Question

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

Options

• Incomplete dominance

• Codominance

• Multiple alleles

• Pleiotropy

Answer 1

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

Explanation:

• Pleiotropy occurs when a single gene controls two or more unrelated traits.
• In the case of sickle-cell anemia (a pleiotropic trait), the phenotypic ratio deviates from Mendel’s expected 3 : 1 to 1 : 2.
• This specific deviation happens because the recessive homozygotes (those with the genotype Hb^S Hb^S) die, leaving only the healthy individuals and the carriers in a 1 : 2 ratio.