An organism has two unlinked genes P and Q. Its genotype is PpQq . How many different types of gametes will be formed?

Options

A. Two
B. Six
C. Four
D. Eight

Answer

To determine how many different types of gametes will be formed from the genotype PpQq, we can follow these steps:

### Step 1: Identify the Genotype
The given genotype is PpQq. This indicates that there are two genes (P and Q), each with two alleles. The alleles for gene P are P (dominant) and p (recessive), and for gene Q, they are Q (dominant) and q (recessive).

### Step 2: Determine the Number of Heterozygous Genes
In the genotype PpQq, both genes are heterozygous:
- Gene P has alleles P and p (heterozygous)
- Gene Q has alleles Q and q (heterozygous)

### Step 3: Use the Formula for Gamete Formation
The number of different types of gametes can be calculated using the formula:
\[ \text{Number of gametes} = 2^n \]
where \( n \) is the number of heterozygous gene pairs.

### Step 4: Calculate the Value of n
In this case, we have:
- 1 heterozygous pair for gene P (Pp)
- 1 heterozygous pair for gene Q (Qq)

Thus, \( n = 2 \).

### Step 5: Calculate the Number of Gametes
Now, substituting \( n \) into the formula:
\[ \text{Number of gametes} = 2^2 = 4 \]

### Conclusion
Therefore, the total number of different types of gametes that can be formed from the genotype PpQq is **4**.

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