Question

What is the estimated size of Human genome?

• A. 3.2 billion base pairs
• B. 2.2 billion base pairs
• C. 4.1 billion base pairs
• D. 5.1 billion base pairs

Hint:

The haploid human genome size is approximately $3.2\text{ Gb}$ ($3.2$ billion base pairs).
Of this massive sequence, only about $1.5\%$ actually codes for functional proteins, while the remaining portion consists of non-coding RNAs, regulatory sequences, introns, and repetitive DNA.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
The genome size refers to the total amount of DNA contained in a single haploid set of chromosomes of an organism.
It is typically expressed in base pairs (bp) or picograms (pg) of DNA.
Determining the size of the human genome was a major milestone achieved by the Human Genome Project (HGP).

Step 2: Detailed Explanation:
The Human Genome Project was an international collaborative research effort coordinated to sequence the entire human genome.
In 2003, the project completed and published the high-quality sequence of the haploid human genome.
The haploid human genome (found in sperm or egg cells) consists of 23 chromosomes (22 autosomes and 1 sex chromosome).
This haploid genome contains approximately $3.2 \times 10^9$ base pairs, which is commonly written as 3.2 billion base pairs (or $3.2\text{ Gb}$).
Diploid somatic human cells contain two sets of these chromosomes, totaling 46 chromosomes and approximately 6.4 billion base pairs of DNA.

Step 3: Final Answer:
The estimated size of the haploid human genome is 3.2 billion base pairs.
This corresponds to Option (A).