Bacteria acquired up to 90 percent of their genetic material from distantly related bacteria species, according to new research from The University of Arizona in Tucson.

The finding has important biomedical implications because such gene-swapping, or lateral gene transfer, is the way many pathogenic bacteria pick up antibiotic resistance or become more virulent.

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Most commonly, genes are transmitted by bacteriophages, viruses that specifically hijack bacteria cells. Like tiny syringes, phages inject their own genetic material into the host cell, forcing it to produce new phages. During such an event, genes from the bacterial genome can be incorporated into the newly made phages. They inject their newly modified genetic load into other bacteria. This way, bacteriophages act as shuttles, taking up DNA from one bacterium and dumping it into another. Bacteria can also make contact by tiny connection tubes through which they exchange pieces of DNA. They can also take up genetic material from the environment.