Final human chromosome mapped

After 10 years of work, 150 British and American scientists have completed a genetic map of human chromosome one, the largest of the 23 bundles of genetic material in the human body. Chromosome one makes up about eight per cent of the total human genome, and contains about twice as many genes as an average-sized chromosome - if it were typed out, say the scientists, the genetic information on chromosome one would cover 60,000 pages. The scientists have published their findings in the journal Nature.

An international consortium unveiled the final version of the entire human genome on 14 April 2003. They found that it is made of 2.9 billion base-pairs (chemical 'letters') of DNA, and contains an estimated 25-30,000 different genes. Researchers have since been looking at each of its 24 different chromosomes in detail, to identify the 'coding' stretches of DNA that make up these genes. They have also been filling gaps - stretches of DNA sequence that could not easily be determined - and double-checking for any errors.

Chromosome 1 has been found to contain 3,141 genes and genetic mutations of these genes have been found to have links to over 350 illnesses, including cancer, Alzheimer's and Parkinson's disease - making it the most gene dense chromosome in the human body. Also, according to the press release, the sequence of Chromosome one has enabled the scientists to identify more than 1000 new genes and is 'expected to help researchers find novel diagnostics and treatments for many diseases'.

Dr Simon Gregory, who headed the sequencing project at the Wellcome Trust Sanger Institute in Cambridge, UK, said that 'this achievement effectively closes the book on an important volume of the Human Genome Project, which was started in 1990 to identify the genes and DNA sequences that provide a 'blueprint' for human beings'. Dr Mark Walport, Director of the Wellcome Trust, said that 'the completion of the project, with the publication of the Chromosome 1 sequence, is a monumental achievement that will benefit the research community for years to come and is a credit to all involved'.