Question

You cross two heterozygous disc shaped squash. What will be the ratio obtained?

(a) 1:2:1

(b) 3:1

(c) 9:3:3:1

(d) 9:6:1

The question was posed to me during an interview.

My question comes from Gene Interactions topic in division Extension and Deviation from Mendelian Genetic Principles of Cytogenetics

Answer 1

The correct choice is (d) 9:6:1

To explain: Here you expect to see a deviation from the normal dihybrid ratio as two genotypes yield the same phenotype. Thus the A/- bb and aa B/- give spheres in 6/16^th of the progeny.