Question

The phenotypic ratio obtained by crossing a heterozygous parent (YyRy) with a recessive parent (yyrr) is:

• A. 9 : 3 : 3 : 1
• B. 3 : 1
• C. 1 : 1 : 1 : 1
• D. None of the above

Answer 1

Answer: (C)

1 : 1 : 1 : 1

Parent 1: YyRr

Gametes: YR, Yr, yR, yr

Parent 2: yyrr, will produce all same gametes - yr

So, YyRr x yyrr:

Gametes	YR	Yr	yR	yr
yr	YyRr	Yyrr	yyRr	yyrr

Only four phenotypes will be observed in the progenies.

So, the phenotypic ratio will be 1:1:1:1

Thus, the correct answer is option C.