If interference is complete or cent percent then the frequency of observed crossover will be

Options

A. Equal to expected frequency
B. Greater than expected frequency
C. Lesser than expected frequency
D. zero

Answer

To solve the question, "If interference is complete or cent percent then the frequency of observed crossover will be," we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Concept of Interference**:
- Interference in genetics refers to the phenomenon where one crossover event affects the likelihood of another crossover occurring nearby.

2. **Define Complete Interference**:
- Complete interference means that if one crossover occurs, it completely prevents any other crossover from occurring in adjacent regions. This is represented mathematically as interference (I) being equal to 1.

3. **Mathematical Representation**:
- The relationship can be expressed as:
\[ I = 1 - \text{(Observed Double Crossover Frequency)} \]
- If interference (I) is 1 (100%), then:
\[ 1 = 1 - \text{(Observed Double Crossover Frequency)} \]
- Rearranging this gives:
\[ \text{Observed Double Crossover Frequency} = 0 \]

4. **Conclusion**:
- Since the observed double crossover frequency is 0, it implies that the frequency of observed crossover events is also 0 when interference is complete. Thus, the answer to the question is:
\[ \text{Frequency of observed crossover} = 0 \]

### Final Answer:
The frequency of observed crossover will be **0** if interference is complete or cent percent.

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