Chromosome Walking

Chromosome walking is a method that is used to clone large segments DNA and to localize genes with a possible DNA region. It involves the sequential isolation of gene clones by copying and mapping overlapping sequences of DNA. This eventually clones long stretches of DNA sequence. You must know the length of a certain DNA sequence within the region you seek to exam. Once you know this, you can make a probe to the DNA sequence. Utilizing a genomic library that can easily be generated through partial digestion of genomic DNA with restriction enzymes, you can isolate overlapping fragments to your probe, and slowly ‘walk’ the entire length of the DNA sequence. This is similar to a staircase, where a small portion of the lower step if found under the higher step.