In general, when the mammalian body encounters a foreign object, be it a pathogen causing disease or an allergic nonpathogenic molecule, the immune cells in the system are triggered and begin a cascade of reactions in an attempt to contain and eventually eliminate the foreign entity.

White blood cells

Somatic refers to all the cells of the body that are not germline cells (eggs or sperm).

Germline cells are the sex cells in the body (sperm in males and eggs in females).

A genus of flies that are often used as model organisms in research. They are commonly called "fruit flies."

A chimeric fly has two distinct cell populations. In this case, a mutagenic event occurred early in the development of the female chimera, causing it to have one genotype on one half of its body, and a different genotype on the other half.

Refers to the phenotype of an organism as it was found in nature. In contrast to a mutant allele, the wildtype phenotype is the product of the "normal" allele for a particular gene.

A genetic element is autocatalytic if it converts the companion chromosome to its own state.

Homology arms are DNA sequences in a plasmid that are identical to a specific genomic DNA sequence. The homology arms are used to direct homologous recombination of a plasmid into the genome.

Mosaic organisms have multiple cells populations with different genotypes. In this case, the mosaic flies had small patches of brown color but were mostly yellow.

Lakes, rivers, streams, etc. (NOT the ocean)

Lakes, rivers, streams

susceptible

Amount of time a molecule exists before it is broken down

Light travels from place to place in the form of a wave. All types of light have a characteristic wavelength. In the visible spectrum, red light has the longest wavelengths and purple has the shortest. UV light has shorter wavelengths than visible light.

Headwater streams are small, shallow streams that carry water from the surrounding land area into a main river.

Indicates that the water in this river came from melting glaciers

The amount of time that water stays in a lake before evaporating or flowing into another body of water.

Benthic is a word used to describe things that take place in the sediments at the bottom of a body of water.

Bacterial respiration is when microbes “eat” organic carbon, causing it to break down into smaller molecules. In most cases, bacteria require oxygen to break down organic carbon.

Photochemical oxidation is when sunlight and oxygen react with organic carbon, causing it to break down into smaller molecules

The invisible component for sunlight that is responsible for sunburn and breaks down organic compounds. UV light has a shorter wavelength than visible light. See this link for more information.

This video, made by people who work with primary author Rose Cory, explains what photodegradation is.

In other words, over the area where rain water flows into the river and lake system we studied.

Mineralization refers to the break down of organic molecules to inorganic molecules. For the purposes of this paper, it means conversion of organic carbon to carbon dioxide.

N represents the number of samples tested.

Quantum yield is a measurement of how much of a chemical reacts when exposed to light. For example, in this study it would be the amount of carbon dioxide produced divided by the amount of UV sunlight absorbed by dissolved organic carbon.

The day in the spring when all of the ice in a lake has melted.

Areal rate refers to the amount of something that happens over an amount of surface area. For example the rate of bacterial respiration is measured as the amount of oxygen released per day, but the areal rate would be measured as the amount of oxygen released per square meter per day.

This refers to how we interpret our own behavior as well as the behaviors of the people we interact with.

Remediation means trying to resolve a problem once it has already occurred. In this case, the author is referring to remediating violence.

Baseline measurements are measurements that report on the sample population prior to the experiment. In this case, prior to the start of the jobs summer jobs program, 20% of the youth in the study had been arrested and 20% had been victims of violent activity.

By operative mechanism, the author is referring to the thing or factor that helps us understand why this summer jobs program helps reduce violent crime.

Empirical literature refers to articles that are based on data that has been collected in a field (real-world) or laboratory setting. Because science is a process that builds upon itself, scientists are always looking to see what the existing empirical literature establishes so that a study that presents something new can be designed.

In this experimental study, outcome measures refer to violent activity as well as other types of crime and schooling outcomes. This paper reports specifically on whether summer jobs have any affect on violent activity.

What is a disturbance, in this context? In ecology, a disturbance is anything that changes the ecosystem. For example, a forest fire, tornado, human activity (building more houses in an area that used to be a grassland), etc.

Not being allowed to do a particular activity (in this case, cut down forests) for a set amount of time

Aggregate dynamic refers to the combination of forest loss and gain.

Why do boreal forests grow slower than other forest types? For starters, boreal forests have shorter growing seasons. Also, boreal forests have only conifer tree species that do not grow as quickly as deciduous trees.

Why is carbon storage important? Find out by following this link to explore carbon "sequestration" (just a fancy term for "storage") and how this process can help curb global warming.

