A quarterly publication of the Autism Research Institute
Winter, 2019 | Number 1, Volume 33
A little-studied part of the human genome may influence the severity of autism symptoms, according to a new study.
James Sikela and colleagues are investigating a region of the genome that encodes most copies of the Olduvai protein domain, a gene coding family that helped to spur the rapid evolution of humans. Their theory is that there was a trade-off for this evolutionary progress in the form of conditions such as autism and schizophrenia.
In their latest study, the researchers analyzed the genomes of individuals with autism and found that as the number of copies of Olduvai increased, the severity of autism symptoms increased as well. The research replicates two earlier studies by the team. Sikela says, “We hope that by showing that the link with autism severity holds up in three independent studies, we will prompt other autism researchers to examine this complex family.”
While many scientists are investigating the role of genes in autism, Sikela and colleagues note, “Even whole-genome sequencing approaches are limited in their ability to accurately assemble and measure changes in complex, highly duplicated genomic regions, and there are sequences in the genome, among them dynamic, high copy number gene coding regions [such as Olduvai], that are missed by each of these methods.”
The researchers propose that “Olduvai sequences can play both a beneficial role (in brain evolution and cognition) and a detrimental role (in autism and schizophrenia), and which outcome occurs depends on which, where, how, and when copies are changing.” They say this may explain why autism and schizophrenia, which tend to adversely affect survival and reproduction, persist at a high frequency across human populations.
DUF1220) copy number and severity of the classic symptoms of inherited autism,” Jonathan M. Davis, Ilea Heft, Stephen W. Scherer, and James M. Sikela, American Journal of Psychiatry, February 15, 2019 (online). Address: James Sikela, [email protected].
—and—
“Genomic trade-offs: are autism and schizophrenia the steep price of the human brain?”, James M. Sikela and V. B. Searles Quick, Human Genetics, January 15, 2018 (online). See address above.
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“New study shows hidden genes may underlie autism severity,” news release, University of Colorado Anschutz Medical Campus, February 15, 2019.
