It doesn't take much to be a vile, bloodsucking pest. You, human, have three billion base pairs in your genome, but the body louse—which has been a typhus-spreading scourge of humanity for millennia—carries just 108 million. That's what scientists say today in a study in the Proceedings of the National Sciences that describes how they sequenced the body louse genome. Because the body louse (a separate creature from the head or pubic louse) lives entirely on humans, hatching in our clothes and eating our blood, its genome can get away with being so streamlined, study author Barry Pittendrigh says:
"Most of the genes that are responsible for sensing or responding to the environment are very much reduced," Pittendrigh said. The body louse was found to have "significantly fewer genes" for smell and taste, as well as minimal genes responsible for a "simple visual system," the study authors wrote. They found ...
