Question

Explain the cause responsible in a human to have sex chromosomes as ‘XXY’ instead of ‘XX’ or ‘XY’.

Answer 1

When chromatids fail to separate properly during cell division (nondisjunction), abnormal gametes are formed. If such a gamete participates in fertilization, the resulting male child may have an extra X chromosome, resulting in the chromosomal constitution XXY. The presence of an additional X chromosome in a male is known as Klinefelter’s syndrome.