1. What is Aa Frequency?

The Aa frequency represents the proportion of heterozygous individuals in a population under Hardy-Weinberg equilibrium. It's one of the three possible genotype frequencies (AA, Aa, aa) for a gene with two alleles.

2. How Does the Calculator Work?

The calculator uses the Hardy-Weinberg equation:

Where:

• \( p \) — Frequency of allele A (dimensionless)
• \( q \) — Frequency of allele a (dimensionless)
• \( 2pq \) — Frequency of heterozygous genotype Aa

Explanation: The equation assumes random mating, no selection, no mutation, no migration, and large population size.

3. Importance of Genotype Frequency

Details: Calculating genotype frequencies is fundamental in population genetics, helping predict disease risks, understand evolutionary processes, and study genetic diversity.

4. Using the Calculator

Tips: Enter allele frequencies p and q (must be between 0 and 1, and p + q ≤ 1). The calculator will compute the Aa genotype frequency.

5. Frequently Asked Questions (FAQ)

Q1: What is Hardy-Weinberg equilibrium?
A: It's a principle stating that allele and genotype frequencies remain constant from generation to generation in the absence of evolutionary influences.

Q2: Why is Aa frequency 2pq?
A: Because heterozygotes can form in two ways - A from father and a from mother, or a from father and A from mother.

Q3: What are the assumptions of Hardy-Weinberg?
A: No mutation, random mating, no natural selection, extremely large population size, and no gene flow.

Q4: How is this useful in real populations?
A: Deviations from expected frequencies can indicate evolutionary forces at work (selection, migration, etc.) or non-random mating.

Q5: Can this be used for multiple alleles?
A: The basic equation is for two alleles, but extensions exist for multiple alleles with more complex calculations.