ABSTRACT
Chromosome walking involves the localization of gene families within a chromosome domain through the use of overlapping clones. The principle of chromosome walking initially involves the selection of an identified gene from the library, and subcloning of its end segment. Chromosome walking through small steps, through cosmid or bacteriophage, is time-consuming and laborious. In higher organisms, specially in plants, because of the heavy amount of repetitive sequences present in borders permitting crossover, it is rather difficult to map the genes following chromosome walking. The method of chromosome jumping, involves selection of the length of the hop depending on the distance to be covered; circularization by ligation of two ends of linear deoxyribonucleic acid (DNA); digestion through restriction enzymes and cloning of small DNA fragments representing junctions, the clones serving as the jumping library. Linking libraries are easier to construct and would contain very large DNA fragments as genomic inserts.
