Chromosome walking

Working from a flanking DNA marker, overlapping clones are successively identified that span a chromosomal region of interest. (See Chromosome.)

A strategy for mapping or sequencing a chromosome segment and for positional cloning. Large restriction fragment s (or BAC clones) are generated and, after probing, a single starting point is identified. New probes are synthesized complementary to sequences of the same fragment (BAC clone) that are adjacent to the starting point, and these are then used to identify different restriction fragments (BAC clones) overlapping the one selected as the starting point. The procedure is used repetitively, working away from the starting point.