Principles of Inheritance and Variation Question 195
195. A person with the sex chromosomes XXY suffers from
[1997]
(a) Down’s syndrome
(b) Klinefelter’s syndrome
(c) Turner’s syndrome
(d) Gynandromorphism
Show Answer
Answer : b
Hints & Solution
(b) Down’s syndrome develops due to trisomy of chromosome number 21. In Turner’s syndrome, the effect appears due to fusion of a gamete without sex chromosome and a gamete with one $X$ chromosome (44 + $X)$. Klinefelter individuals are phenotypically males. The defect appears due to fusion of egg having unreduced sex complement $(A+$ $X X$ ) with a gamete carrying $Y$ chromosome $(44+XXY)$. Gynandromorphism occurs in Drosophila. In such individuals one half of the body shows male characters and the other half shows female characters.
