Select the correct features of Human Genome Project.
(A) The human genome contains 3164.7 million bp.
(B) The functions are unknown for over 70 per cent of the discovered genes.
(C) Chromosome 1 has most genes (2968), and the Y has the fewest (231).
(D) More than 20 per cent of the genome codes for proteins.
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → (A) and (C) only
The Human Genome Project (HGP) was a mission to find the sequence of all the base pairs in the human genome. Its main findings are given in NCERT as salient features.
(A) The human genome contains 3164.7 million bp. — Correct. This is the size of the human genome.
(B) The functions are unknown for over 70 per cent of the discovered genes. — Incorrect. The functions are unknown for over 50 per cent of the discovered genes.
(C) Chromosome 1 has most genes (2968), and the Y has the fewest (231). — Correct. These are the numbers given for the largest and the smallest gene counts.
(D) More than 20 per cent of the genome codes for proteins. — Incorrect. Less than 2 per cent of the genome codes for proteins. Most of it is repeated sequences, which have no direct coding function.
NCERT Extract:
Salient Features of Human Genome – “… (i) The human genome contains 3164.7 million bp. (ii) The average gene consists of 3000 bases, but sizes vary greatly, with the largest known human gene being dystrophin at 2.4 million bases. (iii) The total number of genes is estimated at 30,000– much lower than previous estimates of 80,000 to 1,40,000 genes. Almost all (99.9 per cent) nucleotide bases are exactly the same in all humans. (iv) The functions are unknown for over 50 per cent of the discovered genes. (v) Less than 2 per cent of the genome codes for proteins. (vi) Repeated sequences make up very large portion of the human genome. (vii) Repetitive sequences are stretches of DNA sequences that are repeated many times, sometimes hundred to thousand times. They are thought to have no direct coding functions, but they shed light on chromosome structure, dynamics and evolution. (viii) Chromosome 1 has most genes (2968), and the Y has the fewest (231).”