If the DNA of a zygote has `20%` Adenine, Thymine in the gametic DNA is

Options

A. `40%`
B. `20%`
C. `30%`
D. `15%`

Answer

To solve the problem, we need to determine the percentage of thymine in the gametic DNA based on the given percentage of adenine in the zygote's DNA.

### Step-by-Step Solution:

1. **Understanding the Problem**: We are given that the DNA of a zygote has 20% adenine (A). We need to find out the percentage of thymine (T) in the gametic DNA.

2. **Applying Chargaff's Rule**: According to Chargaff's rule, in a double-stranded DNA molecule:
- The amount of adenine (A) is equal to the amount of thymine (T).
- The amount of cytosine (C) is equal to the amount of guanine (G).

3. **Identifying the Relationship**: Since the zygote's DNA has 20% adenine, by Chargaff's rule, this means:
- Percentage of thymine (T) = Percentage of adenine (A) = 20%.

4. **Conclusion**: Therefore, the percentage of thymine in the gametic DNA is also 20%.

### Final Answer:
The percentage of thymine in the gametic DNA is **20%**.

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