Question

In pea plants, flowers are either white or purple; the purple color is produced by pigments called anthocyanins. The production of anthocyanins is a two-step process: the first is controlled by the C gene and the second by the P gene. Both genes must produce functional proteins for anthocyanin to be expressed. For each gene, the dominant (C and P) alleles produce functional proteins. You cross two pea plants, each with the genotype CcPp. What proportion of their offspring will have white flowers?

Answer 1

Answer:

7/16

Explanation:

The proportion of the offspring from the cross that will have white flowers is 7/16.

The presence of anthocyanin which determines purple coloration is conditioned by the C_ and P_ alleles. It means that the absence of one or both of C and P will result in white flowers.

Two plants, each with CcPp are crossed:

CcPp   x   CcPp

Offpring

1 CCPP - purple

2 CCPp - purple

2 CcPP - purple

4 CcPp - purple

2 Ccpp - white

1 CCpp - white

1 ccPP -  white

2 ccPp - white

1 ccpp -  white

Proportion of offspring with white flowers = 7/16

Proportion of offspring with purple flower = 9/16

See the attached image for the Punnet's square analysis of the cross.