A Matter of Health

Sequencing bacteria

By Ruth SoRelle, M.P.H.

The fanfare that accompanied the stages of the Human Genome Project were lacking, but when the Human Microbiome Project was inaugurated this year as a National Institutes of Health Roadmap initiative, science opened the door to a new understanding of human health and the origin of disease.

Why is it important?

Hundreds of species of bacteria

Human beings are colonized by hundreds of species of bacteria. As George Weinstock, Ph.D., co-director of the Baylor College of Medicine Human Genome Sequencing Center and a prime mover in the Human Microbiome Project puts it, "I have 20,000 genes in my genome, and all my cells have the same genes. Each bacterium has on the order of 1,000 genes, but there are thousands of species of bacteria, each with different genes. There are millions of bacterial genes in you and me. Collectively, those bacterial genes are a metagenome. You carry them with you, and the action of their genes affects you. There are 10 times more microbial cells than there are human cells. You and I are basically a big microbial community."

Most of those microbes are not harmful, and many are beneficial. For example, we need many of the bacteria found in our gut.

Moving evolution

Micro-organisms move evolution, Weinstock said. "Most primitive cells such as amoeba are colonized by bacteria. Nothing has happened in evolution that didn't have bacteria and viruses crawling all over it."

The bacteria bind to the proteins in our bodies – collagen, keratin and others. They interact with the proteins within the body. Understanding the effects of those interactions and how they even occur is part of the goals of scientists involved in the microbiome project.

The scale of the project is immense, but technology has come far since the Human Genome Project started in the mid-1980s. The first bacterial genome was sequenced in 1995, but the speed of sequencing had to increase to meet the huge demands of a project such as this.

BCM part of plan

Baylor College of Medicine Human Genome Sequencing Center, Washington University in St. Louis, the Broad Institute and the J. Craig Venter Institute received the first round of funding for this venture.

"The Human Microbiome Project seeks to describe the microbial community that colonizes you," said Weinstock. "It seeks to understand how it changes and to correlate these changes with health and disease. It could offer new opportunities for early diagnosis, treatments and therapies."