Cross - over value (COV) of genes M and N is 5% while COV of genes N and P is 15% . The possible sequence of three genes on chromosome is

Options

A. M-N-P
B. P-M-N
C. N-P-M
D. Both A and B

Answer

To solve the question regarding the possible sequence of three genes (M, N, and P) on a chromosome based on their crossover values, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Crossover Values**:
- The crossover value (COV) between genes M and N is given as 5%. This means that there is a 5% chance that M and N will be separated during gamete formation.
- The crossover value between genes N and P is given as 15%, indicating a 15% chance of separation.

2. **Converting Crossover Values to Map Units**:
- Crossover values can be interpreted as map units on a chromosome.
- Therefore, the distance between M and N is 5 map units, and the distance between N and P is 15 map units.

3. **Arranging the Genes**:
- We need to determine the possible arrangement of these genes on the chromosome.
- Since M and N are 5 map units apart, we can represent them as M — N.
- The distance between N and P being 15 map units suggests that P must be positioned further away from N.

4. **Possible Arrangements**:
- If we place N in the middle, we can have two possible arrangements:
- M — N — P (where M is 5 map units from N, and N is 15 map units from P).
- Alternatively, we can also consider P — M — N (where P is at one end, M is 5 map units from N, and N is 15 map units from P).

5. **Verifying Arrangements**:
- The arrangement M — N — P satisfies the distance requirements: M is 5 map units from N, and N is 15 map units from P.
- The arrangement P — M — N also satisfies the distance requirements: P is 15 map units from N, and M is 5 map units from N.

6. **Conclusion**:
- The possible sequences of the three genes on the chromosome are M — N — P and P — M — N.

### Final Answer:
The possible sequences of the three genes on the chromosome are:
- MNP
- PMN