Q. Excessive growth of hair on the pinna is a feature found only in males because
A) The female sex hormone oestrogen suppresses the character in females
B) The gene responsible for the character is present on the Y-chromosomes only
C) The gene responsible for the character is recessive in females and dominant only in males
D) The character is induced in males as males produce testosterone
Explanation
Genes in the non-homologous region of Y-chromosome pass directly from male to male. In man, the Y-linked or holandric genes such as ichthyosis, hystrix, gravis hypertrichosis (excessive development of hairs on pinna of ear) are transmitted directly from father to son.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.