What are important ecosystem services that forests provide?

First, let's break this down into what an ecosystem service is. These services include any benefit that an ecosystem can provide to people.

So, what can forests provide that benefit people? Here are some examples: Forests provide timber, store carbon, purify air and water, and provide space for recreation (e.g., hiking in the woods!).

Richness is simply the number of different species.

Biodiversity refers to the diversity of biology (a.k.a. the number of different species).

Putting this all together, we can determine that forests, compared with other types of ecosystems (e.g., deserts), have a lot of different species of plants, animals, bacteria, etc. (this is especially the case in tropical forests).

Describes where things are in relation to each other. In this case, the satellite images of Earth provide a clear picture of where forests are located and distributed.

Imagine having spatially explicit data of Earth's surface, all collected at the same time. This is what satellite-based imaging systems do. By examining these pictures over time, we are able to map forest loss and gain. Imagine trying to do this task from the ground. It would be very hard indeed.

Tropical: Areas near Earth's equator that are warm/hot year-round with consistent or seasonal rainfall.

Subtropical: Areas with hot and humid summers and mild winters.

Temperate: Areas with four seasons (summer, fall/autumn, winter, and spring) divided mainly by differences in temperature.

Boreal: Subarctic areas with long, cold winters and short, cool summers.

Check out where these climate domains/zones are around the world on this map.

"Deforestation dynamics" refers to changes (i.e., dynamics) in forests due to cutting down trees and replacing them with nonforest land uses, such as agriculture or development (houses, buildings, etc.).

This wording implies that Hansen and colleagues ran a statistical model to determine whether the loss or gain in forest cover over time was more or less than what you would expect if forest cover did not change.

The tropics experienced a clear increasing rate of forest loss, expressed in units of forest area loss per year, whereas other climate domains (e.g., temperate, boreal, subtropical) all lost and gained forest cover

However, when you add all of the subtropical regions of Earth together, for instance, there isn't a clear net loss or gain in forest cover. This is because of the fact that most forest change in the subtropics is due to forestry land uses where trees are grown as a crop. In forestry land uses, trees are continuously grown and cut down to make products such as lumber and paper.

This statement refers to "short rotation forestry," which is a type of forestry that densely plants fast-growing tree species (e.g., poplar trees).

Once these trees reach a certain size (e.g., stems that are 10–20 cm in diameter at breast height), they are then cut down and harvested for lumber, pulp, and paper products, or energy.

The trees then regrow from the stumps, sending up new trunks. This process of cutting down a tree to stimulate regrowth is called "coppice."

In this context, the authors are describing the satellite images—these images are widespread (e.g., systemic) in that they photograph the entire surface of Earth.

The authors used Google Earth Engine to process the Landsat images.

The Google Earth Engine is a cloud platform, meaning that a network of thousands of computers works together to perform a task that a single computer would take years to do.

Similarly, Google Cloud provides the same features. Google Cloud allows you to store, manage, and process information on computer servers that are accessed through the Google Cloud website.

Cloud computing is especially helpful for processing large amounts of data/information.

Hansen and colleagues processed 700,000 images of Earth. Processing this information through the Google Earth Engine with 10,000 computers took approximately 15 days. If the authors only had one computer to work with, these calculations would have taken a few years!

a small object often used as part of a piece of jewelry. This could for instance be a string of perles.

a place where two or more roads or railway lines meet

annotating the word plant.

Connections in the brain between brain cells (neurons) in the cortex (the surface level, grey-matter of the brain).

Click here to see a picture of the cerebral cortex

The belief that something is much worse than it actually is.

interactions between people, for example when you have a conversation with someone or work with other people to solve a problem.

Smells

Sounds

A measure that reflects the amount of time participants spent in slow-wave sleep and rapid-eye-movement sleep.

It is calculated by multiplying the number of minutes of SWS by the number of minutes of REM sleep.

Declarative memories are memories of facts (e.g. the U.S. Declaration of Independence was signed in 1776) and personal life events (e.g. your 10th birthday).

Declarative memories are generally able to be consciously recalled.

Click here for more information

DNA binding proteins recognize and bind with specific DNA sequences. They are useful not only in genomic editing but also in regulation. http://www.wiley.com/college/pratt/0471393878/student/structure/dna_binding_proteins/index.html

Other genes derived from a common ancestor

These are the two existing commonly used genetic editing strategies.

