It is already developing drugs using its antisense technology, a way of turning off particular genes.

But there is no general evidence that distinctive cultural traits are associated with particular genes.

Should, for example, workers with particular genes be kept out of jobs that entail exposure to certain chemicals?

Above right, a particular gene is traced to visualize how different species are related.

Every protein is coded for by a particular gene in the cell's nucleus.

The two studies provide strong evidence that the disease is caused by a defect, or defects, in one particular gene, the scientists said.

The method can be used both to disrupt particular genes and to add new genetic material at a specific site.

They can also be used to test which variations of particular genes a person has.

For example, a researcher investigating a certain form of cancer may have narrowed down his/her search to a particular gene.

The value of a particular gene might be, say 4, or -7.