Mapping the human epigenome is similar to the human genome project in the 1990s.
A research article published in the online edition of PLoS Genetics describes epigenetics, a relatively new endeavour in science, as the control of the patterns of gene expression in cells, which gives rise to the necessary differences responsible for creating the complex and interacting tissues in the body.
Scientists globally have begun working on a Human Epigenome Project in a bid to compile detailed data documenting, within a person, the epigenetic changes in different types of cells and tissues, something that will complement the already-completed Human Genome Project.
The Brown University researchers say that they have completed a far-reaching study of more than 200 human tissue samples in a bid to map variations in epigenomic structure.
They have carried out this work in collaboration with researchers from the Harvard School of Public Health and Harvard Medical School, the University of California-San Francisco, University of Minnesota-Minneapolis, Dartmouth Medical School, Women and Infants Hospital in Providence, and Brigham and Women's Hospital in Boston.
The researchers have found that human cells display wide epigenetic variation that appears related to aging and smoking, which may increase susceptibility to several diseases such as cancer.
While the scientists emphasize that more research is necessary, they say that taking a step to map epigenetic variability will help bring them closer to discovering important epigenetic differences in people, which in turn could help better diagnose disease and create more targeted treatments.
"Scientists have already found out it is critical to look at genetic variation to diagnose disease. What we are trying to do is complement that by looking at what is normal and how much variation in epigenetics exists," said Brock Christensen, a postdoctoral research associate at Brown University's Department of Pathology and Laboratory Medicine.
According to Christensen, more tissue samples and data are needed to allow for a thorough mapping of epigenetic variability in cells.
Karl Kelsey, corresponding author and a Brown professor of community health and pathology and laboratory medicine, says: The real importance of the work has to do with beginning to define what is normal in different tissues. And then you dig deeper to see what is the same and different about different people."
The study involved analysis of 217 nonpathologic human tissue samples, including blood, lung, head and neck, and brain tissue.
It was funded by multiple grants through the National Institutes of Health.