Partial digest libraries

Figure 5. Schematic illustration of partial directionality of jumping in common cutter partial digest libraries. Probe 1 adjacent to the left recleavage site only detects jumping clones 1 and 2, corresponding to jumps to the left. Probe 2 similarly only detects clones 3 and 4, corresponding to jumps to the right, while Probe 3 will detect clones corresponding to jumps in both directions (clones 2 and 3).

While partial digest libraries constructed with commonly cutting enzymes will allow entry with most available probes, this is clearly not the case with rare cutter (complete or partial)... 

The construction of a prokaryotic gene library can be achieved by a technique called shotgun cloning (Fig. 24.4). This involves the purification and partial digestion of the genomic (chromosomal) DNA... 

The probability that a sequence of interest is present in a library can be calculated as shown in Table 10.1. The optimal digestion of the target (e.g., partial digest with SamSA) to obtain maximum randomness of cloning is achieved when the most abundant insert size equals the vector capacity (Seed et al., 1982). A problem which may frequently occur is the change of representation of clones in the libraries during amplification. Some clones may be lost or become under-represented just because they reproduce slightly less rapidly. Independent libraries may then have to be screened. False positives also occur often, even if utmost care is taken to prevent contamination. 

Chromosome jumping has shown itself to be a powerful technique, especially useful in the analysis of mammalian (human and mouse) genomes. Both partial digest and rare cutter libraries have been used quite extensively and (in most cases) successfully... 

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