Question

Recessive characters are expressed in the subsequent generation only:

• A. On any autosome
• B. On both the chromosome of female
• C. When they are present on X chromosome of male
• D. When they are present on X chromosome of female

Answer 1

The correct option is C

When they are present on X chromosome of male

The correct option is C:

Explanation of the correct option:

1. Males have heterozygous pair of alleles that is XY.
2. The Y chromosome does not contain any gene, whereas the X contains the gene for a recessive character. During fertilization, it can cause a recessive character in the subsequent generation.

Explanation of the incorrect options:

Option A:

The presence of recessive characters in any autosome does not guarantee the expression of the recessive characters.

Option B:

The genes need to be present on both the chromosomes to be expressed in a recessive form which is very rare.

Option D:

1. When genes are present on the X chromosome of a female, it makes the female a carrier for the gene.
2. But the recessive character will not be expressed.

Final answer: Recessive characters are expressed in the subsequent generation only when they are present on the X chromosome of males.