Answer:
100% yellow fruit color, Yyww.
Explanation:
<u>Available data</u>:
- two independently assorting genes
- the W allele codes for a dominant white phenotype
- w allele codes for a colored squash
- The allele Y codes for a dominant yellow phenotype
- the allele y codes for a recessive green phenotype
- The phenotypes from the first locus will always mask 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
Epistasis means "interruption" and refers to interactions between genes located in different loci in the same chromosome. An “epistatic gene” can alter, influence, or suppress the expression of a "hypostatic gene". When the epistatic gene is dominant, the interaction is known as "dominant epistasis".
W suppresses the expression of Y and y, this means that whenever W is present, the fruit is white. If W <u>is not</u> present, the fruit color can be expressed.
So, the proposed cross in the present problem occurs between a green fruited individual and yellow fruited individual, which suggests that W is absent.
<em>Genotype for Green fruit: yyww</em>
<em>Genotype for purebred Yellow fruit: YYww</em>
Cross:
Parental) YYww x yyww
Gametes) Yw Yw Yw Yw yw yw yw yw
Punnet square) Yw Yw Yw Yw
yw Yyww Yyww Yyww Yyww
yw Yyww Yyww Yyww Yyww
yw Yyww Yyww Yyww Yyww
yw Yyww Yyww Yyww Yyww
F1) 100% Yellow fruited plants, Yyww
As these two genes assort independently, we can also represent the cross for each gene by separate, like this:
For w gene:
Parental) ww x ww
Gametes) w w w w
Punnet square) w w
w ww ww
w ww ww
F1) 4/4 or 100% colored-fruits
For Y gene:
Parental) YY x yy
Gametes) Y Y y y
Punnet square) Y Y
y Yy Yy
y Yy Yy
F1) 4/4 or 100% yellow fruits, Yy.
