The Healthy Human Microbiome

"Researchers have mapped the normal bacteria that live in and on the healthy human body. The accomplishment sets the stage for better understanding how bacterial communities affect human health and disease... The scientists found that more than 10,000 microbial species occupy the human body. They estimated that the microbiome provides more genes that contribute to human survival than the human genome itself provides (8 million vs. 22,000). [emphasis ours] Humans need bacterial genes to aid in basic processes such as digestion."