Scientists unravel chromosome that causes Down's syndrome
By Victoria Griffith in Boston
Published: May 8 2000 18:26GMT | Last Updated: May 8 2000 23:01GMT
A group of German and Japanese scientists has deciphered the human chromosome responsible for Down's syndrome, in the latest breakthrough in an intensifying international race to understand human genetic architecture.
Separately, the Human Genome Project, a publicly funded international research programme, announced it was within six weeks of completing a working draft of the human genome, the so-called "book of life" that lists 90 per cent of the DNA contained in human genes.
The Human Genome Project is in fierce competition with Celera Genomics, a quoted US company, to become the first to sequence the human genome. Unlike the HGP, Celera, which claims to be in the lead, plans to charge for access to the data.
The German and Japanese scientists, working with the HGP, said on Monday they had unravelled chromosome 21, only the second of 23 chromosome pairs which make up the human genome.
Chromosome 22 was sequenced last December by the Sanger Institute, another international research centre, a discovery that contributed to a rally in US biotechnology stocks early this year.
Chromosome 21 is of particular interest because of its links to Alzheimer's disease and certain forms of cancer, as well as its role in Down's syndrome. The findings were published online by Nature, the science magazine, on Monday.
Because of a surprising paucity of genes on chromosome 21, researchers are predicting that the number of genes in the human genome is only 40,000, one-third to one-half the number previously estimated. If true, that would mean that all human genes have already been identified - although the complete DNA sequencing of the genes is still unknown.
German scientists will use the chromosome 21 accomplishment to call for an increase in federal funding of genomics projects, said Jorg Wadzack of the German Human Genome Project.
Once considered a purely scientific undertaking, the race to unravel the human "book of life" is taking on greater commercial significance.
"The next wave of genomic research is along the lines of the chromosome 21 research - going deeper rather than broader," says David Molowa, biotechnology analyst with Bear Stearns. The Germans, Japanese and British are interested in spinning off their research to form the basis of commercial enterprises, he added.
The high commercial stakes of genomics research were highlighted on Monday as DoubleTwist, a US genomics group, and Sun Microsystems, the computer company, announced they had finished the first annotation of the human genome, information the groups intend to sell.
While "sequencing" merely provides the most basic information about the human DNA, "annotation" actually locates the genes.
"With sequencing, we get all the letters of a text, with no punctuation, in a language we can't understand," says Eric Lander, director of the Whitehead Centre for Genomic Research in Cambridge, Massachusetts.
"Annotation gives us words, but we still can't read the sentence." Until scientists understand more about gene function and disease links, genomic data is of limited use in drug development.
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