Changes in the heritable attributes of populations of organisms over time. Major mechanisms include drift, natural selection, mutation, and gene flow (migration).

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Model for fluctuating selection

Is there any mathematical model to predict the behaviour and long-term consequence of counter-acting selection at different time scale? For example, let's consider the bi-allelic gene $A$, with ...
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Selection on linked loci in a diploid population

Let’s consider two linked loci $A$ and $B$ that are both bi-allelic. In consequence, we have four different possible haplotypes $A_1B_1$, $A_1B_2$, $A_2B_1$, $A_2B_2$, which frequencies are $X_1$, ...
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Effective population size and overlapping generations

From this book; If generations overlap, then the effective population size $N_e$ does not equal the population size $N$. I know mathematical formulations in order to find the effective population ...
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34 views

Effect of natural selection on phenotypic variance

Short background Theoretically speaking, natural selection causes a decrease in genetic variance and because the environmental variance should remain unchanged, natural selection causes a decrease of ...
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1answer
99 views

Heterozygosity and overdominance

Consider $m$ loci with heterozygote advantage (overdominance) such that the fitness of the two homozygotes is $1-\frac{s}{2}$ and the fitness of the heterozygotes is $1+\frac{s}{2}$, where $s>0$. ...
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75 views

What are the costs associated with carrying lots of genetic material

What are the costs (if any) associated with carrying lots of genetic material? energy for copying? raw material for copying? space in the cell? Maintenance cost (matter and energy)? time to copy is ...
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1answer
96 views

Population genetics and the fitness probability distribution. Why is the arithmetic mean all we need?

When recording change in allele frequency in diploid, bi-allelic, infinite and panmixic population we usually use this kind of equation: $\delta_p = \frac{p * q *( p (w11 - w12) + q * (w12 - ...
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2answers
36 views

Book recommendations for evolutionary models

I was recently working on getting a statistical model of a DNA sequence. To do this I found that understanding evolution quantitatively seems to be quite important. I would really appreciate any book ...
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1answer
34 views

Can animals distinguish other animals?

Are animals able to tell the difference between other animals. I dont mean like a cat seeing a dog and thinking "Oh no its a dog". I mean how does prey distinguish predator or threat? Say for instance ...
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1answer
77 views

Why haven't land animals evolved beyond urination?

It occurred to me (while urinating) that this would seem to be selected against because water is a scarce resource. Why are we constantly losing water we don't need to through urination? What is ...
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Unresolved polytomic Phylogenetic Tree in MrBayes [on hold]

I ran MrBayes for 1000000 mcmc generations and the phylogenetic tree which i obtained showed polytomy and was not resolved. Any suggestions as to how to correct it?
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1answer
30 views

List of heritability estimates in humans?

Many people on this site ask questions that directly or indirectly have to do with heritability in human. Do you know a list of estimates of heritability of various traits in humans? Or could you try ...
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27 views

How are new chromosomes replicated into the next generation via sexual reproduction?

If an individual has a new chromosome, which is very unlikely to happen, he will not have any luck in finding a sexual partner with this same trait. How will the offspring inherit this trait. And ...
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1answer
66 views

Opposite results between Blomberg's K and phylogenetic signal in Phylocom (AOT)

I've been trying to test for significant phylogenetic conservatism in some plant traits. So far I used R-package picante (Blomberg's K) and AOT in Phylocom. So far these two methods yield completely ...
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2answers
56 views

Can I force evolution in a group of cells by removing all the smaller cells?

I actually have algae growing in water in a container. I was thinking if it was possible to filter the water so that all the small cells will be filtered out and only the bigger ones will remain to ...
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1answer
19 views
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2answers
56 views

Book recommendation on population/evolutionary genetics?

I have recently been involved in collaborations that require me to model the population genetics of eukaryotic populations. I fear I may either be "re-inventing the wheel" or making conceptual ...
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2answers
80 views

Which was the last significant event in human evolution? What's next?

At 10.000 BC(12 ka) we became the last of the Homo species on Earth, in evolutionary terms this is a very little time range to something happen but I'm wondering ...
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1answer
24 views

Coalescent Theory - Probability for $k$ alleles that of one coalescence event occured $t+1$ generations ago

From this textbook Under the wright-Fisher model of genetic drift and under the assumption that all alleles are neutral, the probability that $k$ alleles had $k$ distinct parent alleles the previous ...
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1answer
42 views

Does recombination increase the additive genetic variance for fitness?

On this article, first column, eighth line of the introduction: By bringing together favourable alleles from different chromosomes, sex and recombination increase the additive genetic variance for ...
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1answer
64 views

How does GC-content evolve?

Background GC-content refers to the frequency of base pairs that are either C or G in the genome, or in other words the number of GC base pairs divided by the addition of the number of GC base pairs ...
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3answers
908 views

Why do parasites sometimes kill their hosts?

It's bothered me for a while now. I understand why a parasitoid would do this, as it only temporarily requires the host, and that not all parasites kill their hosts. There seems to be no evolutionary ...
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3answers
392 views

Evolution: How could all useful traits evolve simultaneously?

I have a basic question about evolution, for which I never found an answer. I understand how evolution works if we focus on one specific organ or trait. With each generation, some organism is more ...
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2answers
79 views

Heterozygosity under genetic drift

The wright-Fisher model of genetic drift is: $$p_{ij} = \binom{2N}{j}\left(\frac{i}{2N}\right)^j \left(1- \frac{i}{2N}\right)^{2N-j} $$ ,where $\binom{2N}{j}$ is a binomial coefficient. From this ...
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Evolution of Chromosome Numbers

Some species have different numbers of chromosomes, as we all know. Throughout evolution, how was a species able to survive with an extra chromosome? How was this organism able to breed successfully ...
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1answer
119 views

What is the beneficial function of IgE antibody?

