Introduction of Recombinant DNA Technology

   

        Recombinant DNA technology has been developed with DNA cloning techniques for locating, isolating, and studying small fragments from the large chromosome. The basic things need to understand DNA cloning is to make identical copies by involving gene separation, DNA fragment attachment and replicating the modified DNA. The process composed of several steps. Cutting the DNA at the specific locations with a restriction endonuclease. Then DNA fragment is connected to the vector with DNA ligase. The vector might be plasmid, bacteriophages, bacterial artificial chromosomes (BAC) depend on the purpose that clones in different sizes. However, the important things from the vectors are origin replication to multiply in the bacterial hosts and selectable marker-trait for determining the cell containing the recombinant vector. The recombinant DNA transformed into the host cell for replication. Lastly, selecting the host cell contains the recombinant DNA. Before isolating the DNA fragment, we sometimes need to look at the DNA library and the sequence of the fragment. The DNA libraries include the fragment that represents the genome of the organism, while the specific fragment can be amplified with polymerase chain reaction (PCR). The expressed genes also can be used by changing the mRNA to the complementary DNA (cDNA) with transcriptase enzyme. To detect the particular gene of the nucleic acid, the DNA hybridization method can be used by using radioactive to label DNA or RNA fragment, probe and cDNA to detect DNA fragment. Related to DNA libraries, PCR, and hybridization, the technology has been developed the DNA microarrays that can screen sequences quickly. To implement the method, the cloned genes can be expressed to produce products (protein), or altered to produce different proteins from the native forms. The concepts lead to open the knowledge and generate new methods using yeast as eukaryotic host and yeast artificial chromosomes. Bacterial plant parasite like Agrobacterium used to clone recombinant DNA into plants, while human gene therapy can be cloned in animal cells by maintaining the conditions.