question_answer

In short homed cattle, genes for red (R) and white (r) coat colour occur, cross between red (RR) and white (rr) produced (Rr) roan. This is an example of:

A)  incomplete dominance

B)  codominance

C)  complementary genes

D)  epistasis

Correct Answer: B

Solution :

When in \[{{F}_{1}}\]  generation both the genes express themselves this is called law of codominance.                 Incomplete (mosaic or partial) dominance is the phenomenon where none of the two contrasting alleles or factors is dominant and the hybrid or \[{{F}_{1}}\]  individual is a fine mixture of the expression of two factors. Epistasis is the phenomenon of masking or suppressing the expression of a gene by another non-allelic gene. Complementary genes are those nonallelic genes which independently show a similar effect but produce a new trait when present together in the dominant form.