Which chromosome in the human genome has the highest number of genes?

Q: What is NEET?

NEET is a competitive examination conducted in India. This question is from the 2025 NEET Biology paper.

Q: How can I prepare for NEET Biology?

To prepare for NEET Biology, practice previous year questions (PYQs), understand concepts thoroughly, and solve mock tests regularly. This 2025 question covers Principles of Inheritance and Variation topic.

Q: What is the difficulty level of this question?

This NEET 2025 Biology question has a easy difficulty level.

Q: Where can I find more NEET previous year questions?

You can find more NEET previous year questions on AspirantMitraa. Browse by subject, topic, year, and difficulty level to practice effectively.

Question

Which chromosome in the human genome has the highest number of genes?

Accepted Answer

Correct Answer: D — Chromosome 1Step-by-step Solution:The Human Genome Project (HGP), completed in 2003 (draft 2001), sequenced the entire human genome. According to its findings: Chromosome 1 is the largest human autosome (both in physical size — ~249 million base pairs — and in gene content). It contains approximately 2,000–3,000 protein-coding genes (estimates vary by annotation method — approximately 2,058 protein-coding genes in recent Ensembl annotations). This is the highest number of genes on any single human chromosome, reflecting its large physical size.Comparison with other chromosomes:Chromosome X: ~155 million bp; ~800–1,100 protein-coding genes. Although it is larger physically than many autosomes, it underwent evolution under sex-chromosome selective pressures.Chromosome Y: ~57 million bp; only ~70–200 protein-coding genes (highly gene-poor due to evolutionary degeneration of the Y chromosome from an ancestral autosome).Chromosome 10: ~133 million bp; approximately 700–800 protein-coding genes — far fewer than chromosome 1.Extended Explanation:Key findings of the Human Genome Project: (1) The human genome contains ~3.2 billion base pairs (3.2 Gb) of DNA; (2) ~20,000–25,000 protein-coding genes (much fewer than previously estimated); (3) Only ~1.5% of the genome codes for proteins; (4) ~50% consists of repetitive sequences (transposons, SINEs, LINEs); (5) Chromosome 1 has most genes; Chromosome Y has fewest; (6) Average gene density varies widely — gene-rich chromosomes include 17, 19, 22; gene-poor chromosomes include 4, 8, 13, 18; (7) The human genome is 99.9% identical between individuals; the 0.1% variation accounts for all human diversity. HGP was an international collaboration (USA, UK, France, Germany, Japan, China) started in 1990. Technologies used: Sanger sequencing (first), later whole-genome shotgun sequencing (Celera Genomics, Craig Venter). Applications: personalized medicine, pharmacogenomics, understanding genetic diseases, forensics, evolutionary biology.Key Concepts: Human Genome Project, chromosome 1 (largest, most genes), chromosome Y (fewest genes), genome statistics, gene density, sequencing technologies.

Which chromosome in the human genome has the highest number of genes?

Master NEET with Our Test Series

More Questions from Principles of Inheritance and Variation

Frequently Asked Questions

Which chromosome in the human genome has the highest number of genes?

Master NEET with Our Test Series

More Questions from Principles of Inheritance and Variation

Frequently Asked Questions