Sanger sequencing is a method of reading DNA codes which relies on normal and modified deoxynucleosidetriphosphates (dNTPs). The modified dNTPs terminate the sequence prematurely, and the sequence is then assayed https://www.thermofisher.com/us/en/home/life-science/sequencing/sanger-sequencing/sanger_sequencing_method.html

This is a method for rapidly increasing the amount of a sample of DNA by artificially replicating the DNA using a polymerase.

A DNA sequence derived from self.

Editing using more than one targeting strategy.

In non-homologous end joining splices in DNA are repaired by splicing rather than by referring to an intact complementary strand of DNA. This method of repair is less accurate than homologous recombination.

This is the integrated reporter mentioned earlier in the paragraph.

Induced pluripotent stem cells come from adult cells which have been artificially changed to exhibit stem cell properties. These properties are immortality and the ability to develop into various different cell types. These cells are thus unspecialized. https://www.thermofisher.com/us/en/home/references/protocols/cell-culture/stem-cell-protocols/ipsc-protocols/generation-human-induced-pluripotent-stem-cells-fibroblasts.html

This cell line is derived from myelogenous leukemia cells and is considered an excellent target to test the function of natural killer cells. http://www.atcc.org/products/all/CCL-243.aspx

These cells are the human embryonic kidney cells mentioned above.

These are genes which are expressed in almost all the cells or an organism.

Chromosome 19 includes about 1500 genes and 59 million base pairs. For a brief summary of chromosome 19 see http://ghr.nlm.nih.gov/chromosome/19

This is a gene concerned with protein phosphatase regulation http://www.genecards.org/cgi-bin/carddisp.pl?gene=PPP1R12C

This is a site on human chromosome 19 which the adeno associated virus type 1 targets.

The researchers now turned to modifying a natural DNA sequence.

The integrated reporter was the green fluorescent DNA sequence which was integrated into the target DNA. The green fluorescent sequence could then be manipulated, and the results could be measured.

http://www.genecards.org/cgi-bin/carddisp.pl?gene=DNMT3A

DNA strands have 2 ends, a 3' end and a 5' end. The 3' end is joined to the 5' end of the complementary strand.

This is an enzyme which nicks specific sites in the genome without damaging unintended sites.

Heterodimers are molecules composed of two different macromolecular chains.

A transcription activator-like effector nuclease is an artificial restriction enzyme (enzyme that cuts DNA at a specific spot). Talens are created by fusing DNA binders to DNA cleavers. They are modeled from proteins secreted by Xanthomonas bacteria. http://bfg.oxfordjournals.org/content/early/2014/06/06/bfgp.elu013.full

Multiplex editing aims either to make several different changes at once or changes in several different locations of the genome at once.

Exons are parts of genes that code for proteins.

Homologous recombination is a naturally occurring method of repairing breaks to DNA. This method relies on the unbroken strand of DNA to correct errors on the broken strand. https://www.qiagen.com/us/shop/genes-and-pathways/pathway-details/?pwid=143

This is a site on human chromosome 19 which the adeno associated virus type 1 targets.

Since DNA consists of a double strand, the bases form into pairs such that cytosine always pairs with guanine and adenine always pairs with thymine. A 68 bp sequence would contain 68 of these pairs.

This means that the green fluorescent protein is integrated into the host's DNA

A stable cell line is one in which there is little variation from one cell to another. Another desirable characteristic of stable cell lines is that most of the cells are not actively dividing unless they are stimulated to do so by the researcher. https://www.mirusbio.com/tech-resources/tips/generate-stable-cell-lines

These cells were developed from the kidney of a human embryo. They are easy to grow, and it is easy to introduce foreign nucleic acids (RNA and DNA fragments) into them. http://www.atcc.org/products/all/CRL-3216.aspx#documentation

The system can target sequences between one guanine (G) followed by 20 nucleotides (pairs of amino acides) and ending with two guanines in a row (GG).

The U6 gene is commonly found throughout the human genome. It is also a well studied gene

The PAM is a short DNA sequence close to the targeted DNA sequence of the invading organism. The PAM is crucial for the system to recognize whether or not the DNA sequence is self or not self. If the PAM is missing the system will not be activated

An enzyme important in the production of short RNA

The Cas9 protein is the hallmark protein of type II CRISPR systems

Genome engineering is targeted change in the DNA sequence.

In contrast to DNA, which is a double strand of linked amino acids, RNA is a single strand. The four "letters" in the DNA alphabet are adenine, thymine, cytosine, and guanine. RNA is made up of adenine, thymine, and cytosine, but in place of guanine it has uracil.

