Resolution Gap Difference in Genomes of Different Sizes -In preparing genetic RFLP maps, 1 cM (centiMorgan) is often considered to be the limit of resolution achievable without examining a very large population. At the molecular level, this limit of resolution means different physical distances in organisms, with genomes of different sizes.

This gap, therefore needs to be bridged, if a gene of interest is to be approached from a linked RFLP locus, that has been mapped. Bridging of this gap has become possible due to development of techniques like pulse field gel electrophoresis (PFGE) and cloning in yeast artificial chromosome (YAC) vectors, which will enable handling of large pieces of DNA.

Similarly jumping and linking libraries can be prepared, so that chromosome walking need not be followed throughout the genome to identify, locate and isolate a gene of interest.