Question

If the observed heterozygosity at a locus is 0.6, which one or more of the following could produce this outcome?

• A. A neutral locus with three alleles
• B. A locus under selection with two alleles
• C. A neutral locus with two alleles
• D. A locus under selection with one allele

Hint:

Higher heterozygosity can be maintained at a locus with multiple alleles or under selection, especially if heterozygous individuals have a fitness advantage.

Answer 1

The Correct Option is A, B

Step 1: Understanding heterozygosity.
Heterozygosity refers to the proportion of individuals in a population that are heterozygous at a given locus. A value of 0.6 indicates a relatively high level of genetic diversity at the locus. 
Step 2: Analyzing the options. 
- (A) A neutral locus with three alleles: A locus with three alleles can result in higher heterozygosity, and a value of 0.6 is reasonable for such a locus. 
- (B) A locus under selection with two alleles: Selection can maintain or increase heterozygosity at a locus, especially if heterozygous individuals have a fitness advantage. A heterozygosity of 0.6 is feasible here. 
- (C) A neutral locus with two alleles: This could result in lower heterozygosity, typically around 0.5 for a two-allele system in Hardy-Weinberg equilibrium. It would be less likely to result in 0.6 heterozygosity. 
- (D) A locus under selection with one allele: A single allele would result in no heterozygosity at all, so this option is not feasible. 
Step 3: Conclusion. 
The correct answers are (A) and (B), as both can explain the observed heterozygosity of 0.6.