Mapping of four ras superfamily genes by physical and genetic means in Schizosaccharomyces pombe.

Four ras superfamily genes, namely ypt1, ypt2, ypt3 and ryh1, have been located on the S. pombe linkage map. This was achieved by constructing strains carrying a new NotI cutting site and the S. cerevisiae LEU2 gene integrated next to the respective gene. The physical location of these genes of the chromosomes was then determined by NotI restriction analysis of the DNA prepared from each strain. Fine genetic mapping was carried out by conventional tetrad analysis using the integrated LEU2 gene as a marker. The results indicated that ypt1 is tightly linked to top1 on the right arm of chromosome II; that ypt2 is 2.5 cM apart from ura2 on the right arm of chromosome I; that ypt3 is tightly linked to arg3 on the left arm of chromosome I; and that rhy1 is located approximately 20 cM from ade3 on the left arm of chromosome I.