In sweet pea, red flower color is controlled by two genes involved in the anthocyanin pathway, A and B. Both genes are required for expression, so that a recessive pair of alleles at either locus would result in a pink phenotype. If an AaBb plant were allowed to self-cross and you got only red and pink flowers, what dihybrid ratio would you expect in the offspring?

Question

Biology

Arely Valenzuela

22 March, 13:55

In sweet pea, red flower color is controlled by two genes involved in the anthocyanin pathway, A and B. Both genes are required for expression, so that a recessive pair of alleles at either locus would result in a pink phenotype. If an AaBb plant were allowed to self-cross and you got only red and pink flowers, what dihybrid ratio would you expect in the offspring?

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Answers (1)

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Kathy Moyer · Answer 1

The dihybrid ratio we expect in the offspring is 9:7.

Explanation:

This is an example of complementary gene interaction, which is the non allelic interaction or genes, where the prominent genes at heterozygous loci may complement each other by complementing recessive alleles at the respective loci.

So in this case of complementary gene interaction, the individuals that are A-bb or aaB - or aabb will have the same set of observable features (phenotype) but only A-B - individuals will how the dominant phenotype.