(Solved) Not sure how to understand this question

Mateyman

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3 years ago Edited: 3 years ago, Mateyman

Not sure how to understand this question

This is for a molecular evolution class. I alrdy reached out to instructor but this is due by Monday so I'm not sure I will get a reply, but I was hoping someone more learned tell me how they interpret the question?

Heres the question:

How do you define/describe evolutionary importance in regards to the 5 evolutionary forces given?

Is the evolutionary importance the list given such as gene conversion, generation time, or its telling me what kind of evolutionary importance is something like gene conversion is?

Would me defining what "biased gene conversion" is followed by an example from class be enough in your opinion?

Was hoping to see how you interpret this question and how would you answer it?

Or should I talk about how the term, say biased gene conversion is important because it showed us out gene conversion is behind things such as adaptive function of recombination and genetic disease of humans etc?

But then how would I define the evolutionary importance? Cos my answer above is just describing why its important but I'm not sure how to define why its important or is it kinda the same answer?

So quick summary haha:

- Do I define the evolutionary force + follow it up with an example from class

- Or I only talk about why the evolutionary force is important in evolution and then follow it with example from class, but then how would I define the evolutionary importance?

Thanks!!

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bio_man

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3 years ago

What your professor is asking is that you describe the evolution importance of "biased gene conversion" using an example from class. Start by defining what is it, and how it influences evolution. Not sure what examples were used in class. You have to do this for 3 others in the list, and it doesn't all have to relate from the same species.

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Mateyman Author

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3 years ago

Yeah that's kinda what I thought it meant as well. Define > explain how its important > relate to class

I can define and relate to class but kinda needs help on why its important.

For biased gene conversion after I defined it, I put its important cos it helped us understand adaptive function of meiotic recombination. Where, the ordinary segregation of 4 products of meiosis used to be 2A:2a, now due to gene conversion events we see alternative pathways like 3:1, 1:3 etc.

Would you say this suffices for why its important or you got other thoughts/

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bio_man

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3 years ago

Hi Mateyman

Read the abstract for this study: https://genomebiology.biomedcentral.com/articles/10.1186/s13059-018-1613-z

It explains how they use biased gene conversion to explain their findings. Maybe you could add that to your explanation of why it's important.

Let me know if you need further assistance.

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Mateyman Author

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3 years ago

Thank you mate, yeah I can see why biased gene conversion is important.

Any other recommendations/papers for the other terms?

Mainly homeologs, diploidzation, and selective sweep.

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bio_man

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3 years ago

Generation time hypothesis -- ncbi.nlm.nih.gov/pmc/articles/PMC2637270/

Differences in generation time could affect substitution rates, causing lineage effects on substitution rates if organisms with shorter generation times experience more mutations per unit of chronological time than organisms with longer generation times. This neutral explanation for rate heterogeneity among lineages is commonly called the generation time hypothesis. Under the generation time hypothesis, lineage-specific heterogeneity in rates of divergence can be explained by differences in the number of germ line cell divisions per unit time among lineages that otherwise share constant mutation rates. Therefore, under the generation time hypothesis substitution rates are expected to be negatively correlated with generation time [5,8,9]. Generation time effects on synonymous substitution rates have been widely observed at multiple loci for several mammalian species [2,3,9-15]. Generation-time-like effects have also been tested for in organism such as RNA viruses where faster substitution rates were correlated with higher frequencies of replication [16] and in spore-forming bacteria where rates of divergence were not related to spore dormancy [17].

In angiosperms, expected generation time impacts on rates of molecular evolution are not as clear as in animals since plants lack distinct germ and somatic cell lines. Plant cells are totipotent and the number of cell divisions between germination and gamete production can vary from individual to individual and even among parts of a single individual. The generation time hypothesis modified for plants assumes that variation in the frequency of cell replication is correlated with differences in annual/perennial habit. Since annuals have shorter minimum time to first flowering than perennials, it has been assumed that annuals would also experience a higher frequency of cell replication per chronological time and thereby a faster rate of divergence when compared to perennials [18]. The generation time hypothesis has been invoked to explain why annual species exhibited higher rates of molecular evolution than perennial species for several nuclear, mitochondrial and chloroplast loci (e.g. [19-23]). However, results from studies that support a generation time effect in plants have two primary limitations [24]. First, some studies used multiple non-independent comparisons in their analyses that may lead to statistical difficulties as well as potential phylogenetic bias. Second, the taxa compared were highly divergent so that other evolved differences in addition to generation time could also have caused the rate variation observed. Comparing divergence rates in phylogenetically-independent sets of annual/perennial pairs that are recently diverged can correct for these two pitfalls when testing for a generation time effect in angiosperms [24].

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bio_man

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