Question

Which one of the following genotypes can form only two different types of gametes?

• A. AaBbccDd
• B. AaBbccDDEe
• C. AABbCCddEE
• D. AaBbCcDDEe

Answer 1

The correct option is C AABbCCddEE

Formula to calculate how many different types of gametes can be formed is $2^n$, where n is the number of heterozygous genes/ allele pairs.
The AABbCCddEE genotype has one heterozygous gene pair of Bb, hence it will form 2 types of gametes, ABCdE and AbCdE.
AABbCCddEE produces only 2 types of gametes as shown below:
AABbCCddEE
↓
ABCdE & AbCdE
AaBbccDd forms $2^3$ = 8 kinds of gametes.
AaBbccDDEe forms $2^3$ = 8 kinds of gametes.
AaBbCcDDEe forms $2^4$ = 16 kinds of gametes.