The Composition of a Genome

The genome of almost all living organisms is composed of a chemical substance known as DNA. The Genome consists of genes that determine the traits of the living organism. The Genome includes chromosomes, which in turn contain genes that are composed of DNA. Every living entity has a unique genome. For instance, the genomes of humans, animals, and birds are all different, and even within humans, no two individuals share the same genome. Interestingly, the genomic difference between two humans is less than the genomic difference between a human and a chimpanzee.

The Human Genome: An Overview

The human genome consists of 23 pairs of chromosomes and a total of 3 billion DNA base pairs. There are 24 different types of human chromosomes, 22 of which are autosomal chromosomes, and the other two are the sex-determining X and Y chromosomes. The number of protein-coding genes in humans is estimated to be between 20,000 and 25,000. As genome sequencing techniques have improved over time, the estimated number of genes in the human body has been continuously revised from initial predictions of over 1,00,000.

Decoding DNA

DNA, or Deoxyribonucleic acid, is a molecule that carries the biological instructions that make each species unique. This DNA is passed from parent organisms to their offspring during reproduction.

Recent Developments in Genome Research

1. Recent research by the Council for Scientific and Industrial Research (CSIR)-Institute of Genomics and Integrative Biology, Delhi, and CSIR-Centre for Cellular and Molecular Biology, Hyderabad, found that 32% of genetic variations in Indian genome sequences are unique compared to global genomes. The results of this extensive computational analysis were published in the journal Nucleic Acid Research.
2. A new study conducted by the Human Heredity and Health in Africa (H3Africa) consortium, which aims to increase African representation in genetics research, uncovered 3 million new genetic variants in one of the most extensive studies of African genomes to date. The research team performed whole-genome sequencing analyses on 426 individuals representing 50 ethnolinguistic groups, including previously unsampled populations.

Additional Resources

The above information will be beneficial for candidates preparing for UPSC 2022 .