Q. Consider the following statements:
1.Down’s syndrome results in the gain of extra copy of chromosome 21.
2.Turner’s syndrome results due to loss of an X chromosome in human females.
Which of the statements given above is/are correct?

[A] 1 only

[B] 2 only

[C] Both 1 and 2

[D] Neither 1 nor 2

Answer: C
Notes:

Explanation: Failure of segregation of chromatids during cell division cycle results in the gain or loss of a chromosome(s), called aneuploidy.

  • For example, Down’s syndrome results in the gain of extra copy of chromosome 21.
  • Similarly, Turner’s syndrome results due to loss of an X chromosome in human females.

Source: Science NCERT