Chirag Patel, Ph.D.
Harvard Medical School
According to a new NIEHS-funded study, the human body contains microbes with staggering genetic variation, much of which is unique to a single individual. The study, one of the largest of its kind, is the first to look at the DNA of bacteria that reside in both the mouth and the gut. Most previous research has focused on identifying the types of bacteria, rather than their full genome, providing only partial clues to how the microbiome is involved in disease and health.
The team aggregated publicly available microbiome data from nearly 4,000 samples from the human mouth and gut and used computational approaches to identify unique genes. Their analysis uncovered a massive universe of more than 45 million unique bacterial genes. Many of these were found in only one sample, pointing to vast genetic variation within bacterial strains. They reported that these unique genes could be profiled to act as microbial fingerprints, which may provide important information about past exposures.
Together, this information was used to build a publicly available microbiome gene catalog. According to the authors, cataloguing the array of microbial genes could help explain observed differences in human diseases in which the microbiome is known to play a role. The catalogue could also shed light on the interaction between genes and the environment that leads to health or disease.
Citation: Tierney BT, Yang Z, Luber JM, Beaudin M, Wibowo MC, Baek C, Mehlenbacher E, Patel CJ, Kostic AD. 2019. The landscape of genetic content in the gut and oral human microbiome. Cell Host Microbe 26(2):283−295.e8.