Question

Which of the following condition in recessive duplicate epistasis will give the odd phenotype?

(a) A/- B/-

(b) A/- b/b

(c) a/a B/-

(d) a/a b/b

The question was asked in an internship interview.

The query is from Duplicate Epistasis topic in division Extension and Deviation from Mendelian Genetic Principles of Cytogenetics

Answer 1

The correct choice is (a) A/- B/-

The best explanation: Only when atleast one dominant allele is present in both the locus we get the expression of dominant phenotype. Otherwise the resulting cases give only recessive phenotype.