Question

Which one of the following statements is the correct fact about human genome project?

• A. The average gene consists of 30000 bases.
• B. The functions are unknown for less than 20 percent of the discovered genes.
• C. Less than 2 percent of the genome codes for proteins.
• D. Chromosome Y has the most genes (2968), and 1 has the fewest (231).

Hint:

Salient Features of HGP:
$\bullet$ Total bases $\approx 3.164$ billion bp.
$\bullet$ Average gene size = 3,000 bases.
$\bullet$ Coding region $<$ 2% of total genome.
$\bullet$ Chromosome 1 has 2968 genes (maximum).
$\bullet$ Chromosome Y has 231 genes (minimum).

Answer 1

The Correct Option is C

Concept:
The Human Genome Project (HGP) provided quantitative insights into the structure, organization, size, coding capacity, and distribution of genes in the human genome.

Step 1: Evaluation of Salient Features of Human Genome:
- Option (A): The human genome contains approximately $3.1647 \times 10^9$ base pairs. The average gene consists of 3,000 bases (not 30,000 bases), although sizes vary greatly (with dystrophin being the largest at 2.4 million bases). Thus, (A) is incorrect.
- Option (B): The functions are unknown for over 50 percent (more than half) of the discovered genes, not less than 20 percent. Thus, (B) is incorrect.
- Option (C): Less than 2 percent of the entire human genome sequence codes for functional proteins; the remaining over 98 percent consists of non-coding, repetitive sequences. Thus, (C) is correct.
- Option (D): Chromosome 1 contains the highest number of genes (2,968 genes), whereas the Y chromosome has the fewest genes (231 genes). The statement has these values reversed. Thus, (D) is incorrect.

Step 2: Final Answer:
The only true statement regarding the human genome is that less than 2 percent of the genome codes for proteins.