title: Modeling the 3D geometry of the cortical surface with genetic ancestry.
abstract: Knowing how the human brain is shaped by migration and admixture is a critical step in studying human evolution [1, 2], as well as in preventing the bias of hidden population structure in brain research [3, 4]. Yet, the neuroanatomical differences engendered by population history are still poorly understood. Most of the inference relies on craniometric measurements, because morphology of the brain is presumed to be the neurocranium's main shaping force before bones are fused and ossified [5]. Although studies have shown that the shape variations of cranial bones are consistent with population history [6-8], it is unknown how much human ancestry information is retained by the human cortical surface. In our group's previous study, we found that area measures of cortical surface and total brain volumes of individuals of European descent in the United States correlate significantly with their ancestral geographic locations in Europe [9]. Here, we demonstrate that the three-dimensional geometry of cortical surface is highly predictive of individuals' genetic ancestry in West Africa, Europe, East Asia, and America, even though their genetic background has been shaped by multiple waves of migratory and admixture events. The geometry of the cortical surface contains richer information about ancestry than the areal variability of the cortical surface, independent of total brain volumes. Besides explaining more ancestry variance than other brain imaging measurements, the 3D geometry of the cortical surface further characterizes distinct regional patterns in the folding and gyrification of the human brain associated with each ancestral lineage.
authors.affiliation: Department of Cognitive Science, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA.
authors.forename: Chun Chieh
authors.initials: CC
authors.lastname: Fan
authors.affiliation: Multimodal Imaging Laboratory, University of California, San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA 92037, USA.
authors.forename: Hauke
authors.initials: H
authors.lastname: Bartsch
authors.affiliation: Department of Cognitive Science, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Schork
authors.affiliation: Department of Radiology, University of California, San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA 92037, USA.
authors.forename: Chi-Hua
authors.initials: CH
authors.lastname: Chen
authors.affiliation: Multimodal Imaging Laboratory, University of California, San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA 92037, USA; Norwegian Centre for Mental Disorders Research (NORMENT), KG Jebsen Centre for Psychosis Research, Institute of Clinical Medicine, University of Oslo, 0424 Oslo, Norway; Department of Neuroscience, University of California, San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA 92037, USA.
authors.forename: Yunpeng
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Radiology, University of California, San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA 92037, USA.
authors.forename: Min-Tzu
authors.initials: MT
authors.lastname: Lo
authors.affiliation: Multimodal Imaging Laboratory, University of California, San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA 92037, USA; Department of Neuroscience, University of California, San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA 92037, USA.
authors.forename: Timothy T
authors.initials: TT
authors.lastname: Brown
authors.affiliation: Multimodal Imaging Laboratory, University of California, San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA 92037, USA; Department of Radiology, University of California, San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA 92037, USA.
authors.forename: Joshua M
authors.initials: JM
authors.lastname: Kuperman
authors.affiliation: Multimodal Imaging Laboratory, University of California, San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA 92037, USA; Department of Radiology, University of California, San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA 92037, USA.
authors.forename: Donald J
authors.initials: DJ
authors.lastname: Hagler
authors.affiliation: J. Craig Venter Institute, Capricorn Lane, La Jolla, CA 92037, USA.
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Schork
authors.affiliation: Department of Cognitive Science, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA; Department of Radiology, University of California, San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA 92037, USA; Center for Human Development, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92161, USA; Department of Psychiatry, University of California, San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA 92037, USA.
authors.forename: Terry L
authors.initials: TL
authors.lastname: Jernigan
authors.affiliation: Department of Cognitive Science, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA; Multimodal Imaging Laboratory, University of California, San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA 92037, USA; Department of Radiology, University of California, San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA 92037, USA; Department of Neuroscience, University of California, San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA 92037, USA; Department of Psychiatry, University of California, San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA 92037, USA. Electronic address: amdale@ucsd.edu.
authors.forename: Anders M
authors.initials: AM
authors.lastname: Dale
mesh_terms: D000293:Adolescent; D001837:Body Weights and Measures; D001921:Brain / Q000033:anatomy & histology*; D005260:Female; D051456:Gene Flow; D000068617:Genetic Background; D006801:Humans; D008297:Male; D008959:Models, Neurological; D020641:Polymorphism, Single Nucleotide; D025341:Principal Component Analysis; D014481:United States; D055815:Young Adult