Question

Suppose that a homozygous red horse and a homozygous white horse mate and produce a heterozygous red and white haired horse.



What was the likelihood of the parents producing a horse that is heterozygous for red and white hair and how do you know?



A.
100% because the hair color of these horses is inherited in a codominant pattern

B.
75% because the hair color of these horses follows a pattern of simple dominance

C.
50% because the hair color of these horses follows a pattern of incomplete dominance

D.
25% because the hair color of these horses is inherited in a recessive pattern

Answer 1

A. 100% because the hair color of these horses is inherited in a codominant pattern.

Explanation: If one parent is RR (homozygous red) and the other is WW (homozygous white), every offspring will receive one R and one W allele (RW). With codominance the heterozygote expresses both colors, so 100% of offspring are heterozygous and show both red and white.