Question

Explain the properties of a good or ideal cloning vector for rDNA technology.

Answer 1

Following characteristic properties, a cloning vector must possess in order to be used in rDNA technology:

1. A good vector should have the ability of independent replication so that as the vector replicates (through ori gene) and a large number of copies of the DNA insert will be formed.
2. The vector should be able to easily introduce into host cells.
3. A vector should have marker genes for antibiotic resistance.
4. A vector must contain a unique cleavage site in one of the marker genes for the restriction enzyme.
5. It should have at least suitable control elements like a promoter, operator, ribosomal binding sites, etc.
6. The plasmids obtained naturally do not possess all the characteristics. Hence, they are constructed by inserting a gene for antibiotic resistance. eg. pBR322, pBR320, pACYC177 are the constructed plasmids. pBR322 is mostly used in rDNA technology in plants.