Question

1. Generally a plasmid cloning vector will contain three elements. What are these three elements?

2. What is the purpose to have a resistant gene (an ampicillin-resistant gene in this case) on the cloning vector?

Answer 1

The ideal plasmid cloning vector must have small size, high copy number , own origin of replication , restriction sites for many restriction enzymes and selectable marker.

1. polylinker site.

2. selectable marker

3. antibiotic resistance gene.

---> Genetic marker is a gene that allow the selection of transformed from non-transformed cell and recombinant containing transformed cell from non-recombinant containing transformed cell. Marker genes belongs to two broad categories ; selectable markers and screenable markers . A selectable marker gene encodes a product that allows the growth of one type of cells under specific conditions that kills or restrict the growth of other types of cells . A screenable marker gene , also called reporter gene , gives a product that can be detected using a simple and often quantitative assay.