Question

How many different types of genotypes are formed in the second generation of a cross between a homozygous dominant parent and a homozygous recessive parent?

• A. 1
• B. 2
• C. 3
• D. 4

Answer 1

Answer: (C)

3

This question can be solved with the help of a cross between a homozygous tall pea plant (TT) and a homozygous dwarf pea plant (tt).

Gametes	T	T
t	Tt	Tt
t	Tt	Tt

So, all the F1 progeny will have tall pea plants (Tt), since tallness (T) is the dominant trait.

On self-fertilizing the F1 progeny:

Gametes	T	t
T	TT	Tt
t	Tt	tt

3 different genotypes are obtained: TT (tall), Tt (tall), tt (dwarf).

So, the correct answer is option C.