Question

In a cross with double recessive (rryy), the formed progeny had genotypes as RrYy and riYy. What is the expected genotype of unknown hybrid used in the cross? (A) RiYy (B) mYy (C) myy (D) RrYY​

Answer 1

Expected genotype of unknown hybrid used is RiYy

Explanation:

• It is given that one of the parent genotype is rryy .
• For the progeny or F1 to be RrYy and riYy , one of the other parent genotypes should be RiYy .
• This is because according to Mendelian double hybrid cross, when rryy crosses with RiYy , alleles formed will be ry , RY , Ry , iY and iy .
• Now when ry crosses with RY , we get RrYy and when iY crosses with ry , we get riYy, which are the given F1 genotypes.
• Therefore correct option is (A) .