The process of putting a gene into a vector is called molecular cloning or gene cloning. Most vectors are based on plasmids, which are small circular sequences of DNA that occur naturally within bacteria. Plasmid vectors can accept a few genes’ worth of DNA.o introduce foreign DNA into a circular vector, scientists carry out a three-step process: 1  Cutting out the gene. 2  Scientists first remove their gene of interest from the DNA sequences on either side of it.