DIRECT ALLELIC VARIATION SCANNING OF THE YEAST GENOME

As more genomes are sequenced. the identification and characterization of the causes of heritable variation within a species will be increas ingly important. It is demonstrated that allelic variation in any two isolates of a species can be scanned, mapped, and scored directly and efficiently without allele-specific polymerase chain reaction. without creating new strains or constructs, and without knowing the specific nature of the variation. A total of 3714 biallelic markers, spaced abo ut every 3.5 kilobases, were identified by analyzing the patterns obta ined when total genomic DNA from two different strains of yeast was hy bridized to high-density oligonucleotide arrays. The markers were then used to simultaneously map a multidrug-resistance locus and four othe r Loci with high resolution (11 to 64 kilobases).