Question

Which of the following statements is incorrect?
Statements:
(i) Colour blindness is an example of multiple allelism
(ii) Multiple alleles cannot be observed in the genotype of a diploid individual
(iii) Multiple alleles can be observed in the genotype of a population
(iv) Multiple alleles are represented by the inheritance of blood groups

• A. Only (i) is incorrect
• B. Only (ii) is incorrect
• C. Only (i) and (ii) are incorrect
• D. Only (iii) is incorrect

Hint:

Multiple alleles exist in a population, but only two appear in a diploid individual.

Answer 1

The Correct Option is A

Step 1: Understanding multiple allelism.
Multiple allelism refers to the presence of more than two alternative alleles of a gene in a population. However, a single diploid individual can carry only two alleles at a time.

Step 2: Evaluating statement (i).
Colour blindness is a sex-linked recessive disorder, not an example of multiple allelism. It is controlled by a single gene on the X-chromosome. Therefore, statement (i) is incorrect.

Step 3: Evaluating statement (ii).
A diploid organism carries only two alleles per gene locus, even if multiple alleles exist in the population. Hence statement (ii) is correct.

Step 4: Evaluating statement (iii).
Multiple alleles are studied at the population level, not individual level. Therefore statement (iii) is correct.

Step 5: Evaluating statement (iv).
ABO blood group system is a classic example of multiple allelism (IA, IB, i). Hence statement (iv) is correct.

Step 6: Final conclusion.
Only statement (i) is incorrect.