Ancestry Informative Markers
To apply admixture mapping, a set of genetic markers called AIMs, provide information at each locus of the ancestral origin of the allele. An AIM is a polymorphic locus that exhibits substantially different allele frequencies between the ancestral populations, which are often from different geographical regions. For example, Fig. 1 shows an allele frequency distribution of 9,781 AIMs screened from genomewide SNPs from European (EUR) and East Asian (EAS) populations. With a set of AIMs, one can estimate the geographical origins of the ancestors of an individual and ascertain what proportion of the ancestry is derived from each geographical region. The primary utility of estimates of continental ancestry using AIMs is to control for confounding from population stratification in genetic association studies among unrelated individuals from admixed populations. Population admixture has the potential to lead to confounding results from population stratification in genetic association studies, leading to both false positive (type I error) and false negative (type II error) results [36-39]. Now, to facilitate the application of admixture mapping, a number of high-density mapping panels have been constructed, Such panels are already available for disease gene discovery in AfAs [16, 21, 40, 41], Hispanics/Latinos [23, 26, 40], Mexican-Americans (the largest subgroup of Hispanic/Latinos) [28, 41], and Uyghurs [35].