Question

Pea flowers may be purple (P) or white (p). Pea seeds may be round (R) or wrinkled (r). What proportion of the offspring from the cross PpRr × PpRr are expected to have white flowers and wrinkled seeds?

Answer 1

Answer:

The proportion of the offspring from the cross PpRr × PpRr that are expected to have white flowers and wrinkled seeds is 1/16 or 6.25%.

Step-by-step explanation:

The uppercase letter represents the dominant allele, while the lowercase represents the recessive allele. The dominant allele determines the phenotype (observable trait) when it is present. 

When you cross heterozygous individuals for each trait, each individual of the offspring has the probability of 1/6 of each combination of four alleles (two for each trait). Because the dominant allele determines the phenotype when it is present, the probability of dominant phenotypes is higher than recessive phenotypes.

Proportions of each phenotype in the offspring from the cross PpRr × PpRr are:

Purple flowers with round seeds: 9/16

Purple flowers with wrinkled seeds: 3/16 

White flowers with round seeds: 3/16

White flowers with wrinkled seeds: 1/16

The proportion of individuals with white flowers and wrinkled seeds is the lowest because they are homozygous recessive for both traits.