Question

An example of quantitative inheritance is

• A. Colour of skin
• B. Colour blindness
• C. Klinefelter's syndrome
• D. Alkaptonuria

Answer 1

The correct option is A

Colour of skin

The correct option is A.

The explanation for the correct option:

1. Quantitative inheritance is caused by one or more genes.
2. Hence it is referred to as polygenic inheritance.
3. The colour of skin is controlled by genes A, B, and C.
4. The phenotypic effect of all these genes together is responsible for the formation of the phenotypic effect of skin colour.
5. Hence it is a quantitative inheritance.

The explanation for the incorrect options:

Option B:

1. Colour blindness is caused due to X-linked inheritance.
2. In this disease, only males show the phenotypic effect of colour blindness and females are the only carriers.

Option C:

1. Because of abnormality in the sex chromosome, Klinefelter's syndrome takes place.
2. The number of chromosomes gets increased to 47 in this disease.

Option D:

1. In Alkaptonuria, reduction in oxidase enzyme leads to abnormal metabolism.
2. Hence, Alkaptonuria is a Metabolic disease.

Final answer:

An example of quantitative inheritance is colour of skin.