A population contains equal number of individuals with the genotype AA and Aa. Proportion of alleles A & a in their gametes will be :-

Options

A. `3:1`
B. `1:1`
C. `1:2`
D. Can't be determined

Answer

To solve the problem, we need to determine the proportion of alleles A and a in the gametes produced by a population with equal numbers of individuals with genotypes AA and Aa.

### Step-by-Step Solution:

1. **Identify the Genotypes in the Population**:
- The population has individuals with genotypes AA and Aa in equal numbers. Let's assume there are 100 individuals in total, with 50 AA and 50 Aa.

2. **Determine the Gametes Produced by Each Genotype**:
- **AA Genotype**: Individuals with genotype AA can only produce gametes with allele A. Therefore, each AA individual produces 2 A gametes.
- **Aa Genotype**: Individuals with genotype Aa can produce gametes with either allele A or allele a. Therefore, each Aa individual produces 1 A gamete and 1 a gamete.

3. **Calculate Total Gametes from Each Genotype**:
- From 50 AA individuals:
- Total A gametes = 50 individuals × 2 A gametes = 100 A gametes.
- From 50 Aa individuals:
- Total A gametes = 50 individuals × 1 A gamete = 50 A gametes.
- Total a gametes = 50 individuals × 1 a gamete = 50 a gametes.

4. **Sum Up the Total Gametes**:
- Total A gametes = 100 (from AA) + 50 (from Aa) = 150 A gametes.
- Total a gametes = 50 (from Aa) = 50 a gametes.

5. **Calculate the Proportion of Alleles**:
- The total number of gametes produced = Total A gametes + Total a gametes = 150 + 50 = 200.
- Proportion of allele A = Total A gametes / Total gametes = 150 / 200 = 3/4.
- Proportion of allele a = Total a gametes / Total gametes = 50 / 200 = 1/4.

6. **Express the Proportion in Ratio Form**:
- The ratio of allele A to allele a is 150:50, which simplifies to 3:1.

### Final Answer:
The proportion of alleles A and a in their gametes will be **3:1**.

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