Question

Which of the following conditions represents a case of codominant genes?

• A. A gene expresses itself, suppressing the phenotypic effect of its alleles.
• B. Genes that are similar in phenotypic effect when present seperately, but when together interact to produce a different trait.
• C. Alleles, both of which interact to produce a trait, which may or may not resemble either of the parental types.
• D. Alleles, each of which produces an independent effect in a heterozygous condition.

Answer 1

Answer: (D)

Alleles, each of which produces an independent effect in a heterozygous condition.

Codominance is the phenomenon when the two alleles of a gene neither show dominant-recessive relationship nor show intermediate condition, but both of them express themselves independently in the heterozygous condition. This has been reported in roan coat colour of cattle (i.e., patches of 2 different colours on the skin).