Extensions to Hardy-Weinberg Problems
1. In a population of brown trout, consisting of 300 individuals, the frequency q of a recessive allele
controlling spiny fins is 0.45. 30 fish from a different population B, where the frequency qm of the same
allele is 0.25, migrate downstream in population A.
a. What is the rate of migration?
b. What is the
q?
c. What will be the new frequency of q in population A?
2. A biologist studying the fish in the above population discovers that heterozygotic fish have frilled fins.
If there is no further migration and the population meets the requirements of Hardy-Weinberg, how
many fish with frilled fins would the biologist expect to see one generation after the migration? Assume
After one generation population A consists of 330 individuals.
3. In fact, after one generation the biologist finds that only 30% of the fish have frilled fins. He suspects
that inbreeding is the cause and calculates the inbreeding coefficient for population A. What is the
inbreeding coefficient?
4. Population A increases by 20% in one year due to migrant individuals coming from a separate
population B of the same species. The frequency of a recessive allele in population A is 0.5, while the
frequency of the same allele is population B is 0.75. What is the new frequency of this allele in
population A after one generation of random mating?