Metagenomics - Introduction

Human survival depends on the trillions of microbes that that inhabit our bodies. In a healthy person, those bacteria, fungi and viruses - the human microbiota - are well balanced. But shifts in the makeup and function of those populations can lead to diseases.

New approaches in metagenomics - which examines the genomic makeup of an entire organism, including its microbial communities - are now making such research possible.

Despite their critical role in human health, the vast microbial populations within humans are largely unexplored. IGS scientists are important players in an international effort - the Human Microbiome Project - to fill that knowledge gap.

We are not alone! Trillions of microbes (collectively known as the human microbiota) reside on and in the human body. Our bodies contain 10 times more microbial cells than human cells; the adult human colon alone contains up to 100 trillion bacteria.

Deepening the understanding of those microbial communities in places like the human gut will help scientists nail down their exact roles in health and disease. Such microbes encode metabolic pathways that are not present in human genomes, but that are essential for our survival.

Shifts in the makeup and function of these microbial populations can be associated with a number of acute and chronic diseases. These include inflammatory bowel disease, obesity, cardiovascular disease, eczema and other skin diseases, vaginal conditions and even certain types of cancer.

Jacques Ravel on Vaginal Microbiome

Most of these microbes are not the types that cause illness or infections. Rather, our bodies have evolved to work in concert with these organisms to help us digest many of the foods that we eat, break down toxic compounds we ingest on a daily basis and play an important role in keeping pathogenic organisms in check.

As IGS and other scientists reconsider a number of familiar diseases in the context of microbial ecology, exciting prospects emerge for designing, implementing, and monitoring strategies for intentionally manipulating the human microbiota to optimize our health.