Breaking

Eukaryotic cells have a membrane around their nucleus, in contrast to prokaryotic cells such as bacteria or archaea.

Deoxyribonucleic acid (DNA) is a double stranded helix (coiled in a spiral) of proteins which form a sort of "alphabet" to encode genetic information. The "letters" of this alphabet consist of adenine, thymine, cytosine, and guanine.

Adenine always pairs with thymine, and cytosine always pairs with guanine, thus, when the two strands are divided the complete DNA molecule can be exactly reproduced. http://ghr.nlm.nih.gov/handbook/basics/dna

Plasmids are circular double stranded DNA fragments which can insert themselves in a cell and thenceforth be reproduced in cell divisions even while staying apart from the cell's own DNA. Plasmids can spread resistance to antibiotics from one strain of bacteria to another. They are also important for genetic engineering because they can be used for targeted DNA changes. http://www.nature.com/scitable/definition/plasmid-plasmids-28

Viruses are submicroscopic parasites with a simple structure. Their main parts are a strand of nucleic acid (DNA or RNA) and an surrounding protein shell called a capsid. Some viruses also have an outer viral envelope surrounding their capsid. Viruses are not capable of reproducing on their own, but rather must invade a cell and commandeer that cell's resources to reproduce themselves http://www.ncbi.nlm.nih.gov/books/NBK21523/

CRISPR associated proteins are proteins which act in concert with the rest of the CRISPR system to mediate its activities. These proteins are grouped in families. The types of proteins present characterize the distinction between type I, type II, and type III CRISPR systems http://www.biologydirect.com/content/6/1/38

CRISPR RNAs are short strands of RNA transcribed from the CRISPR loci which play an important role in targeting foreign DNA https://www.neb.com/tools-and-resources/feature-articles/crispr-cas9-and-targeted-genome-editing-a-new-era-in-molecular-biology

Induced pluripotent stem cells are cells derived from adult tissue which have been artificially made to act like stem cells. In other words, they have been forced to be capable expressing the full range of their gene capacities instead of specializing as adult cells normally do http://stemcells.nih.gov/info/basics/pages/basics10.aspx

293T cells were originally derived from the kidney tissue of a human embryo. They have been modified to contain the SV40 T antigen, thus giving this cell line advantages for work with retroviruses. http://www.atcc.org/products/all/CRL-3216.aspx#characteristics

SV40 T antigen is associated with Simian Virus 40, a tumor producing virus which is in the Polyomavridae family http://www.nature.com/onc/journal/v24/n52/full/1209046a.html

Guide RNA is a genetically engineered fusion of crRNA and tracrRNA. It targets the RNA sequence of interest and enables it to bind with the Cas9 nuclease https://www.addgene.org/CRISPR/guide/

There are three types of CRISPR systems: Type I, II, and III. Type II is the simplest type and is characterized by an operon (functional DNA unit) of only four genes: cas9, cas1, cas2, and either cas4 or csn2. https://dpb.carnegiescience.edu/sites/dpb.carnegiescience.edu/files/Bhaya_ARG.pdf

Clustered regularly interspaced short palindromic repeats (CRISPRs) are strands of DNA with repeating sequences (repeats) interspersed with other sequences which don't repeat (spacers).

Like bacteria, archaea are also prokaryotes. Archaea have similar appearance and behavior to bacteria but differ greatly from bacteria in their genetic structure. Many archaea live in extreme environments such as extremely hot or cold areas or areas with high salt concentrations http://www.microbeworld.org/types-of-microbes/archaea/42-what-is-a-microbe-sp-828/types-of-microbes/149-archaea

Bacteria are prokaryotes. This means that they don't have a nucleus to contain their DNA. In contrast, eukaryotes have a nucleus which contains their DNA. http://www.microbeworld.org/types-of-microbes/bacteria

Fully defined systems are standardized. Individual variations are minimized, thus enabling to system to yield predictable results.

In vitro means "in glass". This is used to refer to an experiment conducted in laboratory containers rather than in a natural environment

Having to do with mental processes for example memory, language, problem solving, and creativity.

Having to do with emotions

The process by which memories become more stable (less likely to be forgotten). The authors' work is based on previous findings that sleep is particularly important for memory consolidation.

The use of race, ethnicity, religion, or national origin to determine on which people law enforcement agencies conduct stops, searches, and other investigative procedures. Racial profiling is based on the false assumption that one race is more likely to commit crimes than another.

