Question

Multiple alleles control inheritance of

• A. phenylketonuria
• B. colour blindness
• C. sickle cell anaemia
• D. blood groups.

Answer 1

The Correct Option is D

The question asks about inheritance controlled by multiple alleles. Let's explore the concept of multiple alleles and determine which option is correct:

Concept of Multiple Alleles: Multiple alleles refer to the existence of more than two allelic forms of a gene within a population. While an individual carries only two alleles for a gene (one from each parent), the population may contain several distinct alleles for that gene.

1. Phenylketonuria: Phenylketonuria is a genetic disorder caused by a mutation in the PAH gene. It follows a simple recessive inheritance pattern and is not controlled by multiple alleles.
2. Colour Blindness: Colour blindness is typically linked to the X chromosome. It is an example of X-linked recessive inheritance and not an example of multiple alleles.
3. Sickle Cell Anaemia: Sickle cell anaemia is another genetic disorder resulting from a specific point mutation in the HBB gene, following a Mendelian pattern of inheritance.
4. Blood Groups: The ABO blood group system is a classic example of multiple alleles. The blood type of an individual is determined by three alleles: I^A, I^B, and i. There are four blood types (A, B, AB, and O) resulting from different combinations of these three alleles.

Conclusion: The correct answer is blood groups as it is the only option where multiple alleles control inheritance.