D.J. RogersTaxonomic Analysis in Biology Columbia University Press, New York (1985)
Abbott along his team of researchers, reviews the role taxonomy plays in understanding the origin of the species and such species’ proper conservation.
The authors recognize that differences in taxa, due to genetic variability, may affect the species’ overall survival and ultimate conservation methods which may currently be contributing to their endangerment.
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Therefore we recommend not translocating material between these two populations for genetic conservation or ecological restoration programs until the taxonomy of this species within Coccothrinax is further studied.
Genetic conservation of this population is important due to the few individuals left in Haiti and the Dominican Republic.
Upon meeting with the author, the difficulty of finding the purebred species was discussed as were the methods.
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The taxonomic uncertainties between the two populations of C. jimenezii have important implications for reintroduction programs. These two sites of C. jimenezii represent two clear management units for conservation, and the population genetic data suggest that we cannot rule out that they are two distinct taxa.
The authors concluded based off of the molecular data, that the two species of C. jimenezii could not be identified as two different taxa.
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hastula
The junction between the leaf and the stem blade.
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taxon
Unit of biological classifications of an organism. This can be a group of rank such as, species, family or class.
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The high levels of genetic differentiation detected within C. jimenezii raise questions whether these two populations can be treated as different varieties/subspecies
In this study, the researchers found some questions as to whether the two species of C. jimenezii could be grouped with the same taxa.
The authors used molecular tools which have found a large amount of differentiation. This was not what the authors hoped and in turn it was concluded that they were to remain in separate taxa.
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herbarium specimens
A collection of preserved plant specimen used for specific scientific study.
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homoplasy
A characteristic that is shared within species but not present within their ancestors.
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Nauman and Sanders (1991a) who suggested that it is composed of three major groups: the argentata group (with ten species, including the Critically Endangered C. crinita, C. cupularis, C. leonis, C. montana, C. victorinii, C. borhidiana), the argentea group (with six species, including the Critically Endangered C. spissa), and the pauciramosa group (with 31 species, including the Critically Endangered C. nipensis, C. pauciramosa and C. yuraguana). Nauman and Sander's (1991a) phylogenetic research was based on morphological traits.
This taxonomic research was done in 1991 by Nauman and Sanders. Essentially it explained why there is genetic diversity amongst the Coccothrinax populations, and it is essentially because they come from three main groups each comprised of different traits.
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biodiversity crisis
Biodiversity entails all form of life and ecosystems in the planet. The planet needs this biodiversity to support the existence of all life on earth. However, over the last couple of years humans have greatly reduced the Earth’s biodiversity leading to the extinction of whole species and the endangerment of others. If we want to continue existing on this planet is important to work towards protecting biodiversity on our planet.
Read more about it: https://www.bgci.org/plant-conservation/why_conserve/
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In an unpublished study focusing on the genetic structure of con-specific populations of Coccothrinax argentata from the Lower Florida Keys and the Florida mainland, Zona et al. (in preparation) found a much lower Fst value of 0.24.
This study yielded a Fst value, which essentially describes the degree to which a population interbreeds and how freely they do so. The current Fst value are very low compared to what was found in the experiment done in this paper. This is cause for further testing.
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We have not been able to find data regarding the environmental history in these two populations since the 15th century. However, there is agreement among conservation biologists that since the arrival of the Europeans to this island there has been habitat fragmentation and deforestation linked to rapid expansion of urban and rural activities (Sambrook et al., 1999; Alscher, 2011; Foxx, 2012). Palms have long-life cycles; therefore, the detrimental consequences of genetic drift on genetic diversity can take a long period of time to manifest because of their long generation time and the presence of overlapping cohorts (Duminil et al., 2009).
Since the extinction of C. jimenezii is of primary concern, the authors use resources from other works to help solidify this concept. It is clear that the conservation of this species is vital to this study.
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