Question
Biology Question on Principles of Inheritance and Variation
XO-chromosomal abnormality in human beings causes
A
Turner�s syndrome
B
Down�s syndrome
C
Klinefelter�s syndrome
D
none of these
Answer
Turner�s syndrome
Explanation
Solution
Turner�s syndrome is characterised by the monosomy of XO type. These are immature sterile females with webbed neck. Klinefelter�s syndrome is characterised by trisomy (XXY). These are male individuals, who are phenotypically fairly normal but have a fairly low sperm count and therefore sterile. Down�s syndrome is caused due to the presence of extra chromosome 21 (trisomy 21).