Exam 8: Evolution in Finite Populations

At how many generations back do all of the alleles in the current population coalesce to a single allele?

Imagine that,of three species,it is known that species 1 and 3 were separated 10 million years ago,based on geologic measurements.Genetic analysis at a neutral locus indicates that these species differ by 100 substitutions.If there are 10 substitutions separating species 1 and 2,approximately how long ago did these species diverge?

Population bottlenecks can lead to the fixation or loss of alleles in otherwise large populations because the bottleneck

A founder event changes allele frequencies because

Consider a population with a constant size,Nₑ = 5000,that experiences a mutation rate of 0.00005,with an initial F value of 0.15.What is the probability that two alleles selected at random from the offspring of this population will be identical by descent?

How are the neutral theory of molecular evolution and the Hardy-Weinberg equilibrium similar?

The neutral theory of molecular variation posits that most

A rancher genotypes all of her 150 head of cattle.In her herd,25 are A₁A₁,75 are A₁A₂,and 50 are A₂A₂.Assuming there is random mating,no selection,no mutation,and no new cattle are introduced into the population,what is the probability that the A₁ allele will be fixed?

Which of the following graphs depicts the group with the largest populations? Explain your reasoning.

The figure below presents the genotypes of individuals in several island populations at three points in time (t = 0,t = 4,t = 32).What effect of genetic drift does this figure demonstrate?

The variable F is

The molecular clock has limited usefulness for estimating divergence times among species because of

In which of the demographic patterns in the figure below would you expect the final coalescent event to be most recent? Explain your answer.

Please describe the allele substitution rate in terms of the effective population size (Nₑ),the number of neutral loci in the population (k)and mutation rate (n).Please show all of your work.

Consider a collection of 50 distinct alleles,each at equal frequency in a population.The time before the first coalescent event will be shortest if

The substitution rate is expressed in terms of substitutions per generation; however,molecular clock estimates show that substitutions accumulate annually regardless of the generation time.What explanation for this discrepancy is illustrated in the figure below?

The ancestor to the Hawaiian crickets in the genus Laupala originally colonized the oldest of the islands in the Hawaiian archipelago.As new islands were formed,crickets from the older island would colonize the younger island.Because members of this genus are flightless,these migration events were likely to be extremely rare and would include a small number of migrants.Nonselective differences in allele frequencies in this genus are likely due to

Consider a population with an effective size of 4000 and 32 segregating alleles.On average,how many generations would it take for all 32 alleles to coalesce to a single,ancestral allele?