Genetic question

[299678]

Advertisement - Members don't see this ad

A = big apples; R = red apples; a = small apples; r = yellow apples. You have one tree that produces big yellow apples and another tree that produces small red apples. When the two are crossed, you find that half of the new trees produce big red apples and half produce big yellow apples. What are the genotypes of the parents?

AArr and aaRr
Aarr and aaRr
AARr and Aarr
AaRr and AaRr
AaRr and aarr

 

[typhoonegator]

Well, only the first two options satisfy the stated phenotypes of the parents, so that narrows it down. The answer is:

AArr and aaRr

That way, all the offspring are big, and half will be red.

This is assuming a recessive model with complete penetrance.