The Human Microbiome Project
Within the body of a healthy adult, it is estimated that the cells of microbes outnumber human cells by a factor of ten to one. These communities of microscopic organisms, however, remain largely unstudied, leaving almost entirely unknown their influence upon human development, physiology, immunity, and nutrition.
Balintfy: Microbes are tiny organisms.
Segre: Those are organisms that you typically can only see if you look under a microscope.
Balintfy: Dr. Julia Segre at the National Human Genome Research Institute explains that microbes—which can be bacteria, viruses, fungi, or protozoa—live everywhere.
Segre: What's amazing there is that if you sample soil or water, you’ll find about 100 different bacterial phylum; only about seven or eight can live in and on the human.
Balintfy: Some microbes cause disease. Others are essential for a healthy life. Traditionally scientists have focused on the study of specific kinds of microbes. But now researchers are taking advantage of recent technological advances to better understand the entire microbiome.
Segre: The definition of the microbiome is the DNA of all of the small organisms that live in and on our body.
Balintfy: Dr. Segre explains that scientists now appreciate that a lot of the functions of a human body are actually carried out by these small organisms. Digestion is one example. So research is expanding to investigate not only human DNA, but also the DNA of all of the microbes that live on and in us.
Segre: So, we have to think about it with this layer of complexity that the bacteria and the fungi are really interacting with each other. They’re interacting with the human cells and that it is a community of organisms that are together creating this protein encoding potential that could vastly exceed our own human cells.
Balintfy: To generating resources to understand the microbiome and analyze its role in health and disease, the NIH has launched The Human Microbiome Project. Dr. Segre says the project involves collecting and sequencing all the DNA they can find.
Segre: And then we have to piece back together what DNA came from which of these different organisms. It’s as if a spaceship landed in Washington, D.C. and took DNA from everyone who was walking through the intersection at once. And we do understand that that DNA belongs to 100 different people, but we are sampling it as if we’re getting those 100 people all together. And we’re thinking about the bacteria for the first time now not as separate organisms, but how they form a community. Because our human cells all have the same protein encoded potential, the DNA of every human cell is the same, but the DNA of every bacteria could be different.
Balintfy: A goal of this kind of research Dr. Segre adds, is personalize medicine: to determine the best treatment for a specific individual to stay healthy and perhaps treat or prevent a disease. For more information about the Human Microbiome Project, visit the website: nihroadmap.nih.gov/hmp. This is Joe Balintfy, National Institutes of Health, Bethesda, Maryland.