Click here for more information on racial profiling

Also known as REM. This period of sleep is when most dreams are thought to occur.

Also known as 'deep sleep.'

Unconscious, outside of awareness and control

The idea that all people are equal and deserve equal treatment

Glossary test

Yar yar

Foo bar

hello!

test test test

winter is here

A region

Big term

Heavy!

Near the threshold for fault slip and earthquakes

The outside of a micelle.

The center of a micelle.

This term is used to describe solutions that have limited to no transparency; cloudy, opaque.

The growth of one crystalline material on the surface of another crystalline.

In this case, the crystalline surface upon which epitaxial growth occurs is the exposed crystalline core of the cylindrical micelle. The exposed core can continue to elongate as more block copolymers are added to the solution.

A solution that has evenly dispersed particles that are 1 nm to 1000 nm. The particles are in solution and do not settle out. An example of a colloidal dispersion is milk.

Maximum end-to-end distance of a linear polymer chain.

In a block copolymer, a block which lacks crystallinity and has great freedom of rotation due to its flexible nature.

A type of polymerization mechanism that uses strained cyclic olefins (alkene) as the monomer source to produce polymer chains.

A chemical compound that has a hydrophilic (water-loving) component and lipophilic (fat-loving) component.

A cross-link bonds together different polymer chains together at a specific site (i.e., double bonds, sulfur atoms) to form a larger polymer network.

Glossary: Molecules have different degrees of molecular symmetry. A molecule that is noncentrosymmetric will not contain an inversion center or a center of symmetry. An example of a molecule that is centrosymmetric is a benzene ring (C6H6) where the inversion center is the center of the ring.

Anisotropy is defined as having a directional dependence. In the case of shape, anisotropy it is referring to an object that is not spherical.

Particles of any shape that have at least one dimension less than 100 nm or less in size.

The formation of complex structures from a bottom-up approach.

From one direction or side.

A micelle is an aggregate comprised of amphiphilic molecules. A micelle will have a core (inside-lipophilic) and a corona (outside-hydrophilic).

The individual components that make up this aggregate are referred to as unimers.

Although most micelles are have hydrophobic cores and hydrophilic corona, these micelles don't fit this classification. The corona is PI (hydrophobic) and the core is PFS (also hydrophobic). Self-assembly is induced because hexane/decane are poor solvents for PFS but good for PI .

Molecular self-assembly is the process in which a disordered group of molecules occupy some organized arrangement without direction from an outside source.

A block copolymer is a polymer chain comprised of homopolymer subunits linked by a covalent bond.

For example:

Homopolymer (where A is the monomer unit) : A-A-A-A-A-A-A-A

Block copolymer (where A and B are monomer units): A-A-A-A-B-B-B-B

As the field of nanotechnology continues to grow, the ability to carefully control nanoparticle size, shape, and composition still remains a challenge. Most nanoparticles exhibit a great deal of symmetry. The authors of this paper focused on developing a method to create block copolymer micelles that had very little symmetry (i.e., noncentrosymmetric). They were able to achieve their goal through unidirectional micelle growth. The authors later used this same strategy to synthesize a "supermicelle."

Cytoskeleton is a network of fibers composed of proteins (microfilaments made of actin and microtubules made of tubulin) contained within a cell's cytoplasm.

Coimmunoprecipitation (Co-IP) is the immunoprecipitation of intact protein complexes. Co-IP works by selecting an antibody that targets a known protein that is believed to be a member of a larger complex of proteins. By targeting this known member with an antibody it may become possible to pull the entire protein complex out of solution and thereby identify unknown members of the complex.

Immunoprecipitation (IP) is the technique of precipitating a protein antigen out of solution using an antibody that specifically binds to that particular protein. This process can be used to isolate and concentrate a particular protein from a sample containing many thousands of different proteins.

Western blot is an analytical technique used to detect specific proteins in a sample of tissue homogenate or extract.

The pull-down assay is an in vitro method used to determine a physical interaction between two or more proteins.

Triton X-100 is a detergent widely used to lyse cells to extract protein or organelles, or to permeabilize the membranes of living cells.

Point mutation is a technique in which a single base nucleotide is replaced with another nucleotide. As a result, the mutant protein has a different primary sequence with respect to the wild-type protein.

