Chapter: Inheritance and Variation· Biology

The type of gene interaction deviating from Mendel’s findings of 3 : 1 to 1 : 2 is _____.

Q.1 (v) The type of gene interaction deviating from Mendel’s findings of 3 : 1 to 1 : 2 is _____.

A. Incomplete dominance

B. Codominance

C. Multiple alleles

D. Pleiotropy

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Answer: (d) Pleiotropy

In pleiotropy a single gene affects several traits. In sickle-cell anaemia the gene Hb^S is lethal in the homozygous condition (Hb^SHb^S individuals die), so a cross between two carriers (Hb^AHb^S) gives normal (Hb^AHb^A) and carrier (Hb^AHb^S) survivors in the ratio 1 : 2 instead of 3 : 1. (Incomplete dominance and codominance modify 3 : 1 to 1 : 2 : 1.)

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The type of gene interaction deviating from Mendel’s findings of 3 : 1 to 1 : 2 is _____.

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