Dont tell me the "function" of IgE is to cause allergy ! In whatever texts I have seen it is written that IgE is important to cause allergies but what is the beneficial function of IgE ? Why was it ...
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2answers
246 views

How does the genetic code evolve?

After looking at this question, some other questions poped in my mind. The DNA code is redundant, there are 20 amino acids for 64 possible nucleotide combinations. Therefore some amino acid are coded ...
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Book-recommendations on virus evolution [closed]

I am seeking for a good book on… Virus evolution Viral population genetics Theoretical virus evolution Mathematical modeling of virus evolution Evolution of virulence Intra and inter-specific ...
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3answers
191 views

How do we know that dinosaurs were related to lizards and/or birds?

Do we clearly know what the living closest relative of the dinosaurs are? And connected to the first question, in scientific manner how do we know these relationship between extinct species and living ...
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1answer
48 views

Additive genetic variance with $n$ loci

The genetic variance of a quantitative trait (the quantitative trait in question is fitness) can be express as the sum of two components, the dominance and additive variance: $$\sigma_D^2 + ...
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1answer
85 views

Earliest ancestor of humans who could integrate into modern society

Assuming the current model of human evolution to be correct, approximately when did the earliest ancestor of humans live, who was intelligent enough, that if raised from a young enough age, could ...
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1answer
41 views

Evolution from Mating types to different sexes

Imagine a lineage of multicellular organisms that had mating types and evolved their mating types into sexes. What are the possible mechanisms that might have brought this lineage to evolve sexes from ...
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4answers
660 views

Does pheomelanin have a useful biological function?

Melanin is a natural pigment that is categorized into two main forms, eumelanin and pheomelanin. It's well documented in the science literature that increased eumelanin levels reduces the risk of ...
5
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1answer
56 views

Disproportion in cranial nerve innervation?

The cranial nerve innervation is highly disproportionate, as far as humans are concerned. I am not sure of the advantage of being innervated by cranial nerve versus being innervated by a normal ...
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3answers
1k views

Why are there no wheeled animals?

In physics, "almost everything is already discovered, and all that remains is to fill a few unimportant holes." (See Jolly.) Therefore, on Physics SE, people are veering off into different directions: ...
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1answer
44 views

Why do different humans look different?

Although farmers appear to be able to tell their cows apart, cows look very much alike to me. And this similarity in appearance seems to be a general trail across the animal kingdom: one individual of ...
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Propagation of tool use in primates?

There are several famous cases of great apes demonstrating a surprising degree of wherewithal in communication and tool use - even monkeys can learn some tool use from each other observationally, even ...
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38 views

Book recommendation on selective breeding?

I am looking for a good book that gives a nice overview of the science and technics of selective breeding. I am particularly interested in the use of population genetics to support decision in this ...
2
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1answer
30 views

Why do the neuron pathways decussate?

I learn about the brain right now, and there are crossing of neuron pathways everywhere; in the thalamus, the medulla oblongata, the pyramidal tract... And I don't understand why? What is the reason ...
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1answer
24 views

List of the biggest companies that work in selective breeding

Looking at this question, I've been wondering, What are the biggest private companies which work in both animal and non-animal selective breeding? Let me know if Biology.SE is not appropriate for ...
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Triune brain model

I have heard about the triune brain model in biology class, but my teacher does not know much about it. What I'm curious about, is this model accepted by most of the neuroscientists, or is it just a ...
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1answer
75 views

Additive genetic variance with $n$ alleles

The genetic variance of a quantitative trait (the quantitative trait in question is fitness) can be express as the sum of two components, the dominance and additive variance: $$\sigma_D^2 + ...
6
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1answer
68 views

Hill-Roberston effects and effective population size

From this article, first page, middle of the second column: Even if harmful alleles do not become fixed, they can still reduce the efficacy of selection on neighbouring loci through a process ...
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1answer
145 views

Why does the slope of parent-offspring regression equals the heritability in the narrow sense?

Background ---- Notations and assumptions ---- let $W_{ij}$ be the fitness associated to the genotype $AiAj$. $x$ is the frequency of the allele $A1$ in the population. The frequency of the allele ...
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3answers
99 views

Fisher's Fundamental Theorem of Natural Selection

Ronald Fisher discovered what he, with humility, called the Fundamental Theorem of Natural Selection. This theorem says (in its modern terminology): The rate of increase in the mean fitness of any ...
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1answer
40 views

Life on other planets [duplicate]

first of all I'm not sure if I should post this here or in the astronomy stack. I think biologist are more likely to answer my question. To make it short: Why when looking for any sort of life on ...
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70 views

Effect on fitness of mutations

What is the distribution/probability density function (PDF) of impacts on fitness of new mutations? I very welcome any partial answer that does not give the whole PDF but just some information ...
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5answers
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How did the first self replicating organism come into existence?

When people try to explain evolution, they tell me that evolution is a cumulative result of mutations & natural section of the more superior individuals of a particular species. I think I'm fairly ...
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1answer
89 views

Cyanobacterial photosynthetic oxygen yield

I am somehow not convinced that biotic factors are solely responsible for creating 21% of atmosphere (around 40 million moles of oxygen). There may be additional issues here. Since cyanobacteria ...
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1answer
31 views

Dominance/recessivity of new mutations

What is the distribution/probability density function (PDF) of recessivity/dominance of new mutations? I very welcome any partial answer that does not give the whole PDF but just some information ...