Question

Tail length in dogs is typically determined by incomplete dominance. Dogs with one long-tailed allele and one short-tailed allele have medium-length tails.

A dog that is heterozygous mates with a dog that is homozygous for a long-tail. What are the chances that their offspring will have a medium-length tail?

A
0%
B
50%
C
75%
D
100%

Answer 1

Answer: B) 50%

Explanation: Let L = long allele, S = short allele. Cross LS (heterozygote) × LL (homozygous long). Gametes: LS parent gives L or S (50/50), LL parent gives L only. Offspring genotypes: 50% LL (long), 50% LS (medium). So 50% have medium-length tails.