Q. Fruit colour in squash is an example of :
(a) Inhibitory genes
(b) Recessive epistasis
(c) Dominant epistasis
(d) Complementary genes
Solution :
Correct option : C A dominant epistasis is a condition when a dominant gene masks the effect of the other non-allelic gene. In summer squash, the fruit color may be white, yellow, or green. White fruits are produced by a domain epistatic allele ‘W’. At another locus, Y for yellow fruits is dominant to its allele y for green fruits. Dominant white hides the effect of yellow or green. A consequence of this dominant epistasis is that the hybrid ratio is modified into 12 white: 3 yellow: 1 green. So, dominant epistasis suppresses the expression of a non-allelic gene (dominant or recessive).
Thus, the correct answer is option C.
