Chromosome jumping is the technique whereby one begins with a piece of DNA from one area of a chromosome, and obtains clones from nearby areas without cloning everything in between (as in chromosome walking). One round of jumping yields the new clones at the distances of several tens of kb away from the beginning point. In practice, this method is used when classical genetics proves that a known piece of DNA is located on the chromosome close to the gene you would like to clone (like a human disease gene). By cloning the fragments some distance away in both the directions from the known fragment, one might attain 
(1) fragments further from the required gene (which are discarded); 
(2) the fragments are even more closely linked to the required gene (in which case one goes for another round of jumping); or 
(3) fragments from within required gene - the optimal result.