Question

Non-disjunction involving the X-chromosome may occur during oogenesis and produce two kinds of eggs. If normal sperm fertilize these two types, which of the following pairs of genotypes are possible?

a. XX and XY
b. XXY and XO
c. XYY and XO
d. XYY and YO

Answer 1

Answer:

The correct answer will be option-B

Explanation:

Non-disjunction is the process of the failure of the separation of the homologous chromosomes during cell division which could be observed during the meiosis I, meiosis II or mitosis.

If Non-disjunction takes place during the oogenesis then the resultant cells will be formed with XX and O gametes.

When a normal male sperm with XY fertilizes the cells then they will form four combinations:

1. XX  + X = XXX

2. XX + Y  = XXY

3. O + X = XO

4. O + Y = YO

Thus, in the given question option-B is the correct answer.