This is an individual National Research Service Award for post-doctoral research training, which provides support for promising Fellowship Applicants with the potential to become productive, independent investigators in scientific health-related research fields. Population genetics is a crucial tool for facilitating medical genetics and disease gene mapping studies. This proposal includes two novel population genetic techniques that each facilitate disease gene mapping in different ways. First, a probabilistic technique for detecting the proportion of homozygosity (having two identical alleles of the same gene) an individual is likely to have based on single nucleotide polymorphism (SNP) microarray data will be used. This method is useful for prioritizing disease case sample individuals for whole genome sequencing and subsequent homozygosity mapping to identify recessive disease genes. This scheme will be applied to a dataset of individuals with autism to identify individuals that will be the best candidates to resequence their genes and perform homozygosity mapping to locate recessive disease genes. The second part of the project will develop methods to permit combined admixture mapping and genome-wide association (GWA) of Latinos, a population for which current admixture mapping methods fail. This will be applied to study the genetics of type 2 diabetes, a disease with higher prevalence among Latinos. The technology developed through these two methods will be applicable to a variety of disease gene mapping studies.