Question

A gene showing codominance has

• A. alleles that are recessive to each other
• B. both alleles independently expressed in the heterozygote
• C. one allele dominant on the other
• D. alleles tightly linked on the same chromosome.

Answer 1

Answer: (B)

The phenomenon of expression of both the alleles in a heterozygote is called codominance. The alleles which do not show dominance-recessive relationship and are able to express themselves independently when present together are called codominant alleles. As a result the heterozygous condition has a phenotype different from either of homozygous genotypes, e.g., alleles for blood group A (IA) and for blood group B (IB) are codominant so that when they come together in an individual, they produce blood group AB. height - Tall (T) - Dwarf (t)