The theory by which mutations in the genetic code lead to differences from the previous phenotype that, should they be advantageous to an organism's survival to reproductive age, may be passed on to offspring.

learn more… | top users | synonyms

1
vote
1answer
25 views

Definitions of robustness and canalization

The concepts of robustness and canalization are fashionable today in the biology literature. However, I am not sure of their definitions and I am not sure either that all authors actually use the same ...
4
votes
1answer
29 views

Is there an association between environmental and mutational robustness?

The robustness of a genotype is the ability of this genotype to resist (always produce the same phenotype) to various parameters such as mutations and environment. The ability of a genotype to resist ...
2
votes
0answers
6 views

Mutation-drift equilibrium and among loci variance in heterozygosity

At mutation-drift balance, the increased heterozygosity brought by new mutations is exactly equal to the loss of heterozygosity due to genetic drift. At equilibrium, the expected heterozygosity for a ...
7
votes
1answer
104 views

Fisher's Geometric Model for Dummies

Fisher's geometric model is still today one of the most important and fundamental model in evolutionary biology but it seems to me that most student in evolutionary biology don't really understand it ...
9
votes
3answers
586 views

The evolutionary process in bird wings, especially with regard to winglets

In this answer on aviation.SE a comparison is made between the shapes of airplanes wings and the shapes of birds wings. It concludes with the following remark: After all, no bird has winglets. Not ...
5
votes
1answer
28 views

Components of the concept of Developmental Noise?

Developmental noise is a concept that correspond to the amount of possible phenotypic variance of a given genotype in a given environment. Intrinsic noise (aka Cellular noise) is a component of ...
3
votes
0answers
38 views

How does Natural Selection Shapes Genetic Variation?

Background Importance of the additive genetic variance As stated here, the fundamental theorem of Natural Selection (NS) by Fisher says: The rate of increase in the mean fitness of any organism ...
6
votes
1answer
70 views

What does “Mutational Variance” mean?

Background The concept of mutational variance can be found in many articles including this one for example. The mutational variance of a trait number $i$ can be found in the M-matrix in position ...
11
votes
6answers
2k views

Is there a biological mechanism for evolution encoded into our DNA?

Throughout high school, I remember learning about Darwin's theory of evolution as if it were near-fact. But something always seemed wrong about the ideas presented. Survival of the fittest Random ...
1
vote
2answers
78 views

What is the reproductitive advantage of grey-haired humans

A vast majority of humans get at least some grey hair as they age. AFAIK this applies to both genders and all races. Presumably this means that at least some grey haired humans have noticeable ...
6
votes
3answers
347 views

What exactly does adaptive mean?

This is a quote from Dey et al 2014: Hatching asynchrony is thought to be adaptive because... What exactly does adaptive mean here? Does it mean hatching asynchrony has fitness benefits? Or does ...
2
votes
3answers
93 views

How did the horned lizard evolve?

It's a lizard that has the ability to burst blood vessels in it's eyes and shoot blood as self defense. How can this behavior be explained evolutionary? Wouldn't it mean that there had to be some ...
18
votes
4answers
2k views

Why are there species instead of a continuum of various animals?

As I understand it, various animal traits have to evolve gradually, but what happens to the species that are "neither here nor there"? To put it differently, if a species evolved from another, it did ...
2
votes
3answers
194 views

Where are the evolutionary “inbetweeners”? [closed]

The problem I've always had with evolution is the actual lack of variation between animals. More specifically, the lack of observable gradual change between species. Take for example the hammerhead ...
3
votes
0answers
51 views

Intuitive explanation for Kin- and Group- selection

It is known from theoretician in the field of kin selection that kin selection (inclusive fitness theory) and group selection are actually two sides of the same coin. In other words, these two ...
0
votes
0answers
19 views

coevolution by physical interaction between RNA sequences

There are several items that relate to the concerted evolution between pairs of sencuencias (especially structural) rRNA as a consequence of physical interaction in tertiary, or even quaternary ...
1
vote
0answers
18 views

detection of primary origin (natural selection or genetic drift) on alterations in sequences

I recently had a question about how to distinguish the origin of variations in the sequences of rRNA as to whether alterations are generated by genetic drift or natural selection. For me it has not ...
-1
votes
1answer
83 views

What is the outcome of a human population starting with only 2 individuals? [closed]

Starting with a human population N = 2, is there any way the genetic variability seen today could have come about? I don't know that much about meiosis, but isn't there a very limited number of ...
3
votes
1answer
61 views

Soft and Hard selection

Seems to me that these two sources (M. Whitlock, B. Wallace) use different definitions of soft and hard selection. M. Whitlock: Soft selection occurs when the relative fitness of an individual is ...
1
vote
2answers
128 views

On evolution statistics [closed]

This basic evolution theory question has been haunting me since childhood and I'm kind of embarrassed that I can't explain it yet: Consider a butterfly. It's wings have evolved to look like the eyes ...
1
vote
0answers
43 views

$F_{ST}$ and the genetic variance in metapopulations

From this video (21'15''), the speaker gives the following formulae in order to calculate the between and among populations genetic variance from the $F_{ST}$: $$V_{Among Pop} = 2 F_{ST}V_G$$ ...
1
vote
1answer
39 views

Distribution of fitness in wild populations

If I get out in the wild observe wild populations and measure the distribution of fitness $f(w)$ in a given population. What will I find out? Will I observe a Gaussian distribution, a Poisson ...
1
vote
1answer
45 views

What is a sex-biased gene?

