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No evidence for the ‘horizontal’ transfer of genes from bacteria to humans
Edward R. Winstead

A new study effectively dismisses the notion that humans have acquired genes directly from bacteria during evolution. The study is the second in five weeks to refute the claim that 113 human genes came to vertebrates through direct, or horizontal, transfer from bacteria. The original claim was published in February in the Nature paper on the human genome sequence.

In the current issue of Nature, researchers at GlaxoSmithKline, in Collegeville, Pennsylvania, say there is no evidence that bacterial genes have ever migrated to vertebrate genomes. The researchers conducted evolutionary, or phylogenetic, analyses for 28 of the 113 proposed human genes. The 28 human genes have counterparts in nonvertebrate species or are more closely related to species other than bacteria, according to the paper.

"We find absolutely no evidence of bacteria-to-vertebrate gene transfer for the set of 28 genes we analyzed, as well as for the other genes we're now working on," says Michael J. Stanhope, head of Evolutionary Biology, Bioinformatic Sciences, at GlaxoSmithKline. A research team led by Stanhope and James R. Brown constructed evolutionary trees for the 28 genes and is analyzing others in the original set of 113.

Last month, another research team published a study showing that the original claim was an error. Researchers at The Institute for Genomic Research (TIGR), in Rockville, Maryland, reported in Science Express that most of the proposed genes have counterparts in invertebrate databases. They trimmed the original list of candidates to about 40 human genes and said that none of these is likely to have been transferred from bacteria.

See related GNN article
»Researchers Challenge Recent Claim That Humans Acquired 223 Bacterial Genes During Evolution

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Stanhope, M.J. et al. Phylogenetic analyses do not support horizontal gene transfers from bacteria to vertebrates. Nature 411, 940-944 (June 21, 2001).
Salzberg, S.L. et al. Microbial genes in the human genome: lateral transfer or gene loss? Science 292, 1903-1906 (June 8, 2001). Published online May 17, 2001.
Lander, E.S. et al. Initial sequencing and analysis of the human genome. Nature 409, 860-921 (February 15, 2001).

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