- Oct 2019
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If costs of plasticity are significant,selection should drive the loss of sporulation ability; alternatively,sporulation ability could be lost via mutational degradation. Maselet al.(2007) showed that, in general, mutational degradation is a moreimportant limit for rarely used plasticity whenever the functionalmutation rate is greater than the selective coefficient
I think that this is a very interesting point. I don't think that I had ever thought that the costs of plasticity would ever be so significant that they would be lost through selection. This is an important point to show the limit for rarely used plasticity. This makes me want to understand more about how/why these types of species were originally plastic at all.
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Consider the facultative production of a head spine inDaphniain response to chemicals emitted by predators (kairomones).Suppose theDaphniapopulation consists of three genotypes: genotype1 constitutively produces short spines (G1fixed 200μm spines legendFigure 1), genotype 2 constitutively produces long spines (G2fixed800μm spines legend Figure 1) and genotype 3 produces a short spine(200μm spines) in the absence of predator cues, but a long spine(800μm spines) in their presence (thus, G3 has plastic spine lengthchanging from 200 to 800μm between environments, legendFigure 1). In an environment with no predators, genotype 1 hashigherfitness than genotype 2; genotype 2 has incurred aphenotypecost(Figure 1), a situation reversed if predators were present. Thus,phenotype costs are genotype specific and environment dependent,that is, they are local costs. In each environment, we can evaluate thecosts andfitness benefits of a particular phenotype in comparison tothose of alternative phenotypes. Aplasticity costensues in this examplewhen two genotypes produce the same phenotype (for example, longspines 800μm; Figure 1), but the more plastic genotype 3 has reducedfitness compared with the non-plastic long-spined genotype 2
This is an excellent example that really helped me understand the difference between a "cost of plasticity" vs a "cost of phenotype". When looking into this it explains that the least beneficial phenotype (short spines in high pred. environment) clearly has the greater cost of phenotype. What helped me understand "cost of plasticity" explained that G2 (long spines) was more beneficial to the plastic genotype (G3 long spines w pred. short with abs of pred.) This would therefore mean that G3 had a cost of phenotype when in an environment with pred. present. I thought that this was a key idea in understanding the limits of plasticity.
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Babies could have their predisease micro-biota restored, and adults too, particularly women, who play a particularly important role in transmitting the human microbiota to the next generation.
This is an interesting thought. I would like to know more about how this process would work. Would this actually be beneficial? Would reintroducing the microbiota actually work to be a "self-transplant". I understand the concerns with the regulations among the FDA, but I would like to know if tests have been conducted and more information has been recorded on this idea.
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Bacteria acquired during labour include lactic acid bacteria that digest lactose, and others that use substrates that are indigestible for the babies (indi-gestible milk glycans knownashumanmilkoligosaccharides, or HMOs),38 39with polymorphisms, such as in fucose trans-ferase gene FUT2, associated with selective effects of HMOs on the infant microbiota composition,40 which in turn can affect the susceptibility to immune diseases later in life
In this excerpt where it says “bacteria acquired during labor...” I assume this refers to vaginal births. With that assumption made this makes sense to a connection I can make in my own life. I was born via C section and when I was a baby I could not drink milk of any kind and was placed on a soy formula. If this passage is referring to the idea that bacteria required to digest lactose, etc. are acquired through vaginal birth that makes sense as to why as a baby my body could not! Interesting connection!
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Whether the primordial inoculum contains most microbes that will be nurtured by the child, and which maternal strains colonise which parts of the baby’s body and their func-tions, the paternal and sibling contribution along with the infant’s microbial diversity33 and the extent to which modern practices reduce intergenerational transmission, are still not completely understood. C-section as intrapartum antibiotics during vaginal delivery alter bacterial colonisation in the neonates
This is an interesting point explaining that there is still much that is unknown about the topic. This excerpt goes on to explain that we understand that maternal strains colonize with different parts of the infants body yet we are still unsure of all of their functions as well as if there is more that contributes to what it may be. It is also and interesting point to mention that there may be a difference in outcomes when comparing a vaginal birth to a C section birth due to the fact that with a C section birth they would not have that exposure to the microbes in the vagina. I would be very interested in seeing what the differences in these two are.
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Weconcludethatanepigenetic conservationperspectivewillprovideenvironmen-talmanagersthepossibilitytorefineESUs,tosetconservationplanstakingintoaccountthecapacityoforganismstorapidlycopewithenvironmentalchanges,andhencetoimprovetheconservationofwildpopula
This is further explaining the goal of how an epigenetic conservation perspective can be beneficial (see box 1 for more) but this is a nice conclusion to have come to as well as an important goal to establish.
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heseepigeneticelementscanactinconjunctionwithgeneticinformationtomodulatepheno-typesduringdevelopment(Allis&Jenuwein,2016).Moreover,whilesomeepigeneticpatterns(i.e.epigeneticstatusatagivengenomiclocation)areundergeneticdeterminism(Box1),someothersaredirectlymodulatedbythesurroundingenvironmentalcondition
This is explaining how epigenetics can play a crucial role in development as well as be influenced by the environment.
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helastdecadeshaveflourishedwithbothempiricalstudiesandtheoreticalmodels,showingthatepimu-tations(i.e.changesinepigeneticstate)cangeneratephenotypicvariantsincludingkeymorphological,physiological,behaviouralandlife-historytraitsuponwhichbothnaturalselectionandsexualse-lectioncanact(Danchin,Pocheville,Rey,Pujol,&Blanchet,2018;Klironomos,Berg,&Collins,2013;Pál&Miklós,1999).
This right here explains a key reason why an epigenetics based perspective is useful in the field of conservation biology. It is understood that these "epimutations"play a role in determining phenotype (morphology, behavior, etc.) that can lead influence natural selection as well as sexual selection.
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- Sep 2019
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Thus, untangling the complicated relationship between epigenetic variation and changes in gene expression is a significant problem to overcome.
This is an excellent spot to discuss Q1 Why do we care as well as Q5 how this is relevant for both conservation bio as well as human health. The information learned in this article, leads me to believe that there is a lot that we do not currently understand about the concept of epigenetics. Gathering a better understanding of this would help conserv bio in ways that we have discussed in class as well as what the majority of the paper discusses. A better understanding of the world around us and how to enact the 5 main goals of conservation biology. This understanding would also help in the human health field by better aiding in understanding human genetics and how to care for those. Epigenetics can help us understand diseases for example cancer. Knowing what genes are "turned on" and "turned off" can help connect the missing points as to why are some people susceptible to things that others, especially in the same family, are not.
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The mustardArabidopsis thaliana provides a unique opportunity to demonstrate how inher-ited epigenetic polymorphisms contribute to complex phenotypes, and how they may under-lie the evolution of development in natural populations
This is an example where epigenetic modifications link to phenotype in A..thaliana, or what we know as a mustard plant. In short, it is depicting how the same species is altered in different locations throughout Europe. Data of methylation polymorphisms was also investigated along with their flowering times.
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