Question

Baldnesss in humans is a sex influenced trait and the gene is carried on autosomes. If both the parents are heterozygous for this gene, what will be the probability of non-bald sons and non- bald daughters respectively?

• A. $\frac{1}{4},\frac{1}{4}$
• B. $\frac{3}{4},\frac{1}{4}$
• C. $\frac{3}{4},\frac{3}{4}$
• D. $\frac{1}{4},\frac{3}{4}$

Answer 1

The correct option is D $\frac{1}{4},\frac{3}{4}$

Baldness is sex influenced trait. Sex influenced traits are autosomal traits that are influenced by sex. The allele for bald condition is B and non-bald condition is b.
BB, Bb males are bald and bb males are non bald.
But, BB females are bald and Bb, bb females are non bald.

Heterozygous parents (Bb X Bb ) produce $\frac{3}{4}$ bald sons and $\frac{1}{4}$ non-bald sons and $\frac{3}{4}$ non-bald daughters and $\frac{1}{4}$ bald daughters.