Single-Nucleotide Polymorphism Genotyping in DNA Pools

To undertake partial, or complete, genome screens by association-based methodology for quantitative trait loci, multiple individuals have to be screened for large numbers of genetic markers. Consequently, much recent interest has focused on methods enabling accurate allele quantification in pooled deoxyribonucleic acid (DNA) samples. Microsatellites were the favored markers in initial studies, but the extraordinary wealth of data concerning single-nucleotide polymorphisms (SNPs) has turned attention to the quantification of SNP alleles in pools. All such approaches require accurate estimation of DNA concentrations, followed by the preparation of replicate pools, their validation, and application of procedures for determining allele frequencies. This chapter describes the important steps in preparing pools and surveys a variety of techniques that have been proposed for SNP detection. Finally, we describe the application of a generic approach using pooled DNA for detection of allele frequency differences between case and control populations based on primer extension protocols and outline a strategy for estimating SNP allele frequencies employing microarrays.