MAPS FROM 2 INTERSPECIFIC BACKCROSS DNA PANELS AVAILABLE AS A COMMUNITY GENETIC-MAPPING RESOURCE

We established two mouse interspecific backcross DNA panels, one conta ining 94 N2 animals from the cross (C57BL/6J X Mus spretus)F-1, X C57B L/6J, and another from 94 N2 animals from the reciprocal backcross (C5 7BL/6J X SPRET/Ei)F-1 x SPRET/Ei. We prepared large quantities of DNA from most tissues of each animal to create a community resource of int erspecific backcross DNA for use by laboratories interested in mapping loci in the mouse. Initial characterization of the genetic maps of bo th panels has been completed. We used MIT SSLP markers, proviral loci, and several other sequence-defined genes to anchor our maps to other published maps. The BSB panel map (from the backcross to C57BL/6J) con tains 215 loci and is anchored by 45 SSLP and 32 gene sequence loci. T he BSS panel map (from the backcross to SPRET/Ei) contains 451 loci an d is anchored by 49 SSLP loci, 43 proviral loci, and 60 gene sequence loci. To obtain a high density of markers, we used motif-primed PCR to ''fingerprint'' the panel DNAs. We constructed two maps, each represe nting one of the two panels. All new loci can be located with a high d egree of certainty on the maps at current marker density. Segregation patterns in these data reveal several examples of transmission ratio d istortion and permit analysis of the distribution of crossovers on ind ividual chromosomes.