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The genetic information in an organism is called its genome. The Human Genome Project, or HGP for short, was started at the end of the last century. It was very ambitious and had several aims, including:

• working out the order or sequence of all the three billion base pairs in the human genome
• identifying all the genes
• developing faster methods for sequencing DNA

The sequencing project finished in 2001, and work continues to identify all the genes in the human genome. It is hoped that information from the Human Genome Project will allow scientists to develop new ways of treating or diagnosing illnesses, especially genetic disorders and cancer.

Genetic disorders

A person with cystic fibrosis has inherited two faulty alleles for a certain gene on one of their chromosomes, chromosome 7. It is hoped that one day it may be possible to repair the faulty alleles using gene therapy, for example by putting the normal allele into the cells of the lungs. This would greatly improve the lives of people with cystic fibrosis, who often need lung transplants as their illness progresses.

Breast cancer

Some people are at particular risk of developing certain types of breast cancer, because their family members carry faulty alleles. These alleles have been identified, and it is now possible to test people to see if they have an increased risk of developing breast cancer. This allows them to make decisions about whether to have surgery to remove breast tissue before any cancer develops in their breasts.