Question

What is aneuploidy? Name a chromosomal disorder in humans caused due to (a) gain of an autosome, and (b) loss of a sex chromosome in females. [2 marks]

Answer 1

Aneuploidy is the failure of segregation of chromatids during cell division cycle which results in the gain or loss of a chromosome(s). [1 mark]

(a) Down’s syndrome is a chromosomal disorder in humans caused due to the gain of autosome, an extra copy of chromosome 21 (trisomy in chromosome 21). [0.5 mark]

(b) Turner’s syndrome is a chromosomal disorder caused due to the loss of a sex chromosome (X chromosome) in females (45 with X0). [0.5 mark]