Duplications of Noncoding DNA May Have Affected Evolution of Human-Specific Traits

Duplications of large segments of noncoding DNA in the human genome may have contributed to the emergence of differences between humans and nonhuman primates, according to results presented on October 18, 2017 at the American Society of Human Genetics (ASHG) 2017 Annual Meeting in Orlando, Florida. Identifying these duplications, which include regulatory sequences, and their effect on traits and behavior may help scientists explain genetic contributions to human disease. Paulina Carmona-Mora, PhD, who presented the work; Megan Dennis, PhD; and their colleagues at the University of California, Davis, study the history of human-specific duplications (HSDs), segments of DNA longer than 1,000 base pairs that are repeated in humans but not in primates or other animals. In this study, they focused on HSD regions that do not code for genes, but instead regulate the expression of other genes. “What’s special about these regulatory elements is that they have the propensity to impact the expression of genes nearby on the same chromosome, as well as elsewhere in the genome,” said Dr. Dennis. “This means that one duplication could affect many genes, amplifying its impact.” Because duplicated segments are more than 98% identical, it is difficult to distinguish between them, Dr. Dennis explained.
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