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I think one of the important things to understand in thinking about this case is that it just hasn't been that long, generationally. Escobar imported the hippos in the late 1980s. Hippos reach sexual maturity at an average of about 7.5 years old for males and 9.5 years for females, space births about 2 years apart, and live for 40-50 years. Thirty years out,...


8

They often do. You hear a lot about all of the times invasive species succeed in invading a new habitat, because there is a surviving population around for researchers to observe. There are lots of cases where new species are introduced to an environment in a single event but fail to survive. Rabbits and foxes were repeatedly introduced to Australia, only ...


7

There are some references on this: Castelblanco-Martinez, 2021 is a recent one. There doesn't seem to be much doubt at least that hippopotami are thriving as an invasive species. I didn't see anything on the genetics, but I will give in to the temptation to speculate even if perhaps I shouldn't. There are some advantages that are likely working against the ...


6

To focus on the inbreeding: Inbreeding in itself is not a factor that would make species die out. Rather, inbreeding increases the risk of genetic diseases, if the deleterious alleles are already present. Three females do not represent such a large genetic pool, so that inbreeding would still occur. Given that there have been only few generations since the ...


5

I think that many of the applications that you mention require wildly different numbers of individuals. It would help to know more about goals, questions, organism details, etc. For example, for simple population statistic estimates, you can depend on the large number of sites in the genome to get an accurate estimates (such as Watterson) from a single ...


4

I don't think it's a terribly rigorous statistical argument, so much as a toy model arguing that there can be a reproductive advantage to selfing in an outcrossing population. Here is the logic as I see it: Ovule and pollen represent the female and the male reproductive gametes in a monoecious plant (monoecious means that it has both male and female ...


4

It is possible to perform gene-level population genetics analyses on microbiome-derived bacterial species.1,2 † However, the biology of bacteria and the nature of metagenomic sequencing data make such analyses difficult and intractable to many of the well-worked tools of population genetics. Here are some of the things you should keep in mind as you build a ...


3

I will answer this as best as I am able, the updates are helpful for providing context. I'll also note that there are several questions packed in here, which makes it a bit more laborious to answer. I am going to try to answer the following questions: How can I infer selection on microbiota within single hosts (patients)? How can I resolve genomes of ...


3

Thank you for asking such a well-thought out question, I really enjoyed how hard this made me think about the concept. I think there might be an issue here that's quite common to biology, in my experience- poor definition of terminologies. I think the core question can be summed up by your comment: I thought dominance was only related to which phenotype ...


3

Let $\theta = 4n\mu$, then $E(S) = \theta\sum\limits_{i=1}^{k-1}\frac{1}{i}$, assuming infinite sites model. This is indeed given by Watterson (1975).


3

Minimum number of individuals needed to start a population But could just one woman be the progenitor of a healthy nation? And, if not, what is the minimum number of distantly-related individuals required? Healthy is a pretty subjective term, and it's perhaps easier to think of things in terms of a minimum viable population, which is more about straight ...


2

Has interest in haplotype blocks waned over the decade? No. You can set a time range on Google Scholar, which the screenshot shows was not done. I did that and: A search for ‘haplotype block’ from 2000 to 2009 gives 22,000 hits. A search for ‘haplotype block’ from 2000 to 2009 gives 25,700 hits. (The term haploblock is now often used as an abbreviation, ...


2

I believe that you are talking about "multidimensional selection". E.g. you are selecting on not one trait (yield) only but more than one (yield+some other trait). There's quite a bit of work done on this in crop science for example. See e.g. here here here Figure 3 from the last talks about this in terms of evolution by reproductive isolation, ...


2

I can't think of a more succinct way to phrase it than the explanation in your post. "...the genotype frequencies of the next generation depend only on the allele frequencies of the current generation..." The genotype frequencies still do depend on the initial generation, they just depend on the allele frequencies of the previous generation, not ...


2

Although I cannot find the Scientific American article to which the poster refers, I assume that the “historic human population size” is the size of the human population in Africa before it underwent the expansion that accompanied the emergence from the African continent. Some important papers on this subject were published in the late 1990s (somewhat later ...


2

A significance test (i.e., p-value) allows us to reject the null hypothesis, but not to confirm it. In other words, when $p<0.05$ one can say that the conditions for HWE are not met, however $p>0.05$ does not mean that HWE holds - the conditions might still not be met, but we cannot prove it. Thus, by making statements such as All of the SNPs didn't ...


2

Short answer: yes, people have formulated ways to estimate $F_{ST}$ for multiallelic loci, e.g. microsatellites. For a review, see here. Specifically, Nei could define $F_{ST}$ for multiple alleles as $F_{ST} = \frac{(H_t - H_s)}{H_t}$, which is to say the proportion of total heterozygosity that is across rather than within populations. This is agnostic to ...


2

Yes, in neutral theory of evolution this is called fixation - when all the alleles (for a given locus) become identical. Note that it may happen, even if the gene does not have a striong selective advantage - due to the random effects. If you are looking for the basic background in population genetics, Gellespie's book is a good starting point.


2

Animals don't die out from any causes related to themselves, their breeding, or anything like that. They die out either because their ecological niche goes away (climate change, etc.), because something else outcompetes them in that ecological niche (introduced fish outcompeting cichlids, for example), or because an external force exterminates them (...


1

Some individuals being unfit to survive, doesn’t necessarily lead to extinction, it leads to removing the traits that make them unfit to survive from the breeding pool. From a species POV this is a good thing. This leading to extinction happens when so many individuals have the trait, that those without it can’t can’t find a breeding partner to have ...


1

It depends on whether mutation exists. Generally mutation is happening in biology, but in its absence, yes it will be at or near zero: Note that in the absence of any mutation, $F_{ST}$ would be defined but equal to 0, as all the genetic variance is within individuals and none between individuals and subpopulations. From that paper, see this figure: So, ...


1

Yes. between individuals: https://academic.oup.com/mbe/article/34/2/419/2528250 between individuals: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4617969/ hypermutation (transient): https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1087688/


1

The definition as set by Kenneth Lange's book is indeed quite vague and thus unrigorous. It is a probability not conditioned on observing an allele $a$ at a locus of $i$ but conditioned on the following where we focus on one particular locus. It is rigorously defined as follows. Then we will give the correct formulation of the correct recursive equation akin ...


1

The definition of IBD is always the same - an allele or segment of alleles which is shared between two individuals because of descent from a common ancstor. In the context of this paper, the authors are referring to segments of the genome between individuals which are IBD. In this case, they are looking at recently isolated populations who are likely to ...


1

This question seems to be about negative/purifying selection, judging by the wikipedia quote. Positive selection can often (but not always) occur more slowly in smaller populations, but 'efficiency/effectiveness' of selection generally means the rate at which deleterious variants are purged from the population, so I'll skip out taking about positive ...


1

I ended up writing directly to Joe after not getting an outside answer here. I won't directly quote him without his permission, but to sum up, he wrote the following: This paper (among others) gives an numerical treatment of different selection coefficients in small populations, which effectively means loci that are not under selection but still have ...


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I know this question is a bit old, but I read a paper recently which (claimed) to answer this question. I think the answer to this question is suprisingly controversial. I don't really have a formed opinion yet of which answer is correct, but I will try to discuss the different viewpoints here. Argument 1: Sweeps are rare On one hand, we have the people who ...


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