The Environmental Genomics Group works to characterize underlying factors that contribute to variability in human toxicological responses. We especially focus on discovery of human alleles or epigenetic factors that modify responses to exposure and we investigate how such factors affect risk in exposed people. This basic information will be useful in determining appropriate variability parameters in human risk estimation models, in identifying at-risk individuals and in devising disease-prevention strategies.
The NIEHS Environmental Genome Project and the 1000 Genomes Project have uncovered millions of sequence variants in the human genome. However, relatively few of these single nucleotide polymorphisms (SNPs) affect protein structure. Perhaps more SNPs will affect gene expression related to environmental stress responses, but methods for studying this are not established. The Environmental Genomics Group is developing novel methods to identify SNPs that regulate gene expression or that measure their functional impact in vitro and in vivo. Thus, the group's overall objective is to identify sequence variants that modulate exposure responses and to evaluate their roles in human susceptibility to environmentally-induced disease using a variety of functional approaches.
Epigenetics is the nongenetic transmission of gene regulation information from parent cell to daughter cells and from one generation to the next that is encoded in methyl-CpGs, histone modifications or noncoding RNAs. Epigenetic factors such as chromatin state may modulate the impact of exposure, or conversely, exposure can directly alter epigenetic status such as DNA methylation level in regulatory sequences (Joubert et al 2012). Determining the functional impact of exposure-induced changes in methylation is an active area of interest for our group.
Major Areas of Research:
Dr. Bell received a B.S. degree from Cornell University in 1975, and a Ph.D. in Environmental Biology from the University of North Carolina at Chapel Hill in 1988. Following postdoctoral fellowships at UNC-CH and U.S. Environmental Protection Agency he joined the National Institute of Environmental Health Sciences in 1990 becoming a Senior Investigator in 1996. He currently heads the Environmental Genomics Group in the Laboratory of Molecular Genetics, NIEHS.