Human Genome Project
மனித மரபணு திட்டம்
The Human Genome Project is not just history; it is the blueprint of your existence. 3 billion base pairs define your phenotype, yet 99.9% of that sequence is identical in every human. If you cannot distinguish between a gene and a non-coding sequence, you are not ready for the exam.
The idea
HGP was a 13-year mega project launched in 1990 to sequence the entire human genome. It aimed to identify all 20,000-25,000 genes using automated DNA sequencers and bioinformatics. Scientists utilized BAC (Bacterial Artificial Chromosome) and YAC (Yeast Artificial Chromosome) as vectors for cloning. The project successfully mapped the 3 billion base pairs, providing a foundational database for modern genetics.
Why it matters
It exists to provide a complete map of human genetic information, enabling advancements in medicine, diagnostics, and understanding human evolution.
NEET lens
NEET focuses on the methodology: remember BAC and YAC as cloning vectors. Do not confuse the number of genes (20,000-25,000) with the number of base pairs (3 billion). Frequently asked questions target the project duration and the role of bioinformatics.
Clinical significance
Understanding the genome allows for the identification of single nucleotide polymorphisms (SNPs) linked to hereditary diseases. When this genetic information is decoded, clinicians can predict susceptibility to disorders like Cystic Fibrosis or Huntington’s disease. Precision medicine relies entirely on this genomic data to tailor treatments.
Introduction
The Human Genome Project (HGP), launched in 1990 and completed in 2003, aimed to determine the complete DNA sequence of the human genome. It was a 13-year mega project.
Core concept
Goals: identify all the genes (about 20,000-25,000) in human DNA; determine the sequences of the 3 billion chemical base pairs; store the information in databases; improve tools for data analysis; transfer related technologies to other sectors; address ethical, legal and social issues (ELSI). Methods: Expressed Sequence Tags (ESTs) — identifying all genes that are expressed as RNA; Sequence Annotation — sequencing the whole set of genome, coding and non-coding, and later assigning functions (the 'blind' approach). DNA was broken into fragments, cloned in host vectors such as BAC (bacterial artificial chromosomes) and YAC (yeast artificial chromosomes), and sequenced with automated sequencers (based on Frederick Sanger's method). Salient features: the human genome contains 3164.7 million bp; the total number of genes is estimated at about 30,000; average gene has 3000 bases (largest, dystrophin, 2.4 million bases); less than 2% of the genome codes for proteins; chromosome 1 has most genes (2968), Y has the fewest (231); about 1.4 million single-base DNA differences (SNPs) identified.
Go deeper
Repeated sequences make up a large portion of the human genome. Bioinformatics — the use of computers to store and analyse biological data — grew alongside HGP.
From Class 10
Imagine writing down every letter of a 3-billion-letter book that describes how to build a human — that is what HGP did.