As many as half the company's gene sequences for the fruit fly may contain mistakes, says Samuel Karlin, a mathematician at Stanford University in California. His work suggests there might be many errors in other genomes that have been sequenced using similar techniques, he says. But others have defended the results. An update next yearshould improve its accuracy to 75 per cent, he says. Rubin was one of the coauthors when the head of Celera, Craig Venter, published the full sequence of the fly genome in Science in March 2000.
Computers then assemble the full sequence by looking for overlapping fragments.
But when Karlin began to use Celera's fly genome, he spotted lots of errors. So he did a fuller analysis with his colleagues. They hunted through Celera's genome for 1049 fly genes whose sequence and function had already been worked out and carefully checked in experiments. Although 26 per cent of the genes were exact matches, and a further 29 per cent accurate to within 1 per cent, the remaining 45 per cent contained a range of moderate to serious errors - or were missing altogether. Karlin claims there could be worse errors in both the public and private versions of the human genome.