CONSTRUCTION AND ANALYSIS OF PST-I DNA LIBRARY FOR RFLP MAPPING OF THE RYE (SECALE-CEREALE L) GENOME

Pst I, a methylation-sensitive restriction enzyme, was used for produc ing a library of rye genome DNA rich in low-copy sequences, and intend ed as probes for genetic mapping. Dot-hybridization and Southern blot analysis showed that 43.6% of the library is represented by low-copy D NA sequences. To locate these sequences on chromosomes and determine t he degree of their repetitiveness, II clones were hybridized with DNA of nullitetrasomic lines of Chinese Spring wheat, wheat-rye addition l ines, and barley cleaved by Hind III, EcoR I, EcoR V, Dro I, and BamH I, restriction enzymes. Each of the rye DNA clones studied hybridized with wheat and barley DNA, suggesting that low-copy Pst I clones of ry e correspond to the evolutionary conservative DNA fraction in cereals.