Isolation of High Molecular Weight DNA Suitable for the Construction of Genomic Libraries

Recent advances in molecular biology have made it possible to construct complete gene libraries for any organism that uses DNA as its carrier of genetic information. A gene library should contain a large number of cloned DNA fragments that in total contain the entire donor genome. The construction of a genomic library first requires the isolation of DNA from the donor organism. To be of maximum use in the construction of genomic libraries, DNA isolated from the donor organism should fulfill the following criteria. First, the DNA must represent all sequences in the genome to be cloned. Second, it must be of high molecular weight. Third, no contaminants must taint the DNA so that its use as a substrate for restriction endonucleases and other enzymes used in genetic engineering is uninhibited.