More than 15 years after scientists first mapped the human genome, most diseases still cannot be predicted based on one's genes, leading researchers to explore epigenetic causes of disease. But the study of epigenetics cannot be approached in the same way as genetics, so progress has been slow. Now, researchers at the USDA/ARS Children's Nutrition Research Center at Baylor College of Medicine and Texas Children's Hospital have determined a unique fraction of the genome that scientists should focus on. Their report, which provides a "treasure map" to accelerate research in epigenetics and human disease, was published online on June 3, 2019 in Genome Biology. The open-access article is titled “A Genomic Atlas of Systemic Interindividual Epigenetic Variation in Humans.” Epigenetics is a system for molecular marking of DNA that tells the different cells in the body which genes to turn on or off in that cell type. But the cell-specific nature of epigenetics makes it challenging to study. Whereas a blood sample can be used to “genotype” an individual, most epigenetic marks in blood DNA provide no clues about epigenetic dysregulation in other parts of the body, such as the brain or heart. The authors note the following. “DNA methylation is thought to be an important determinant of human phenotypic variation, but its inherent cell type specificity has impeded progress on this question. At exceptional genomic regions, interindividual variation in DNA methylation occurs systemically. Like genetic variants, systemic interindividual epigenetic variants are stable, can influence phenotype, and can be assessed in any easily biopsiable DNA sample. We describe an unbiased screen for human genomic regions at which interindividual variation in DNA methylation is not tissue-specific.”Login Or Register To Read Full Story