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 abh

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

Answer 1

Answer: (D)

$\frac{1}{8}$

Answer 2

Haemophilia is a recessive disorder linked to the X chromosome. In this context, males possess one X and one Y chromosome. According to the given information, a male is heterozygous for 'A' and 'B' genes but hemizygous for the haemophilic 'h' gene, resulting in the genotype AaBbXhY.The X-chromosome carries the 'h' gene, while the Y chromosome lacks this haemophilic gene because it is exclusively associated with the X chromosome. From this genotype (AaBbXhY), various gametes (sperm) can be produced, including abXh, abY, ABXh, ABY, AbXh, AbY, aBXh, and aBY. Among these possibilities, only one of the eight gametes carries the abXh combination.Therefore, the percentage of male gametes (sperm) carrying the abXh combination is 12.5%, as indicated by option A.