Question

Two heterozygous purple-flowering pea plants are crossed. If purple is dominant over white, what are the expected phenotypic results?

Answer 1

To solve this question, one can make use of a punnet square to determine the phenotypic ratios:

A - allele for purple colour
a - allele for white colour

Aa X Aa
Genotypes: 1 AA : 2 Aa : 1 aa
Phenotypes: 3 Purple flowered pea plants to 1 white flowered pea plant.

Assuming that this complete dominance, where the A allele, the purple colour is dominant over the lowercase a allele that codes for white colour in the pea plants.

Answer 2

75% purple, 25% white.Doing the Punnett square will show that 1/4 will be PP and 1/2 will be Pp, so 75% will be purple. The last 25% (pp) will be white.