How many different types of gametes will be formed by a pea plant with genotype TtYy upon self fertilization?

Options

A. 16
B. 8
C. 6
D. 4

Answer

To determine how many different types of gametes will be formed by a pea plant with the genotype TtYy upon self-fertilization, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Genotype**: The given genotype is TtYy. This means the plant has two traits:
- T (Tall) with alleles T (dominant) and t (recessive)
- Y (Yellow) with alleles Y (dominant) and y (recessive)

2. **Determine the Number of Heterozygous Alleles**:
- In the genotype TtYy, there are two heterozygous pairs: Tt and Yy.
- Each pair contributes to the formation of different gametes.

3. **Use the Gamete Formation Formula**:
- The formula to calculate the number of different types of gametes is \(2^n\), where \(n\) is the number of heterozygous gene pairs.
- Here, \(n = 2\) (since we have Tt and Yy).

4. **Calculate the Number of Gametes**:
- Plugging into the formula:
\[ 2^n = 2^2 = 4 \]
- Therefore, the number of different types of gametes formed is 4.

5. **List the Possible Gametes**:
- The possible gametes from TtYy are:
- TY (T from Tt and Y from Yy)
- Ty (T from Tt and y from Yy)
- tY (t from Tt and Y from Yy)
- ty (t from Tt and y from Yy)

### Final Answer:
The pea plant with genotype TtYy will form **4 different types of gametes** upon self-fertilization.

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