Zinc finger is any small, functional, independently folded protein domain that requires coordination of one or more zinc ions to stabilize its structure and is essential for DNA- or RNA-binding protein-protein interactions and membrane association. http://www.ncbi.nlm.nih.gov/pubmed/11179890

Viral titer is a way to express concentration. It refers to the concentration of viruses in a sample.

IAV was introduced into the trachea of mice.

RNAi is a biological process in which RNA molecules inhibit gene expression, typically by causing the destruction of specific mRNA molecules. The final result is the depletion of specific target proteins.

Aggresomes are dynamic structures, formed of improperly folded proteins.

Ubiquitin is a small regulatory protein that has been found in almost all eukaryotic cells. Ubiquitin binds to proteins and labels them for destruction.

Tubulin is the protein that polymerizes into long chains or filaments that form microtubules, hollow fibers which serve as a skeletal system for living cells.

Hemagglutinin is a glycoprotein found on the surface of the influenza viruses. It is responsible for binding the virus to cells.

A conformational change is a change in the shape of a macromolecule, often induced by environmental factors.

Endosomes are membrane-bound vesicles, formed via a complex family of processes collectively known as endocytosis, and found in the cytoplasm of virtually every animal cell.

A host cell is a living cell invaded by or capable of being invaded by an infectious agent (as a bacterium or a virus).

The genome of influenza A viruses consists of eight segments of single-stranded, negative-sense RNA that are encapsidated as individual rod-shaped ribonucleoprotein complexes (RNPs). Each RNP contains a viral RNA, a viral polymerase and multiple copies of the viral nucleoprotein (NP).

A supramolecular complex is a well-defined assembly of molecules held together by noncovalent bonds. While a supramolecular assembly can be simply composed of two molecules (e.g., a DNA double helix), it is more often used to denote larger complexes of molecules that form sphere-, rod-, or sheetlike species.

A capsid is the protein shell of a virus. The capsid encloses the genetic material of the virus.

Viral RNA with a base sequence complementary to that of mRNA; during replication it serves as a template for the transcription of viral complementary RNA. Negative-sense (3' to 5') viral RNA cannot be translated into protein directly. Instead, it must first be transcribed into a positive-sense RNA (5' to 3') which acts as an mRNA. Some viruses (influenza, for example) have negative-sense genomes and so must carry an RNA polymerase inside the virion.

Coalescence is a merging of two units. For example, here the authors consider that Middle East or China are unlikely centers of dog origin because such a scenario would require that ancient wolves and dogs from these areas are united by a common ancestor.

A population bottleneck is the reduction of the population size, followed by an expansion, e.g. a small group leaves the first population and immigrates elsewhere.

This reduction often leads to the loss of genetic diversity in the population; it is called the founder effect.

Stochasticity is randomness; in this context, the fact that several lineages mixed resulted in different offspring but each did not recapitulate all the characteristics of its ancestors.

A phylogeny is the method to resolve the evolutionary history of a group of species. The relationship between these species can be inferred from various statistical analyses that estimate the genetic relatedness of each species to one another, depending on their differences either in DNA or protein material.

DNA located in the mitochondria. All animal mitochondrial genomes, with a few exceptions, contain the same 37 genes, making them useful as a model for genome evolution.

Specifically, the comparison of mitochondrial gene arrangements in animals has been critical to inferring ancient evolutionary relationships.

Phenotypic variation is the variability of all observable or measurable characteristics of the individual animals.

Phenotypic variation is the variability of all observable or measurable characteristics of the individual animals.

Commonly accepted.

Stochasticity is randomness; in this context, the fact that several lineages mixed resulted in different offspring but each did not recapitulate all the characteristics of its ancestors.

Phenotypic variation is the variability of all observable or measurable characteristics of the individual animals.

Molecular dating is a technique that allows biologists to determine the divergence time for two genes or for two species. It is based on the theory of the molecular clock stating that mutations accumulate in organisms at a stable speed.

Thus, if you compare genes or protein sequences in different species, you can, assuming you know the speed of variation for these sequences, estimate the age of the last common ancestor.

A phylogeny is the method to resolve the evolutionary history of a group of species. The relationship between these species can be inferred from various statistical analyses that estimate the genetic relatedness of each species to one another, depending on their differences either in DNA or protein material.

DNA located in the mitochondria. All animal mitochondrial genomes, with a few exceptions, contain the same 37 genes, making them useful as a model for genome evolution.

Specifically, the comparison of mitochondrial gene arrangements in animals has been critical to inferring ancient evolutionary relationships.

Definition of citators.