Question

Assertion : Variety of fruit colours in Cucurbita pepo is result of recessive epistasis.
Reason : In recessive epistatsis, a recessive gene at one locus enhances the expression of another gene, at a different locus.

• A. If both assertion and reason are true and reason is the correct explanation of assertion
• B. If both assertion and reason are true but reason is not the correct explanation of assertion
• C. If assertion is true but reason is false
• D. If both assertion and reason are false

Answer 1

Answer: (D)

Fruit colour of summer squash (Cucurbita pepo) is governed by a gene which produces yellow colour in dominant state $(Y)$ and green colour in recessive state $(yy)$. There is a non-pigment forming epistatic gene which in dominant state $(W—)$ produces white colour $(W-Y-,W-yy)$ while in recessive state it allows the yellow $(wwY-)$ and green $(wwyy)$ expression. This shows dominant epistasis where a dominant epistatic allele suppresses the expression of a non allelic gene whether the latter is dominant or recessive.