In cattle, the hornless gene dominates over the hornless gene.

In cattle, the hornless gene dominates over the hornless gene. What result can be expected from crossing a heterozygous bull with a homozygous hornless cow?

Let’s designate the gene responsible for the development of horns as a, then the gene for hornlessness will be A.

A heterozygous bull, Aa will not have horns, since for the manifestation of a recessive trait (horns) in the phenotype, the genotype of an individual must necessarily be homozygous (aa). Bull Aa produces two types of sperm: A and a.

A homozygous hornless cow – AA, she produces A.

As a result of crossing this bull and this cow, all their offspring will be hornless, half will be homo- (AA), and the other half will be heterozygotes (Aa).