Question

In a species of fish, red scales (RR) and yellow scales (YY) are codominant. When a fish has the hybrid genotype, it has a patchwork of red and yellow scales. (Use the letter R and Y in your answers below).a. What is the genotype for completely red fish?b. What is the genotype for completely yellow fish?c. What is the genotype for patchwork fish?

Answer 1

Codominance

It is a non-mendelian model where, in the heterozygous state there is no recessive allele but both alleles behave as dominant, where both characteristics are manifested without mixing with each other.

In this particular case:

a. The genotype for a completely red fish would be RR (two red alleles), red homozygous.

b. The genotype for a completely yellow fish would be YY (two yellow alleles), yellow homozygous.

c. The genotype for a patchwork fish would be RY (one red allele and one yellow allele), heterozygous.