We humans may have thousands more genes than the genome sequencers have led us to believe
"ONE giant leap for humility". "We're nothing special". "Scientists find only half as many genes as expected". These are some of the headlines that appeared after papers on the draft genome were published in February. Both the public and private projects estimated we had just 30,000 to 40,000 genes, far fewer than most previous figures suggested-and barely more than worms.
But the low estimates have ignited a firestorm of controversy. William Haseltine, head of biotech company Human Genome Sciences (HGS) in Rockville, Maryland, has been the most outspoken critic, attacking both the quality of the draft sequences and the gene-finding efforts of those who compiled them. "They're reading smudged text through foggy glasses," he recently snarled. Haseltine claims to have found more than 90,000 genes, while companies such as Affymetrix sell gene chips based on more than 60,000 genes and DoubleTwist puts the number above 65,000.
But Craig Venter, head of Celera Genomics, the private rival to the public genome consortium, is standing by the lower estimate. He calls it a "truth serum" for his competitors. So are these companies wasting hundreds of millions of dollars on a wild goose chase? Or could the public consortium and Celera end up delaying the development of medical tests and treatments by denying the existence of large numbers of genes?
The accuracy of the draft genome is not the issue. The controversy is about how you find the fragmented parts of the genome that actually code for proteins. There are 26,000 genes that researchers more or less agree on. In the papers in Nature and Science (New Scientist, 17 February, p 4), the public consortium and Celera estimated that there are about another 10,000, based on computer programs that search raw sequences for stretches that resemble known genes.