A Whole Genome Admixture Scan for Type 2 Diabetes in African Americans

Project leaders

David Reich, Broad Institute, Harvard (principal investigator)
Jim Wilson, Jackson Heart Study (principal investigator)
Herman Taylor, Jackson Heart Study
Brian Henderson, Multi-Ethnic Cohort
Laurence Kolonel, Multi-Ethnic Cohort

Project Members

Gavin McDonald, Broad Institute
Meggie (Ermekgul) Akylbekova. Jackson Heart Study

Project Overview

Admixture mapping is a method for genome-wide association analysis based on admixture-generated linkage disequilibrium. Our collaborative group has identified 1,478 African Americans with Type 2 Diabetes (T2D) from the Jackson Heart Study and Multiethnic Cohort Study, as well as 498 controls from the Jackson Heart Study who are normoglycemic despite high body mass index and older age.

All samples were genotyped (using the Illumina BeadLab platform[i] ) for 1,291 polymorphic markers chosen to be extremely different in frequency between west Africans and European Americans[ii,iii]. Evidence for association to diabetes at each marker as reported by the ANCESTRYMAP software[iv] are reported in the downloadable table.

We calculate that this study has statistical power to detect loci where African or European ancestry on average confers multiplicative increased risk of 1.35-fold or more[iv]. The fact that we did not detect a statistically significant signal of association in the scan suggests that any genetic risk factors for T2D do not confer different risks due to ancestry that differ by this factor.

Study Design and Methods


A Note about early access to the data:
We are making the genome scan results publicly available prior to publication so that researchers interested in the genetics of T2D can use the results of the scan to prioritize follow-up of any regions of interest. We plan to publish the results of the scan, with much more detailed discussion, in due time.

  • Summary
  • Detailed results (Excel)
    Admixture Scan Results per SNP in African Americans table. In this table we give detailed results at each of 1,291 markers included in our scan. This should be of use to researchers who are interested in combining the data from our scan with data from other sources, to prioritize genomic regions of interest for Type 2 Diabetes risk. If we or others carry out future admixture scans of African American Type 2 Diabetes cases, it will also be important to combine the results of these analyses with those of other scans to increase power to detect T2D risk loci. For example, increasing sample size to ~5,000 African Americans with T2D should allow power to detect loci conferring risk as little as 1.2-fold due to ancestry
  • ANCESTRY MAP Software
  • References