Question

What is the expected segregation ratio for the genotypes AA, Aa, and aa from a monohybrid (Aa) self cross if all mating occurs among the products of a single meiosis?

A.

2:1:2

B.

1:1:1

C.

1:2:1

D.

1:3:1

E.

1:4:1

Answer 1

Answer :

C. 1:2:1

The self cross between two monohybrids (Aa) demonstrates classic example of Mendelian Inheritance. It can be illustrated by the following diagram:

Monohybrid Cross: (Heterozygous genotype=Aa)

		Dominant Allele	Recessive Allele
		A	a
Dominant Allele	A	AA	Aa
Recessive Allele	a	Aa	aa

As displayed above, the expected segregation ratio for the genotypes AA, Aa, and aa in the monohybrid cross will be ,

1 (homozygous dominant, AA) : 2 (heterozygous, Aa) : 1 (homozygous recessive, aa).