(a) Mention the role of vectors in recombinant DNA technology. Given any two examples.
(b) With the help of diagrammatic representation only, show the steps of recombinant DNA technology.
Answer The cloning vectors are DNA molecules that can carry a foreign DNA segment and replicate inside the host cell. These are plasmids, cosmids, phagemids, yeast artificial
chromosome (YAC), bacterial artificial chromosome (BAC), transposons and virus.
Cloning vector carry rDNA and they generally have high copy number, they can produce multiple number of required gene. Vectors help in easy linking of foreign DNA and in selection of recombinants from non recombinants. The entire procedure of gene cloning or recombinant DNA technology may be classified into the following six steps
for the convenience in description and on the basis of the chief activity performed.
(i) Production and isolation of the DNA fragments to be cloned.
(ii) Insertion of the isolated gene in a suitable vector to obtain recombinant DNA. Introduction of the recombinant DNA into a suitable organism/cell (usually E.coli) called host (transformation).
(iv) Selection of the transformed host cells, and identification of the clone containing the desired gene/DNA fragment.
(v) Multiplication/expression of the introduced gene in the host.
(b) (b) Diagram showing various steps of recombinant DNA technology is given below:
