Properties of A Good Vector

 A good vector must have the following properties:-

• The vector should be easy to isolate and purify.
• It should be easily introduced into the host cells,transformation of the host with the vector should be easy.
• The vector should have suitable marker genes that allow easy detection and selection of the transformed host cells.
• When the object is gene transfer, it should have the ability to integrate either itself the DNA insert it carries into the genome of the host cell.
• It should be able to replicate autonomously.
• A vector should be ideally less than 10 kb in size because larger DNA molecules are broken during purification procedure.
• When expression of the DNA insert is desired, the vector should contain at least suitable control elements. e.g., promoter, operator and ribosome binding sites; several other features may be also important.
• A vector should contain unique target sites for as may restriction enzyme as possible into which the DNA insert can be integrated without disrupting an essential function. 
• The cells transformed with such vector molecules that contain the DNA insert should be identifiable or selectable from those transformed by the DNA molecules only.