MAPPING OF MOUSE INTRACISTERNAL A-PARTICLE PROVIRAL MARKERS IN AN INTERSPECIFIC BACKCROSS

We present a linkage map of intracisternal A-particle (IAP) proviral l oci. The IAP family consists of 2000 endogenous proviral elements that are widely dispersed in the mouse genome. The map was constructed by using an interspecific backcross and markers defined by oligonucleotid e probes specific for subclasses of expressed IAP elements. In genomic DNA from C57BL/6J mouse, these probes each detected from 12 to 44 Hin dIII restriction fragments that represent junctions between proviral a nd 5'-flanking DNA. The fragments have characteristic strain distribut ion patterns (SDPs) that are particularly polymorphic in the DNAs of C 57BL/6J and Mus spretus mice used for the backcross. IAP loci were pla ced on.the map by comparison of their distribution patterns with those of known genetic markers in the backcross. The map includes 51 IAP lo ci that have not been previously mapped and 23 IAP proviruses that had been previously mapped in recombinant inbred (RI) strains. Comparable map positions were obtained with the IAP markers in the interspecific backcross and the RI strains. The mapped IAP loci were widely dispers ed on the X Chromosome (Chr) and all of the autosomes except Chrs 9 an d 19, providing useful genetic markers for linkage studies.