About the Authors

Noah A Rosenberg

To whom correspondence should be addressed. E-mail: rnoah@umich.edu

Affiliation Department of Human Genetics, Bioinformatics Program, and the Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, United States of America

Saurabh Mahajan

Affiliation Department of Computer Science, University of Southern California, Los Angeles, California, United States of America

Sohini Ramachandran

Affiliation Department of Biological Sciences, Stanford University, Stanford, California, United States of America

Chengfeng Zhao

Affiliation Mammalian Genotyping Service, Marshfield Clinic Research Foundation, Marshfield, Wisconsin, United States of America

Jonathan K Pritchard

Affiliation Department of Human Genetics, University of Chicago, Chicago, Illinois, United States of America

Marcus W Feldman

Affiliation Department of Biological Sciences, Stanford University, Stanford, California, United States of America

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

The initial approach was conceived by NAR, with help from JKP and MWF. The construction of subsamples with different levels of geographic dispersion was performed by SM and NAR. CZ contributed to the design and construction of the marker panels and to initial analysis with STRUCTURE; the full STRUCTURE analysis was designed by NAR and SM, with help from JKP, and was performed by SM with help from NAR. The regression analyses were designed by NAR with help from MWF, and were performed by NAR. The genetic/geographic distance analysis was designed by SR and NAR and was performed by SR. NAR wrote the paper with help from SR, JKP, and MWF.