Genetics: Early Online, published on November 21, 2019 as 10.1534/genetics.119.302782 1 The Driver of Extreme Human-Specific Olduvai Repeat Expansion Remains Highly Active in the Human 2 Genome 3 Ilea E. Heft,1,* Yulia Mostovoy,2,* Michal Levy-Sakin,2 Walfred Ma,2 Aaron J. Stevens,3 Steven 4 Pastor,4 Jennifer McCaffrey,4 Dario Boffelli,5 David I. Martin,5 Ming Xiao,4 Martin A. Kennedy,3 5 Pui-Yan Kwok,2,6,7 and James M. Sikela1 6 7 1Department of Biochemistry and Molecular Genetics, and Human Medical Genetics and 8 Genomics Program, University of Colorado School of Medicine, Aurora CO 80045 9 2Cardiovascular Research Institute, 6Department of Dermatology, and 7Institute for Human 10 Genetics, University of California, San Francisco, San Francisco, CA, USA 11 3Department of Pathology, University of Otago, Christchurch, New Zealand 8140 12 4School of Biomedical Engineering, Drexel University, Philadelphia, PA 19104 13 5Children's Hospital Oakland Research Institute, Oakland, CA, 94609 14 15 Corresponding author: James M. Sikela:
[email protected] 16 *Ilea E. Heft and Yulia Mostovoy contributed equally to this article. 17 1 Copyright 2019. 18 Abstract 19 Sequences encoding Olduvai protein domains (formerly DUF1220) show the greatest 20 human lineage-specific increase in copy number of any coding region in the genome and have 21 been associated, in a dosage-dependent manner, with brain size, cognitive aptitude, autism, 22 and schizophrenia. Tandem intragenic duplications of a three-domain block, termed the Olduvai 23 triplet, in four NBPF genes in the chromosomal 1q21.1-.2 region are primarily responsible for 24 the striking human-specific copy number increase.