Q. Absence of one sex chromosome causes :

Q. Absence of one sex chromosome causes :

1. Turner’s syndrome
2. Klinefelter’s syndrome
3. Down’s syndrome
4. Tay-Sach’s syndrome

Solution :

Correct option : A Absence of one sex chromosome causes Turner’s syndrome. This disorder is due to monosomy (2n-1). It appears due to fusion of abnormal egg (22 + 0) and a normal sperm (22 + X) or a normal egg (22 + X) and abnormal sperm (22 + 0). People suffering from Turner’s syndrome have 45 chromosomes instead of 46 chromosomes. Such females are sterile as ovaries are rudimentary besides other features including lack of other secondary sexual characters.