Which of the following is not necessary for the preparation of recombinant DNA molecules?

DNA ligases . Restriction endonucleases . DNA fragments . E.coli

E.coli

E. coli is not required for preparation of a recombinant DNA molecule rather it may be required for the expression of recombinant DNA-molecule. Restriction enzymes and DNA ligases can be used to make a stable recombinant DNA molecule with DNA fragments that has been spliced together from two different organisms. Genetic engineering or recombinant DNA technology can be accomplished only if we have the key tools, i.e., restriction enzymes, polymerase enzymes, ligases, vectors and the host organism .