Estimated number of genes in human being is

Options

A. 3000
B. 80000
C. 20500
D. `3xx10^9`

Answer

To solve the question regarding the estimated number of genes in human beings, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Human Genome Size**:
The human genome consists of approximately 3.1647 billion base pairs (bp).

2. **Estimate Average Gene Size**:
The average size of a gene is approximately 3000 base pairs.

3. **Calculate the Estimated Number of Genes**:
To estimate the number of genes, we can divide the total number of base pairs by the average size of a gene:
\[ \text{Estimated number of genes} = \frac{\text{Total base pairs}}{\text{Average gene size}} = \frac{3,164,700,000 \text{ bp}}{3,000 \text{ bp/gene}}. \]

4. **Perform the Calculation**:
\[ \text{Estimated number of genes} = \frac{3,164,700,000}{3,000} \approx 1,054,900. \]

5. **Adjust for Realistic Gene Count**:
However, the estimated number of functional genes in humans is generally accepted to be between 20,000 and 25,000. This is due to the fact that not all sequences in the genome correspond to functional genes.

6. **Final Estimate**:
Therefore, the estimated number of genes in human beings is approximately 20,000 to 25,000, with a commonly cited figure of around 20,500.

### Final Answer:
The estimated number of genes in human beings is approximately **20,000 to 25,000**, with a commonly accepted figure of **20,500**.

---