Mapping the human genome

In 1990, the USA initiated an international effort, the Human Genome Project, to determine the complete sequence of the three billion pairs that constitute the 23 chromosomes of human cells and to identify the 100,000 or so genes that define the human species. The year 2005 was established as the target date for completion. A map produced in 1996 by French and American scientists pinpoints 5,264 markers to help scientists work out the human genome. The development of the genome map is expected to provide invaluable help to scientists working on the more than 3,000 hereditary diseases known to science.