Bacteria More Likely to Adopt “Loner” Genes

A new study of more than three dozen bacteria species — including the microbes responsible for pneumonia, meningitis, stomach ulcers and plague — settles a longstanding debate about why bacteria are more likely to steal some genes than others. While most organisms get their genes from their parents just as people do, bacteria and other single-celled creatures also regularly pick up genes from more distant relatives. This ability to 'steal' snippets of DNA from other species — known as lateral gene transfer — is responsible for the rapid spread of drug resistance among disease-causing bacteria. "By understanding why some genes are more likely to spread from one species to the next, we can better understand how new virulent bacterial strains emerge," said co-author Dr. Tal Pupko, a visiting scientist at the National Evolutionary Synthesis Center in Durham, North Carolina. Scientists have proposed several theories to explain why some bacterial genes are more likely to jump into other genomes. One theory, Dr. Pupko explained, is that it depends on what the gene does in the cell. Genes involved in core functions, like converting RNA into protein, are much less likely to make the leap. "If a species already has the basic molecular machinery for transcription and translation, there's no advantage to taking in another set of genes that do the same thing," Pupko said. Other studies suggest it's not what the gene does that matters, but how many proteins it interacts with – a network researchers have dubbed the 'interactome.' Genes involved in transcription and translation, for example, must work in concert with many partners to do their job.
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