What makes you different from every other human being? The best place to look for an answer may not be in your genes, but in the sequences of DNA between them, according to a team of researchers reporting in the journals Science Express and Nature.
While genes provide instructions for making the proteins that do specific tasks inside a cell, the sequences surrounding them help regulate how those instructions are carried out. These non-coding sequences make up about 98% of our genome. They vary from 1% to 4% among all humans, in contrast to genes, which vary only about .025%. According to the new studies, such slight variations among individuals are enough to affect how well specialized proteins, called transcription factors, bind to the non-coding DNA sequences. By comparing variations in protein binding among ten people and one chimpanzee, researchers found that differences in binding can change the way neighboring genes are expressed. The results suggest that much more of our DNA than just our genes determine how we look, who we become, and the kinds of diseases for which we’re at risk.
Kasowski, Maya et al. 'Variation in Transcription Factor Binding Among Humans.' Science Express. March 18, 2010.
Zheng,Wei et al. 'Genetic analysis of variation in transcription factor binding in yeast.' Nature. March 17, 2010.