The recent concerted effort by the Human Genome Project to identify and characterize large numbers of single-nucleotide polymorphisms (SNPs), coupled with the development of automated scanners capable of reading and assigning large numbers of SNP genotypes simultaneously on chip microarrays, promises to revolutionize procedures of gene mapping and gene identification, especially for genes involved in causing common, complex diseases such as diabetes, autoimmune disease, schizophrenia, heart disease, and many others. The Human Medical Genetics Program of the University of Colorado Health Sciences Center (UCHSC) has established and operates a Genotyping/Gene Mapping Core facility that provides gene mapping expertise and service to many investigators at UCHSC and its affiliated institutions. The purpose of this proposal is to purchase an Affymetrix GeneChip Instrument System for the UCHSC Genotyping/Gene Mapping Core facility so that SNP genotyping technology can be made available to all investigators at UCHSC and its affiliated institutions who need to utilize this major new extension of approaches to gene mapping and epidemiology.