Chapter 21, Problem 23P

A mouse mutation with incomplete dominance (t = tailless) causes short tails in heterozygotes (t⁺ /t). The same mutation acts as a recessive lethal that causes homozygotes (t/t) to die in utero. In a population consisting of 150 mice, 60 are t⁺ /t⁺ and 90 are heterozygotes.

a.	What are the allele frequencies in this population?
b.	Given that there is random mating among mice, no migration, and no mutation, and ignoring the effects of random genetic drift, what are the expected numbers of the different genotypes in this next generation if 200 offspring are born?
c.	Two populations (called Pop 1 and Pop 2) of mice come into contact and interbreed randomly. These populations initially are composed of the following numbers of wild-type (t+ /t+ ) homozygotes and tailless (t+ /t) heterozygotes:

 

What are the frequencies of the two genotypes in the next generation?