question_answer

A bald headed (Bb) man marries a non-bald woman (Bb), their progeny if all are females, the probable bald to non-bald ratio in their progency would be :

A)  1 : 1                                      

B)  3 : 1

C)  1 : 3                                      

D)  2 : 1

Correct Answer: C

Solution :

                 Baldness is common in humans. It may occur due to radiation effects, thyroid irregularities and other reasons, but a particular type pattern baldness is hereditary. Hereditary baldness is carried by a dominant autosomal gene, say B. All homozygous BB are bald whether these are men or women. Similarly, homozygous (bb) men and women are always nonblads. In case of heterozygous (E: individuals, however, baldness develops only in men and never in women, because the singleton dominant gene B expresses itself only when push of male hormones is available.