Question

You are studying a gene that controls ossicone (horn) length in giraffes. The wild-type long-ossicone allele (L) is dominant to the mutant short-ossicone (l) allele. However the L allele is only 60% penetrant. You cross two giraffes, one heterozygous and one homozygous recessive. What phenotypic progeny classes do you expect and at what frequencies (assume the penetrance of L applies equally to both homozygotes and heterozygotes).

Answer 1

0.45

(with the normal cross, Ll x Ll would predict 75% of offspring to have long ossicones, but only 60% actually expresses the phenotype ... 0.75 x 0.60 = 0.45)

Step-by-step explanation: