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Genotype Symbols for Zucchinis

You cross two true breeding strains of zucchini, one with green fruit and the other with yellow. The F1 plants are all green , but when these are crossed, the F2 plants consists of 9 green and 7 yellow. How many genes are involved in determining the zucchini color? Using your own symbols, designate which genotypes yield green and which yield yellow zucchinis.

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genotypes
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You cross two true breeding strains of zucchini, one with green fruit and the other with yellow. The F1 plants are all green , but when these are crossed, the F2 plants consists of 9 green and 7 yellow. How many genes are involved in determining the zucchini color? Using your own symbols, designate which genotypes yield green and which yield yellow zucchinis.

Solution:

Gene Interaction -complementary action:

One dominant allele of each of two genes is necessary to produce phenotype. Epistatic interactions of the genes will give a modified 9:7 ratio.

Green zucchini is crossed with yellow Zucchini strains (True breed), so the genotype will be

Green strain * Yellow strain ----- All are true breed
GGYY ggyy

GgYy --------------- Gametic condition of progeny (Green)---F1

The cross between the F1 individuals will give 9:7 ratios in F2.

GgYy * GgYy ----------F1 generation

GY Gy gY gy
GY GGYY GGYy GgYY GgYy
Gy GGYy GGyy GgYy Ggyy
gY GgYY GgYy ggYY ggYy
gy GgYy Ggyy ggYy ggyy

The F2 plants consists of 9 green and 7 yellow ...

Solution Summary

The expert examines genotype symbols for zucchinis. How many genes are involved in determining the zucchini color is determined.

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