Wall showing the different nucleotides A, G, T and C in DNA

All in sequence

Why is determining an organism’s genome sequence important?

Most types of cell in an organism contain a complete copy of its genome. The organisation is quite complicated, but the simplest fact about any genome is that it is a collection of DNA sequences – long strings of the chemical ‘letters’ A, T, G and C (adenine, thymine, guanine and cytosine) in a particular order.

Learn to read an organism’s genome sequence, and compare it with that of other organisms, and it can tell you lots of different things.

The human genome sequence contains a wealth of information about human biology, in both health and disease. Our DNA is a window on evolution and recent human history – including the migration of people around the world.

The genome sequences of other species have many other uses. The genomes of organisms used in farming, from rice and wheat to pigs and cattle, are being sequenced to help to breed improved strains. But the vast majority of the many thousands of genomes already completed are from bacteria. Some are species that cause diseases in people, as well as in agriculturally important animals or plants.

Others are important for maintaining health or have potential uses in the industrial production of biologically active chemicals and enzymes.

Genomic information is used to track harmful microbes such as those that cause infection in hospitals, as well as to aid the development of new drugs. New influenza strains have their genomes read quickly to understand how the virus spreads and to speed up vaccine production.

Knowledge of genome sequences also speeds up developments in biotechnology and is finding uses in tracking biodiversity and policing trade in protected species.

Lead image:

A wall of genetic code in the Wellcome Wing of the Science Museum, showing the A, T, G and C nucleotides

Nathan Nelson/Flickr CC BY NC ND


About this resource

This resource was first published in ‘Genes, Genomes and Health’ in January 2010 and reviewed and updated in December 2014.

Genetics and genomics, Microbiology, Ecology and environment, History, Health, infection and disease, Biotechnology and engineering
Genes, Genomes and Health
Education levels:
16–19, Continuing professional development