For the MN-blood group system. The frequencies of M and N alleles are 0.7 and 0.3, respectively. The expected frequency of MN-blood group bearing organisms is likely to be

Options

A. 0.42
B. 0.49
C. 0.09
D. 0.58

Explanation

To find the expected frequency of MN blood group bearing organisms using the Hardy-Weinberg principle, we can follow these steps:

### Step-by-Step Solution:

1. **Identify Allele Frequencies**:
- The frequency of allele M (p) = 0.7
- The frequency of allele N (q) = 0.3

2. **Apply Hardy-Weinberg Principle**:
- According to the Hardy-Weinberg principle, the expected genotype frequencies in a population can be calculated using the formulas:
- \( p^2 \) = frequency of homozygous MM
- \( 2pq \) = frequency of heterozygous MN
- \( q^2 \) = frequency of homozygous NN

3. **Calculate \( p^2 \)**:
- \( p^2 = (0.7)^2 = 0.49 \)

4. **Calculate \( q^2 \)**:
- \( q^2 = (0.3)^2 = 0.09 \)

5. **Calculate \( 2pq \)**:
- \( 2pq = 2 \times (0.7) \times (0.3) = 2 \times 0.21 = 0.42 \)

6. **Summarize the Results**:
- The expected frequencies are:
- Frequency of MM = 0.49
- Frequency of NN = 0.09
- Frequency of MN = 0.42

7. **Conclusion**:
- The expected frequency of MN blood group bearing organisms is 0.42.

### Final Answer:
The expected frequency of MN blood group bearing organisms is **0.42**.