Vectors in biotechnology process is a carrier for the genetic material to transfer to the desired organism's genome. Vectors are also used for making copies or clones. Origin of replication in a vector enable replication of the vector and vector supporting higher copy number is preferred. Vector having a selectable marker is preferred as it will help in identifying the transformant from non-transformants.

One of the process to detect the transformants is by adding sequence of beta-galactocidase which when expressed produces blue colour due to presence of chromogenic substance in non-recombinants and no colour in recombinants/transformants.