Cloning Vectors | rDNA Technology | Insulin Production| PCR | Unit 2 Biotechnology 6th Semester

This extensive 6+ hour biotechnology lecture systematically covers Unit 2, beginning with cloning vectors and their essential characteristics. The instructor explains how cloning vectors like plasmids serve as carriers for genes of interest, detailing the famous pBR322 plasmid with its ampicillin and tetracycline resistance genes. The lecture thoroughly covers restriction endonucleases as molecular scissors that cut DNA at specific palindromic sequences, and DNA ligase as the molecular glue that joins DNA fragments.

The core of recombinant DNA technology is explained through the step-by-step process of isolating genes of interest, combining them with vectors, and introducing them into host cells for cloning and expression. Special attention is given to selectable markers and how they help identify successful transformants through antibiotic resistance patterns.

Practical applications are extensively covered, including the production of interferon (explaining its role as an antiviral protein and the necessity of using cDNA to avoid intron-exon complications), hepatitis B vaccine production using the HBsAg gene, and detailed insulin production methodology. The insulin section explains why A and B chains must be produced separately and then chemically combined due to bacterial limitations.

The lecture concludes with PCR (Polymerase Chain Reaction), explaining how it amplifies DNA through repeated cycles of denaturation, annealing, and synthesis, potentially creating millions of copies from a single DNA template. Applications in forensics, medical diagnosis, and research are thoroughly discussed.