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 determine the proportion of alleles A and a in the gametes of a population containing equal numbers of individuals with genotypes AA and Aa, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Genotypes in the Population**:
- The population consists of individuals with genotypes AA and Aa.
- Let's assume there are 100 individuals in total for simplicity. Since there are equal numbers of AA and Aa, we can say there are 50 individuals with genotype AA and 50 individuals with genotype Aa.

2. **Determine the Gametes Produced by Each Genotype**:
- Individuals with genotype AA can only produce gametes with allele A. Therefore, each AA individual will contribute only A alleles.
- Individuals with genotype Aa can produce two types of gametes: A and a. Each Aa individual will contribute one A and one a allele.

3. **Calculate the Total Number of Gametes**:
- From the 50 AA individuals:
- Total A alleles = 50 individuals × 1 A allele = 50 A alleles.
- From the 50 Aa individuals:
- Total A alleles = 50 individuals × 1 A allele = 50 A alleles.
- Total a alleles = 50 individuals × 1 a allele = 50 a alleles.

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

5. **Determine the Proportion of Alleles**:
- The total number of alleles in the gametes = Total A alleles + Total a alleles = 100 + 50 = 150.
- Proportion of allele A = Total A alleles / Total alleles = 100 / 150 = 2/3.
- Proportion of allele a = Total a alleles / Total alleles = 50 / 150 = 1/3.

6. **Express the Proportions in Ratio Form**:
- The ratio of alleles A to a is 2:1.

### Final Answer:
The proportion of alleles A and a in their gametes will be 2:1.