Classifying people and how - DNA, fingerprint, blood types and now this!!

22nd April 2011

Introduction: How to classify people? based on their DNA, blood type, finger print, pupil (as in the eye), tastebuds and now this!! very interesting! Check it out - people classified based on the gut bacteria! Also available here

Scientists find gut bacteria classifies people into three types

In the early 1900s, scientists discovered that each person belonged to one of four blood types . Now they have discovered a new way to classify humanity: by bacteria. Each human being is host to thousands of different species of microbes . Yet a group of scientists now report just three distinct ecosystems in the guts of people they have studied.

"It's an important advance," said Rob Knight , a biologist at the University of Colorado , who was not involved in the research. "It's the first indication that human gut ecosystems may fall into distinct types."

The research team, led by Peer Bork of the European Molecular Biology Laboratory in Heidelberg, Germany, found no link between what they call enterotypes and the ethnic background of the European, American and Japanese subjects they studied.

Nor could they find a connection to sex, weight, health or age. They are now exploring other explanations. One possibility is that the guts, or intestines, of infants are randomly colonized by different pioneering species of gut microbes. The microbes alter the gut so that only certain species can follow them.

Whatever the cause of the different enterotypes, they may end up having discrete effects on people's health. Gut microbes aid in food digestion and synthesize vitamins, using enzymes our own cells cannot make.

Bork and his colleagues have found that each of the types makes a unique balance of these enzymes. Enterotype 1 produces more enzymes for making vitamin B7 (also known as biotin), for example, and Enterotype 2 more enzymes for vitamin B1 (thiamine).

Bork notes more testing is necessary. Researchers will need to search for enterotypes in people from African, Chinese and other ethnic origins. He also notes that so far, all the subjects come from industrial nations, and thus eat similar foods. "This is a shortcoming," he said. "We don't have remote villages."

In the recent work, Bork and his team carried out an analysis of the gut microbes in 22 people from Denmark, France, Italy and Spain. Some of their subjects were healthy, while others were obese or suffered from intestinal disorders like Crohn's disease. Bork and his colleagues searched for fragments of DNA corresponding to the genomes of 1,511 different species of bacteria. The researchers combined their results with previous studies of 13 Japanese individuals and four Americans.

The scientists then searched for patterns. And, as Bork and his colleagues reported on Wednesday in the journal Nature, each of the three enterotypes was composed of a different balance of species. People with type 1, for example, had high levels of bacteria called Bacteroides. In type 2, on the other hand, Bacteroides were relatively rare, while the genus Prevotella was unusually common.

Bork and his colleagues found confirmation of the three enterotypes when they turned to other microbiome surveys, and the groups continue to hold up now that they have expanded their own study to 400 people.