Biotechnology 5th Sem Notes Free PDF Kashmir University Study Material Pdf JK crown

Genetic engineering primarily involves the manipulation ofgenetic material (DNA) to achieve the desired goal in a pre-determined way. Some other terms are also in common use todescribe genetic engineering.

 Genemanipulation

 Recombinant DNA (rDNA)technology

 Gene cloning (molecularcloning)

 Geneticmodifications

 New genetics

A clone is an identical copy.


This term originally applied to cells ofa single type, isolated and allowed to reproduce to create apopulation of identical cells. DNA cloning involves separating aspecific gene or DNA segment from a larger chromosome,attaching it to a small molecule of carrier DNA, and thenreplicating this modified DNA thousands or millions of timesthrough both an increase in cell number and thecreation ofmultiple copies of the cloned DNA in each cell. The result isselective amplification of a particular gene or DNAsegment.

MOLECULAR CLONING

The basic procedure of molecular cloning involves a series of steps.

1. Cutting DNA at precise locations. Sequence-specificendonucleases (restriction endonucleases) provide thenecessary molecularscissors.

2. SelectingasmallmoleculeofDNAcapableofself-

replication.TheseDNAsarecalled cloning vectors (a vector is a delivery agent). They are typically plasmids or viral DNAs.

3. Joining two DNA fragments covalently. The enzyme DNA ligase links the cloning vector and DNA to be cloned. Composite DNA molecules comprising covalently linked segments from two or more sources are called

recombinantDNAs.