In cattle,consider that the lack of horns is dominant to the presence of horns.A bull without horns is crossed with a horned cow.Of four offspring,one is horned and the other three lack horns.The bull is
A)homozygous dominant.
B)homozygous recessive.
C)heterozygous.
D)sex-lined recessive.
E)heterozygous recessive.

Question

Quizplus · Accepted Answer

The fact that one of the offspring is horned indicates that the bull cannot be homozygous dominant (AA), as in that case all offspring would lack horns. The fact that three of the offspring lack horns indicates that the bull cannot be homozygous recessive (aa), as in that case all offspring would also lack horns. Therefore, the bull must be heterozygous (Aa) and the horned offspring must have inherited the recessive allele from the bull's heterozygous genotype.

In Cattle,consider That the Lack of Horns Is Dominant to the Presence