American scientists have identified over 4,200 species of bacteria that live in various parts of a human body and mapped them into an atlas.
The researchers at the University of Colorado, Boulder, also found unexpectedly wide variations in bacterial communities from person to person.
"Not only did the bacterial communities vary from person to person, they also varied considerably from one site on the body to another, and from test to test - but some patterns did emerge," said Rob Knight, the lead researcher.
"This is the most complete view we have yet of the microbial side of ourselves, one that our group and others will be adding to over the coming years," he said.
Hoping that their work will eventually aid clinical research, the scientists say it might be one day possible to identify sites on the human body where transplants of specific microbes could benefit health, according to 'Science Express' journal.
"The goal is to find out what is normal for a healthy person, which will provide a baseline for further studies to look at people with diseased states," the research team said.
The study was based on an intensive analysis of the bacteria found at 27 separate sites on the bodies of nine healthy volunteers.
There are an estimated 100 trillion microbes living on or inside the human body and they are thought to play a key role in many physiological functions, including development of the immune system.
