Question

What are the various ways by which the desired genes can be transferred?

Answer 1

Desired genes can be transferred into host cells by two main ways.

Indirect method: uses vectors such as 

1. Plasmids (pBR322), 
2. Ti plasmid of Agrobacterium tumefaciens (natural genetic engineer in dicot plants), 
3. Retroviruses (for animal cells). 

Direct method: uses no vector, such as

1. Electroporation, where temporary pores are formed in membrane. 
2. Microinjection, where DNA is injected into nucleus with micropipette. 
3. Biolistic gene gun, where gold or tungsten particles coated with DNA are fired into cells. 

The choice depends on the host organism.