Population genetics problems
Multiple-Choice Questions
1.
Imagine a species where there is a locus with two alleles, A and B. Further imagine that A
and B are codominant. How many different phenotypes are possible in this species?
A) 1
B) 2
C) 3
D) 4
ANS: C
2.
Imagine a species where there is a locus with two alleles, A and B. Further imagine that A
is dominant and B is recessive. How many different phenotypes are possible in this
species?
A) 1
B) 2
C) 3
D) 4
ANS: B
3.
There are two alleles for the PTC-tasting locus in humans: T, which codes for tasting, and
t, which codes for non-tasting. T is dominant and t is recessive. Imagine two parents that
are tasters have a child that is a non-taster. Given this information, you know that the
genotypes of the parents had to have been
A) Tt and Tt.
B) TT and Tt.
C) Tt and TT.
D) TT and TT.
ANS: A
4.
Imagine there is a locus with two alleles, H and h, where H is dominant and is the “hairy
nose” allele. If a man with genotype HH mates with a woman with genotype hh, the
proportion of offspring expected to have the “hairy nose” phenotype is
A) 25 percent.
B) 50 percent.
C) 75 percent.
D) 100 percent.
ANS: D
5.
Imagine there is a locus with two alleles, R and r, where R is dominant and is the “red toe”
allele. If a woman with genotype Rr mates with a man with genotype Rr, the proportion of
offspring expected to have the “red toe” phenotype is
A) 25 percent.
B) 50 percent.
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Population genetics problems
C) 75 percent.
D) 100percent.
ANS: C
6.
Assume a locus with two alleles, F and G. If a woman with genotype FG mates with a man
with genotype FG, the expected proportion of heterozygotes among their offspring is
A) 25 percent.
B) 50 percent.
C) 75 percent.
D) 100 percent
ANS: B
7.
Assume a locus with two alleles, D and d. If a man with genotype Dd mates with a woman
with genotype dd, the expected proportion of homozygotes among their offspring is
A) 25 percent.
B) 50 percent.
C) 75 percent.
D) 100 percent.
ANS: B
8.
The ABO blood group has three alleles (A, B, O). If a woman with genotype AO mates with
a man with genotype BB, the expected proportion of heterozygotes among their offspring
is
A) 25 percent.
B) 50 percent.
C) 75 percent.
D) 100 percent.
ANS: D
9.
The ABO blood group has three alleles (A, B, O) where A and B are codominant and O is
recessive. If a man with type O blood mates with a woman with type A blood, the
expected proportion of heterozygotes among their offspring is ________ depending on
the genotype of the woman.
A) 0 or 25 percent.
B) 25 or 50 percent.
C) 50 or 100 percent.
D) 75 or 100 percent.
ANS: C
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