pBR322 (Plasmid pBR322) class 12

Описание: pBR322 is one of the first and most widely used artificial plasmid vectors in genetic engineering. It was developed in 1977 by Bolivar and Rodriguez, and is commonly used for cloning foreign DNA in Escherichia coli.
The plasmid pBR322 is circular, double-stranded DNA with a size of about 4361 base pairs. It contains several important genetic features that make it suitable as a cloning vector.
Main Features of pBR322:
Origin of replication (ori):
Allows the plasmid to replicate independently inside the bacterial cell.
Selectable marker genes:
ampR gene → provides resistance to ampicillin
tetR gene → provides resistance to tetracycline
These markers help in identifying transformed bacteria.
Restriction sites:
pBR322 has unique restriction enzyme sites (like EcoRI, HindIII, BamHI, PstI) where foreign DNA can be inserted.
Small size:
Its small size helps in easy isolation and manipulation.
Importance of pBR322:
Used in gene cloning and recombinant DNA technology
Helps in selection and identification of recombinant cells
Commonly studied in Class 12 Biology (NCERT)
👉 If you want, I can also give this in short exam-ready points, Hindi, or with a diagram explanation.