Monohybrid Cross Problem Set

Problem 12: 2:1 segregation in Manx cats

Manx cats are heterozygous for a dominant mutation that results in no tails (or very short tails), large hind legs, and a distinctive gait. The mating of two Manx cats yields two Manx kittens for each normal, long-tailed kitten, rather than three-to-one as would be predicted from Mendelian genetics. Therefore, the mutation causing the Manx cat phenotype is likely a(n) __________ allele.

Courtesy of PETNET in Australia

A. pleiotropic

B. co-dominant

C. epistatic

D. lethal

The predicted segregation pattern in the F2 generation is 1/4 normal (homozygous), 1/2 Manx phenotype (heterozygous), an 1/4 embryonic lethal (homozygous for the Manx allele).

E. sex-linked