Over the last decade, geneticists studying how variations in DNA sequence between individuals can influence disease risk and other traits have largely focused on one type of variation: single-letter changes. Now a new study reveals how larger genetic modifications also significantly contribute to human traits.
The study, from researchers at the Broad Institute of MIT and Harvard, Brigham and Women’s Hospital, and Harvard Medical School, found that genetic changes called variable number tandem repeats (VNTRs) are strongly associated with nearly two dozen traits, including height, hair curl, and risk for heart and kidney disease. VNTRs are sections of the genome that stretch from seven up to thousands of base pairs in length, and are repeated a varying number of times in different individuals.
The team expected to see some associations between VNTRs and traits, but were surprised by how strong those links were. “The VNTRs we studied wound up being the top or second biggest genomic contributor to a trait,” said Po-Ru Loh, an associate member of the Broad Institute, an assistant professor at Harvard Medical School, and co-senior author of the study. “That really was a surprise.”
The results, published in Science, pave the way toward a deeper genetic understanding of how genetics affects human traits and disease, and also point to a new way for scientists to study larger-scale genetic repeat variation.
