Evolution__3rd_Edition

154 PART 2 / Evolutionary Genetics
Study and review questions
1 A population of 100 individuals contains 100 A genes
and 100 a genes. If there is no mutation and the three
genotypes are selectively neutral, what would you expect
the genotype and gene frequencies to be a long time, say
10,000 generations, in the future?
2 Review: (a) the meaning of “random” in random
sampling, and the reason why drift is more powerful in
smaller populations, and (b) the argument why all the
genes at any locus (such as the insulin locus) in the
human population are now descended from one gene in
an ancestral population some time in the past.
3 What is the heterozygosity (H) of the following
populations:
Genotypes
Population AA Aa aa H
1 25 50 25
2 50 0 50
3 0 50 50
4 0 0 100
4 If the neutral mutation rate is 10 −8 at a locus,
what is the rate of neutral evolution at that locus
if the population size is: (a) 100 individuals, or
(b) 1,000 individuals?
5 What is the probability in a population of size N
that a gene will combine (a) with another copy of itself
to produce a new individual, and (b) with a copy of
another gene?
6 Try to manipulate equation 6.2 into 6.3 and
equation 6.6 into 6.7.
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