The increasing abundance of sequence data has facilitated the task of mapping genetic traits in several organisms by expanding the number of highly informative locus-specific markers for linkage analysis. However, the need exists for efficient, cost-effective methods for high-resolution genetic mapping. Genomic mismatch scanning (GMS) is a technique that utilises mismatch repair enzymes from Escherichia coli to screen for polymorphisms between genomic DNA samples from related individuals to select for regions of identity by descent (IBD) simultaneously. Regions of IBD selected by GMS are identified by hybridisation to a microarray of mapped DNA elements. No prior knowledge of the location of sequence polymorphisms within the population is required. To examine the ability of GMS to map genetic traits on a genome-wide scale, we performed selections for regions of IBD between multiple parent/segregant pairs of Saccharomyces cerevisiae to define candidate regions for loci of single and multigenic traits. DNA recovered from GMS of reciprocal parent/segregant pairs was amplified, differentially labelled with fluorescent probes and hybridised to microarrays containing all known yeast open reading frames. The degree of selection for regions of IBD was sufficient to allow determination of the parental genotype for approximately 85% of all open reading frames within the genome of each segregant based on a threshold ratio of 1.25. Our study results demonstrated that GMS was able to identify correct regions of the genome for all single gene traits examined. We were also able to identify two candidate regions for a multigenic trait predicted to result from the inheritance of two alleles.
This is a preview of subscription content, access via your institution