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White fruit color in summer squash is governed by a dominant gene (W) and colore

ID: 190192 • Letter: W

Question

White fruit color in summer squash is governed by a dominant gene (W) and colored fruit by its recessive allele (w). Yellow fruit is governed by an independently assorting hypostatic gene (Y) and green by its recessive allele (y). When dihybrid plants are crossed, the offspring appear in the ratio of 12 white : 3 yellow : 1 green. What fruit color ratio is expected from the cross of WwYy to green?

a.

all white

b.

1/2 white, 1/2 yellow

c.

1/2 white, 1/2 green

d.

1/2 white, 1/4 yellow, 1/4 green

e.

1/4 white, 1/2 yellow, 1/4 green

Explanation / Answer

WwYy x wwyy

Possible gametes for WwYy - WY, Wy, wY, wy

Possible gametes for wwyy - wy

From the above, we can determine the phenotypic ratio as 2 white : 1 yellow : 1 green, or represented alternatively as 1/2 white, 1/4 yellow, 1/4 green

Option d. is the correct option

WY Wy wY wy wy WwYy (white) Wwyy (white) wwYy (yellow) wwyy (green)