You Are Studying a Gene That Controls Ossicone (Horn) Length

Multiple Choice

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 heterozygous giraffes. What proportion of offspring would you expect to exhibit the long-ossicone phenotype? Assume the penetrance of L applies equally to both homozygotes and heterozygotes.

A) 0.40
B) 0.45
C) 0.55
D) 0.60
E) 0.75