Deletion mapping of the lambda REX gene.

Deletion mapping has been used to order 12 lambda rex(-) mutants. Correlation of recombination data with physically-determined positions of deletion end-points (Szybalski 1971; Blattneret al. 1972) suggests that the left-most rex(-) mutation, rex209, is located about 260-300 nucleotide pairs from the p(L) mutation sex1 and about 475 nucleotide pairs from the left end-point of the region of nonhomology with lambdaimm434.