Suppose two independently assorting genes are involved in the pathway that deter

Question

Suppose two independently assorting genes are involved in the pathway that determine fruit color in squash. These genes interact with each other to produce the squash colors seen in the grocery store.

At the first locus, the W allele codes for a dominant white phenotype, whereas the w allele codes for colored squash. AT the second locus, the allele Y codes for a doinant yellow phenotype, and the allele codes for a recessive green phentoype. The phenotypes from the first locus will always maske the phenotype produced by the second locus if the dominant allele (W) is present at the first locus. This masking pattern is known as dominant epistasis.

A dihybrid squash, WwYy, is selfed and produces 180 offspring. How many offspring are expected to have eachof the following phenotypes?

Explanation / Answer

Self-cross of dihybrid squash WwYy (exhibiting epigenetic dominance), will have the offspring with the following genotypes and phenotypes.

9 W_Y_ --------> White coloured

3 W_yy ----------> White coloured

3 ww_Y ------------> Yellow coloured

1 wwyy -------------> Green coloured

The chances of having white coloured phenotype for each cross = 12/16

Thus, the chances of having white coloured phenotype in the total 60 offspring = 12* 160/16 = 120

Now, the chances of having yellow coloured phenotype for each cross = 3/16

Thus, the chances of having yellow coloured phenotype in the total 60 offspring = 3* 160/16 = 30

Now, the chances of having green coloured phenotype for each cross = 1/16

Thus, the chances of having green coloured phenotype in the total 60 offspring = 1* 160/16 = 10

Related Questions

Navigate

• Browse (All)
• Browse S
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.