You have a collection of tomatoes generated from a mating of

You have a collection of tomatoes generated from a mating of two prized tomato strains; half of the offspring are yellow and the other half are red. What are the genotypes of the parents used to make your little baby tomatoes? Make sure you define your alleles and explain your answer.

Solution

You have a collection of tomatoes generated from a mating of two prized tomato strains; half of the offspring are yellow and the other half are red. What are the genotypes of the parents used to make your little baby tomatoes?

Assume that the gene coding for red phenotype is A and the gene coding for yellow phenotype is a; A is dominant over a. Cross between the heterozygous Aa (red) strain and the homozygous yellow strain (aa) will have the progeny with the following phenotypes:

Aa*aa -à Aa (1/2, red), aa (1/2, yellow)

Thus, the genotypes of the parents are, Aa and aa.