Question

A male human is heterozygous for autosomal genes A and B and is also hemizygous for hemophilic gene h. What proportion of his sperms will be abX^h?

• A. $\frac{1}{32}$
• B. $\frac{1}{16}$
• C. $\frac{1}{4}$
• D. $\frac{1}{8}$

Answer 1

The correct option is D $\frac{1}{8}$

Hemizygous genes are genes that are present in a single copy instead of the customary two copies. All the genes on the single X chromosome in the male are hemizygous.
Additionally, hemophilia is an X- linked disorder.
Therefore if a male human is hemizygous for hemophilic gene h, then his genotype is X^hY.
Also, it is mentioned that the male human is heterozygous for autosomal genes A and B.
Therefore, the genotype for the male human is AaBbX^hY.
Different type of gametes produced by this male are,
- abX^h
- aBX^h
- abY
- aBY
- AbX^h
- ABv
- AbY
- ABY
Therefore, the proportion of sperm with abX^h chromosome is 1/8th.