MAPPING REPLICATION ORIGINS BY NEUTRAL NEUTRAL 2-DIMENSIONAL GEL-ELECTROPHORESIS/

Neutral/neutral two-dimensional gel electrophoresis is a sensitive phy sical mapping technique that has been successfully used to unambiguous ly identify replication initiation sites in genomes of widely varying complexity in vivo. The technique exploits the fact that restriction f ragments containing different classes of replicative intermediates (si ngle forks, initiation bubbles, or termination structures) migrate to different and characteristic positions in agarose gels. The replicatio n pattern of any region of interest can then be determined by sequenta l hybridization with appropriate radioactive probes from that region. (C) 1997 Academic Press.