How do you define a male-biased gene and a female-biased gene as they are found in the abstract of this article.
2
votes
1answer
47 views

Definition of Sexual Selection?

How do you define Sexual Selection (SS)? (One might want to subdivide SS into intra- and inter- SS to answer) Is SS clearly different from Natural Selection (NS)? Is SS nested within NS or are NS ...
1
vote
2answers
78 views

problem with natural selection [duplicate]

I fail to see how natural selection can build any kind of new functionality. New functionality in a design requires sacrificing a complex series of meanwhile useless steps before the new ...
2
votes
1answer
69 views

Two-fold cost of sex and r/K selection theory

This article cites a bunch of articles (I haven't been through them) that the effect of the two-fold cost of sex is "reduced" in stable environment or in K-selected environment. It says: [..] the ...
4
votes
1answer
162 views

Evolution and the levels of selection

Reading Okasha's "Evolution and the levels of selection" he talks about "the levels of selection problem." There is a bit of a problem with this opening chapter because, while he talks about why the ...
3
votes
3answers
136 views

Has it been enough time for evolution through simple natural selection?

Let first state that I understand natural selection. I am not asking if evolution happened. I see evolution as a fact, but I do not assume the current theory of natural selection as fact. I wonder if ...
2
votes
0answers
72 views

Is there an evolutionary explanation for depression?

Evolutionarily speaking, depression (both clinical depression and temporary sadness) is a curious phenomenon. Since being depressed is likely to increase the chance of a person with it to commit ...
0
votes
0answers
39 views

Effects of Genetic Drift on Linkage Disequilibrium

From what I understood of @Canadianer's answer here... Genetic drift randomly causes negative or positive linkage disequilibria, by changing allele frequencies through random sampling. Natural ...
2
votes
1answer
38 views

Definition of Linkage Desiquilibrium (LD)

According to wiki, linkage disequilibrium $D$ equals $$D = x_{11} - p_1\cdot q_1$$ where: $$ \begin{matrix} \text{Haplotype} & \text{Frequency}\\ A_1B_1 & x_{11}\\ ...
2
votes
0answers
25 views

Source of information on the evolution of aging/senescence

Do you know a good review (published peer-reviewed or an online course or whatever) that offers a good overview of all hypothesis explaining the various patterns linked with aging? I'd like this ...
0
votes
0answers
51 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 ...
3
votes
2answers
95 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 ...
3
votes
2answers
88 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 ...
3
votes
1answer
83 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 ...
1
vote
1answer
46 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 ...
1
vote
2answers
88 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 ...
1
vote
1answer
38 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 ...
1
vote
1answer
53 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 + ...
1
vote
1answer
87 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 + ...
0
votes
2answers
58 views

DNA adaptation in human life

Does our DNA adapt by human lifetime? Or do we have the same genetic information from birth to death? I mean: What is usually called "evolution" means "natural selection" like this: ...
1
vote
1answer
24 views

Could mating/recombination be responsible for evolution of entirely novel features?

The diploid chromosomal architecture is rather interesting. For example, because of diploidy we Humans have to mate. Of course in that sense, because diploid organisms often have mate, this has led to ...
3
votes
1answer
360 views

How do I calculate the change in allele frequency in a haploid population under selection?

From this book For simplicity, let us consider a haploid organism and assume that the frequencies of alleles $A_1$ and $A_2$ are given by $x$ and $y=1-x$, respectively. We also assume that the ...
4
votes
0answers
69 views

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 ...
4
votes
0answers
38 views

Linkage disequilibrium with $n_l$ loci $n_a$ alleles

Linkage disequilibrium $\left(D\right)$ for two bi-allelic loci is defined as: $$D=X_{11}X_{22} - X_{12}X_{21}$$ , where $X_{11}$, $X_{12}$, $X_{21}$, X$_{22}$ are the frequencies of the haplotypes ...
1
vote
1answer
100 views

Is Natural Selection like a Copy Editor?

I am stuck on a Homework Question. It says: Evaluate the following statement: “Natural selection works like a copy editor; it works only with what is already present in a population.” (Note: ...
4
votes
1answer
178 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 ...
2
votes
1answer
67 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 ...
1
vote
1answer
29 views

What indices can we use to describe fitness landscapes?

We usually talk of smooth or rugged fitness landscape. Are there any (standard) indices to measure the "structure" of fitness landscapes? For example, one might consider the mean epistatic ...