Exam 8: Evolution in Finite Populations

Consider a population of size Nₑ with a new mutation that confers a fitness advantage of 1 + s.This new allele will be more likely to go to fixation due to selection if

In a diploid population,the threshold at which selection is likely to outweigh drift is when s (the selective advantage in this case)is

Population bottlenecks occur when

Explain why the probability of fixation of a new beneficial allele is independent of population size in Haldane's model of selection and drift.

If neutral mutations occur at the rate of 0.5 per individual per generation,the rate of neutral substitutions per generation in that population will equal

A population of fruit flies is maintained at 4000 individuals for 10 generations.During the 11ᵗʰ generation,the professor in charge of the flies forgot to buy fly food and only 100 flies survived.Estimate the effective population size of this population over the first 11 generations.

The nearly neutral theory

One consequence of genetic drift is

The inbreeding effective population size is often lower than the census size of a population because of

Consider a population of 10,000 pigeons founded by a population in which no alleles were identical by descent.After 30 generations in this Wright-Fisher population,what will the expected identity by descent be?

A researcher examines a microsatellite locus in a wild population of D.melanogaster.He finds that in a sample of 50 individuals,20 different alleles are segregating.The best explanation for the presence of all of these alleles is

How do the data in the following table support the neutral theory?

Refer to the figure above to answer the following question.Which of the following mutations to a codon is most likely to be selectively neutral?

What are the observed and expected heterozygosities in a population that has three genotypes with the following occurrences: f(A₁A₁)= 100,f(A₁A₂)= 25,f(A₂A₂)= 100.

If it takes many generations for a collection of gene copies to coalesce to a single gene copy,we can infer that

The figure above demonstrates the

If two randomly selected gene copies are sampled from a population of oak trees at a locus for which there is no selection,assortative mating,or migration,how many mutations would we expect these alleles to differ by?

The figure above illustrates the

Greater prairie chickens,large birds related to grouse,once maintained population sizes of hundreds of thousands on the North American Great Plains.As more and more of the native grassland was converted to farms,the number of greater prairie chickens declined,and the species nearly went extinct due to loss of habitat.Assume that a locus segregating for two alleles,A and a,each with a frequency of 0.5,existed in greater prairie chickens before the reduction of habitat.Further,assume that this species was fragmented into genetically isolated populations,containing very limited numbers of individuals.What effect on allele frequencies would one expect to find in the greater prairie chicken populations after the losses and fragmentation of habitat?

It's well known that different lineages experience different mutation rates,even at the same locus.Consider two species,1 and 2,that experience mutations rates of m₁ < m₂,with populations sizes of Nₑ₁ < Nₑ₂.Which species would you expect to have a lower frequency of heterozygotes at a neutral locus? Explain your reasoning.