In pea plants, the trait for purple flowers (P) is dominant over the trait for white flowers (p). If two heterozygous purple plants are crossed, what percentage of the offspring would be expected to have the same phenotype as the parents?

Answer 1

To determine the percentage of offspring with the same phenotype as the parents, we need to use a Punnett square.

Let's use the following notation:
P = purple flower allele
p = white flower allele

The parents are both heterozygous purple plants, so their genotype is Pp.

When we cross two heterozygous parents (Pp x Pp), the possible combinations are as follows:

Pp x Pp
P | p
____|____
Pp | Pp
Pp | Pp

As we can see, there are 4 possible genotypes for the offspring: PP, Pp, Pp, and pp. Out of these 4 possible genotypes, 3 have the purple flower phenotype (PP, Pp, Pp). Therefore, 3 out of 4 genotypes or 75% of the offspring would be expected to have the same phenotype as the parents (purple flowers).