4-1
Biology 22
Problems in Population Genetics
1. Albinism, a lack of skin pigmentation, is caused by the autosomal recessive
allele a. The dominant allele A causes skin pigmentation. For a particular
population, the frequency of albinos is 0.09.
a. What is the frequency of the allele for albinism?
b. What is the frequency of the allele for skin pigmentation?
c. What is the frequency of individuals with skin pigmentation?
d. What is the frequency of individuals who are homozygous for the skin
pigmentation allele?
e. What is the frequency of individuals who are heterozygous for the
albino allele?
2. Colorblindness is an X-linked recessive allele.
a. In a particular population in Hardy-Weinberg Equilibrium, 1 in 20 males
are colorblind. What is the frequency of colorblind females in this
population?
b. In a population that is not in Hardy-Weinberg Equilibrium, the
frequency of the colorblind allele is 0.1 in females and 0.7 in males.
Considering random mating to produce the next generation, what
proportion of male offspring will be colorblind? What proportion of the
female offspring will be colorblind?
c. Twenty percent of the males in a certain population are colorblind. A
representative group of 1000 migrates to a small, isolated island where
there are already 1000 individuals where 30% of the males are
colorblind. What is the frequency of colorblind males and females in
the new mixed population immediately after immigration? Assume both
populations are in Hardy-Weinberg Equilibrium at all times.
3. What is the probability of homozygosity by descent of the offspring of a
a. parent-child mating?
b. aunt-nephew or uncle-niece mating?
c. first cousin mating?