The Construction And Preliminary Characterization Of Rat Genomic Library

Genoraic DNA library is a collection of recombinant DNA clones which contain the complete gene' s random fragments. It is called genomic library because it have complete DNA fragments of the genome, liking a data bank of all genomic sequence.The genomic DNA was extracted from a special rat's liver and partial cleavaged with a four-base cutter restriction endonuclease (Sau3AI) to get suitable size DNA fragments. We isolated the fragments between 9~23kb using sucrose density gradient centrifugation and got recombinant phages of various DNA fragments by ligating the DNA fragments with the vector DNA (lambda GEM-11), packaging ligation product in vitro and transformating competent E coli cells. Titering packaged phage on LB plates, we calculated the packaging efficiency was 10~6pfu/ugDNA and demonstrated the genomic library' s integrity. Then we selected several plaques, extracted the phage DNA and examinated the size of the inserted fragments were between 9~23kb by restriction digestion. At last we manipulated lambda phage in large scale with high infection technique and extracted genomic library's DNA and examinated the integrity of genomic library by PCR method. The PCR products' size were in accordance with anticipation by using agarose gel electrophoresis.