Gene Duplications Associated with Autism Evolved Recently in Human History

Human geneticists have discovered that a region of the genome associated with autism contains genetic variation that evolved in the last 183,000 years, after the divergence of humans from ancient hominids, and likely plays an important role in autism and other diseases. The findings were presented on Saturday evening, October 18, at the opening of the American Society of Human Genetics (ASHG) 2014 Annual Meeting in San Diego, California. Researchers at the University of Washington analyzed the genomes of 2,551 humans, 86 great apes, one Neanderthal, and one Denisovan. The scientists closely examined a region of human chromosome 16 known as 16p11.2, where recurrent deletions and duplications that are major contributors to autism, and also associated with schizophrenia and extremes of body mass and head circumference, occur. Approximately 1% of individuals with simplex autism have deletions or duplication at 16p11.2. These events occur via nonallelic homologous recombination between directly oriented segmental duplications approximately 600 kilobase pairs apart, the presenter, Xander Nuttle, B.S., B.S.E., the first author of the report said. The research team found that certain segments of DNA in this region are repeated a variable number of times in different people and may also be associated with disease. To trace the origins of this variation, the researchers collaborated with colleagues at the University of Lausanne in Switzerland and the University of Bari in Italy to sequence and analyze corresponding regions of ape genomes. Mr.
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