Researchers Trade Insights About Gene Swapping

摘要

When research labs began churning out the genome sequences of a multitude of microbes in the late 1990s, microbiologists got a big surprise: Many organisms seem to be swapping genes with abandon from strain to strain, even across species. Astonishingly, for example, about 25% of the genome of the gut bacterium Escherichia coli turns out to have been acquired from other species. The realization that gene swapping, or horizontal gene transfer as it is called, is a common phenomenon has thrown the field into a tizzy. The implications, says microbiologist Matthew Kane of the National Science Foundation in Arlington, Virginia, "are very, very broad." Borrowed genes can spread antibiotic resistance from one pathogen to another or help an organism survive new or stressful conditions. And it happens often enough to alter the dynamics of microbial communities and even affect the course of evolution. For systematists trying to figure out the relationships between different organisms, however, gene transfer causes a big headache: It blurs the boundaries between species, making it difficult to determine where organisms belong on the family tree.