Which of the following assumptions does not underlie Kimura's neutral theory of molecular evolution?
a. High amounts of genetic variation segregate in natural populations.
b. Evolutionary changes at the molecular level occur at a relatively constant rate.
Advantageous mutations occur often, and many fixation events are due to positive selection.
A set of 107 experimental populations of Drosophila melanogaster were maintained at a population size of 16 individuals for multiple generations. In each population, the initial frequencies of bw75 and bw alleles were equal. After 19 generations, the bw75
both alleles are neutral, and fixation events were due to genetic drift.
FST is a measure of population differentiation. An equation exists for the equilibrium FST when the forces of drift and mutation counteract each other. Which of the following statements about this equation is false?
a. If rates of migration are high, then
Gene flow causes demes to differ, while genetic drift causes demes to be similar.
In the late eighteenth century, a typhoon swept through the Pacific atoll of Pingelap, leaving approximately 20 survivors. A large percentage of the present-day inhabitants of Pingelap are color blind. One can conclude, therefore, that the population expe
bottleneck.
Which of the following is not a reason that an effective population size can be smaller than the actual population size?
a. There are different numbers of males and females in the population.
b. Every individual produces exactly two offspring.
c. Generati
Every individual produces exactly two offspring
Which of the following is not a good explanation for why rates of molecular evolution vary between lineages?
a. Genes evolve more slowly in organisms with long generation times.
b. Mutation rates vary for organisms with different metabolic rates.
c. Natur
Natural selection acts equally on sequence variation in all parts of the genome.
A rodent species has a population in one area of 100,000 individuals, and the per-gene mutation rate is 10-6. The average heterozygosity of this population is 0.0909. Another population of the same species has twice as many individuals (200,000). Assuming
0.1667
Two alleles (A and B) segregate at a locus. Assuming that no stabilizing forces exist, the A allele will eventually be
a. fixed.
b. either lost or found.
c. preserved.
d. either fixed or broken.
e. either lost or fixed.
either lost or fixed.
Which of the following statements about genetic drift is true?
a. Mildly disadvantageous alleles can sometimes increase in frequency, due to genetic drift.
b. Evolution by random genetic drift proceeds faster in large populations than in small populations
Mildly disadvantageous alleles can sometimes increase in frequency, due to genetic drift.
Consider a hypothetical locus with two segregating alleles (A and B). Population size is small, mutation is absent, and neither of the two alleles has a selective advantage. Which of the following is likely to occur after a long period of time (many gener
The population will eventually become monomorphic for one of the two alleles.
Human mtDNA lineages coalesced over a hundred thousand years ago (156 to 250 Kya) in a putative individual who has been dubbed "mitochondrial Eve." What does this name mean?
a. The human population at the time had only one female.
b. The name "Eve" first
Other females lived at the time, but their mtDNA is absent from today's population.
Natural selection and genetic drift are the two most important causes of evolutionary change. How do they differ?
a. Only natural selection can change the frequencies of alleles in a population.
b. Genetic drift is nonadaptive; it changes allele frequency
Genetic drift is nonadaptive; it changes allele frequency without regard to fitness.
A striking conclusion of the neutral theory is that the rate of fixation of neutral mutations is equal to the mutation rate (u0). Why?
a. Different allele copies have different probabilities of fixation.
b. Mutation rates are orders of magnitude greater t
The number of new mutations in a population per generation, multiplied by the probability that any one allele copy will be fixed, is equal to u0.
A small population of three-spined stickleback fish lives in an Alaskan lake. Two alleles segregate at a neutral locus (A and B). The allele frequency of the A allele is 0.78. Which of the following allele frequencies would most likely be found in the nex
0.79
Very little genetic variation exists for populations of the northern elephant seal (Mirounga angustirostris). While 30,000 individuals exist today, in the 1890s hunting reduced the population size to about 20 individuals. What is the reason for such low g
Both a and c: The mating system of elephant seals leads to a low effective population size and the population experienced a bottleneck.