MANNING TRANSLOCATION BREAKPOINTS BY ORTHOGONAL FIELD AGAROSE-GEL ELECTROPHORESIS

Orthogonal field agarose-gel electrophoresis (OFAGE) of chromosomes fr om translocation-bearing and normal Neurospora crassa strains was util ized, first, to recover cosmids from a translocated region, and second , to map translocation breakpoints. Surprisingly, the right breakpoint s in two independently derived, interstitial translocations, T(II --> III) AR18 and T(II --> VI)P2869, are within about 5.6 kbp of each othe r suggesting that this region of linkage group (LG) II may be fragile or otherwise subject to chromosome breakage. Mapping translocation bre akpoints through OFAGE, or other similar methods, should allow for DNA sequencing across breakpoints that are not associated with mutant phe notypes or that are not within walking distance of cloned markers.