Complementary gene explanation

Crossing a sweet pea with a white flower (AAbb) with another white flower (aaBB) resulted in an F1 line with purple flowers (AaBb). Self-fertilization between purple (AaBb) flowers in the F1 progeny resulted in 9 purple and 7 white flowers in the F2 progeny.

here,

The first white flower genotype is AAbb

The second white flower genotype is aaBB

The first progeny is F1 and the second progeny is F2

Parents : ♂ × ♀

Phenotype: White flowers White flowers

Genotype : AAbb aaBB

Gamit : (Ab) (aB)

F1 Lineage : AaBb (Purple)

 

Self fertilization : F1×F1

Parents : ♂ × ♀

Phenotype: Purple flowers Purple flowers

Genotype : AaBb AaBb

Gamit : (AB)(Ab)(aB)(ab) (AB)(Ab)(aB) (ab)

F2 progeny (checker board)

Comment: From the checker board, out of 16 flowers, 9 are purple and 7 are white. The purple color of the flower is due to the combined effect of expressed genes A and B.

Phenotypic ratio : Purple : White = 9 : 7

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