"All our knowledge had been based on what we could culture in the laboratory," Segre said. "Culturing puts a bias on what you can study. You're limited to what you can grow at a certain temperature in enriched media. In culture, you can find what you are looking for, but it's hard to find what is not there."
Even more unexpected was the similarity of the bacteria living in the same sites on different people. "We found that the site was more determining than the individual," Segre said. "In different people's armpits we found the same bacteria, while different parts of the body had very different bacteria."
Diversity is to be expected in bacteria because there are a lot of different species, and now that diversity can be explored in depth, she said. "A revolution in sequencing technology enables us to obtain information of a complexity that is astronomical compared to what was possible just a few years ago," said Segre, who began to work in the Human Genome Project as a graduate student.
"This is fundamental work, defining one aspect of human biology," said Dr. Martin Blaser, chairman of medicine and a microbiologist at New York University, who has done several studies of human skin bacteria. "The human body is a map, and they are putting more sites on the map. This has been a very good advance."
Blaser and his colleagues have published several studies of bacteria that they found on the human forearm. "We began to use molecular methods several years ago, and we continue to do that," he said. "This work is much more comprehensive that ours were, because the tools are more powerful."
Though the new study can be described as basic science, "the identification of complex microbiota is important if one considers many inflammatory diseases of
All rights reserved