Question

suppose that the covering on corn kernels can have a purple color due to the dominant allele p of gene 1. the genotype pp leads to a colorless covering. alleles of gene 2 can modify the purple color, with the dominant allele r having no effect but genotype rr changing the purple color to red. alleles of gene 2 have no effect on plants with genotype pp for gene 1. for the cross pprr x pprr, what fraction of the plants are expected to have red covering on their corn kernels?

Answer 1

The cross pprr x pprr can be represented by a Punnett square as follows:

| | p | p |
|---|---|---|
| r | prr | prr |
| r | prr | prr |

All offspring have the genotype prr, which means they all have red kernels.

Therefore, the fraction of plants expected to have red covering on their corn kernels is 1 or 100%.