Putative Ancestral Origins of Chromosomal Segments in Individual African Americans: Implications for Admixture Mapping

  1. Michael F. Seldin1,4,
  2. Takanobu Morii1,
  3. Heather E. Collins-Schramm1,
  4. Bill Chima1,
  5. Rick Kittles2,
  6. Lindsey A. Criswell3, and
  7. Hongzhe Li1
  1. 1 Rowe Program in Human Genetics, Departments of Biological Chemistry and Medicine, University of California at Davis, Davis, California 95616-8669, USA
  2. 2 National Human Genome Center at Howard University, Washington, District of Columbia 20060, USA
  3. 3 Rosalind Russell Medical Research Center for Arthritis, University of California at San Francisco, San Francisco, California 94143, USA

Abstract

Theoretically, markers that distinguish European from West African ancestry can be used to examine the origin of chromosomal segments in individual African Americans. In this study, putative ancestral origin was examined by using haplotypes estimated from genotyping 268 African Americans for 29 ancestry informative markers spaced over a 60-cM segment of chromosome 5. Analyses using a Bayesian algorithm (STRUCTURE) provided evidence that blocks of individual chromosomes derive from one or the other parental population. In addition, modeling studies were performed by using hidden real marker data to simulate patient and control populations under different genotypic risk ratios. Ancestry analysis showed significant results for a genotypic risk ratio of 2.5 in the African American population for modeled susceptibility genes derived from either putative parental population. These studies suggest that admixture mapping in the African American population can provide a powerful approach to defining genetic factors for some disease phenotypes.

Footnotes

  • Article and publication are at http://www.genome.org/cgi/doi/10.1101/gr.2165904. Article published online before print in May 2004.

  • 4 Corresponding author. E-MAIL mfseldin{at}ucdavis.edu; FAX (530) 754-6015.

    • Accepted February 19, 2004.
    • Received November 12, 2003.
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