A RAT GENETIC-MAP CONSTRUCTED BY REPRESENTATIONAL DIFFERENCE ANALYSISMASKERS WITH SUITABILITY FOR LARGE-SCALE TYPING

Representational difference analysis (RDA) was applied to isolate chro mosomal markers in the rat. Four series of RDA [restriction enzymes, B amHI and HindIII; subtraction of ACI/N (ACI) amplicon from BUF/Nac (BU F) amplicon and vice versa] yielded 131 polymorphic markers; 125 of th ese markers were mapped to all chromosomes except for chromosome X. Th is was done by using a mapping panel of 105 ACI x BUF F-2 rats. To com plement the relative paucity of chromosomal markers in the rat, geneti cally directed RDA, which allows isolation of polymorphic markers in t he specific chromosomal region, was performed. By changing the F-2 dri ver-DNA allele frequency around the region, four markers were isolated from the D1Ncc1 locus. Twenty-five of 27 RDA markers were informative regarding the dot blot analysis of amplicons, hybridizing only with t ester amplicons. Dot blot analysis at a high density per unit of area made it possible to process a large number of samples. Quantitative tr ait loci can now be mapped in the rat genome by processing a large num ber of samples with RDA markers and then by isolating markers close to the loci of interest by genetically directed RDA.