Frequency of recessive allele is 0.2 what is the frequency of homozygous dominant?
(a) 0.64
(b) 0.32
(c) 0.8
(d) 0.064

Options

A. 0.64
B. 0.32
C. 0.8
D. 0.064

Answer

To solve the problem of finding the frequency of the homozygous dominant genotype given the frequency of the recessive allele, we can use the Hardy-Weinberg principle. Here’s a step-by-step solution:

### Step-by-Step Solution:

1. **Understand the Given Information**:
- The frequency of the recessive allele (q) is given as 0.2.

2. **Use the Hardy-Weinberg Equation**:
- The Hardy-Weinberg principle states that \( p + q = 1 \), where:
- \( p \) = frequency of the dominant allele
- \( q \) = frequency of the recessive allele

3. **Calculate the Frequency of the Dominant Allele**:
- Since \( q = 0.2 \), we can find \( p \) as follows:
\[ p = 1 - q = 1 - 0.2 = 0.8 \]

4. **Find the Frequency of Homozygous Dominant Genotype**:
- The frequency of the homozygous dominant genotype (represented as \( p^2 \)) can be calculated by squaring the frequency of the dominant allele:
\[ p^2 = (0.8)^2 = 0.64 \]

5. **Conclusion**:
- The frequency of the homozygous dominant genotype is 0.64. Therefore, the correct answer is (a) 0.64.

### Summary of the Solution:
- The frequency of the recessive allele (q) is 0.2.
- The frequency of the dominant allele (p) is calculated as 0.8.
- The frequency of the homozygous dominant genotype (p²) is calculated as 0.64.