The human genome

The genome of an organism is the whole of its hereditary information encoded in its DNA.

Genomes contain around 20,000 genes. Genes are the instructions for making the proteins that our bodies are built from. Genomes also contain many other DNA sequences that do not code for proteins

The whole human genome has been studied and this has great importance for medicine.

In order to exploit its secrets, it is vital that the human genome is fully understood.

It enables us to:

  • search for genes linked to different types of disease
  • understand inherited disorders and their treatment
  • trace human migration patterns from the past

Scientists are searching for disease associated genes. One example is the genes that can contribute to breast cancer, which are known as BRCA1 and BRCA2. Mutations in these genes account for approximately 10 per cent of all inherited breast cancer cases detected.

Scientists detected BRCA1 and BRCA2 genes by studying individuals in families known to have inherited breast cancer. They were able to create a pedigree analysis, which is similar to a family tree diagram, that showed the close relationship of those affected and unaffected within the family.

The pedigree analysis illustrates the inheritance pattern of the disease. This enables scientists to test DNA of the affected and unaffected individuals to identify differences. It is now possible to detect the presence of the genes by having a simple blood test.