What is a gene?

The DNA double helix stores information in the form of a genetic code. Sections of DNA that contain complete messages are known as genes. They can be thought of as 'words' along the DNA 'sentences'.

Genes are messages that provide the information for all cellular functions. They carry information that is passed on to future generations.

An organism's genes determine:

  • the characteristics that are used to classify it into the plant or animal kingdom and into a specific family and species
  • how it uses food
  • how well it fights infection
  • at times, how it behaves.

Each human cell (except red blood cells) contains between 25,000 and 42,000 genes. Genes control the production of proteins that make up most of your body.

The word ‘gene’ was not invented until 1909.

How genes work

To do their job, genes need more than just the code for a product. Each gene also has regulatory (manager) sections, which are important for its control.

The first regulator is a promoter that controls such things as switching the gene off or on. This effectively controls which cells the gene will work in, when the gene will work, for how long and how hard.

The second regulator comes at the end of the gene. This is the stop regulator that controls when the gene will stop working and how long the product of the gene will last. Between these two regulator sections of the gene is the code for the protein product.

Each organism has its own regulators. So, an entire gene from one organism will not automatically work if it is placed in a different organism.

To make a gene work in a different organism, the regulator sections specific to that organism usually need to be inserted along with the gene.