Question

In another cross, a yellow seeded plant was crossed with another yellow seeded plant and it produced offspring of which about 25% were green seeded plants.

What are the genotypes of both parents?

Answer 1

In this case, we can use a Punnett square to determine the probable genotypes of the parents.

Let's use Y to represent the dominant yellow seed allele and y to represent the recessive green seed allele.

We know that the offspring had a 25% chance of being green seeded, which means that both parents must have been heterozygous for the trait.

We can set up a Punnett square with Yy x Yy:

Y y

Y YY Yy

y Yy yy

As you can see, there is a 25% chance of getting a yy genotype (green seeded) in each offspring. Therefore, both parents must have been Yy (heterozygous) for the seed color trait.