The human genome wasn鈥檛 invaded by genes from bacteria, after all.
Earlier this year, it was claimed that over 100 bacterial genes had somehow jumped into the genomes of vertebrates. But Michael Stanhope and his team at GlaxoSmithKline in Pennsylvania think the claims were based on faulty analysis. They say their findings should calm fears that genes from genetically engineered foods or bacteria could easily jump to humans.
When the first analysis of the human genome appeared in February 2001 (快猫短视频, 17 February, p 4), researchers said they鈥檇 found 223 genes that were common to humans and bacteria but absent from evolutionary links between bacteria and vertebrates such as yeasts, worms and flies. They suggested that at least 113 genes had jumped straight from bacteria into vertebrates.
Advertisement
But while bacteria regularly swap genes among themselves, Stanhope was sceptical that there had been so many transfers to vertebrates. 鈥淥ne or two would be very interesting,鈥� says Stanhope. 鈥淥ne hundred and thirteen? Incredibly extraordinary.鈥�
Man infects bacteria
Stanhope鈥檚 team picked 28 of the genes and used computer tests to study their evolution and relation to other genes more closely. The team also ran tests on a database the original study had overlooked.
They found no evidence of bacterial genes suddenly crossing to humans. Instead, they found that invertebrates such as flies and worms had similar genes, showing that all animals inherited them from a common ancestor after all. But there has been traffic the other way 鈥� they found evidence that one gene has jumped from humans to bacteria.
Other researchers have also cast doubt on the original bacterial transfer study (Science, vol 292, p 190), highlighting problems with the computational methods used.
鈥淚t鈥檚 a bit symptomatic of the bioinformatics field at the moment 鈥� it鈥檚 sometimes missing the biological perspective,鈥� says Stanhope. 鈥淲e need to keep in mind that bringing order to genomic sequences is a biological issue.鈥�
More at: Nature (vol 411, p 940)