The successful linkage of the antibiotic resistance gene with the plasmid vector was facilitated by which enzyme?

DNA ligase

The correct answer is Option (1)- DNA ligase

In 1972, Stanley Cohen and Herbert Boyer achieved the construction of the first recombinant DNA by linking a gene encoding antibiotic resistance with a native plasmid of Salmonella typhimurium. This breakthrough involved isolating the antibiotic resistance gene by excising a segment of DNA from a plasmid responsible for conferring antibiotic resistance. The process of cutting DNA at specific locations became possible with the discovery of "restriction enzymes," often referred to as "molecular scissors." After cutting the DNA, they joined the excised segment with the plasmid DNA. These modified plasmid DNA acted as vectors, facilitating the transfer of the linked DNA segment. This landmark achievement laid the foundation for modern genetic engineering and biotechnology.

Aplasmid can be used as vector to deliver an alien piece of DNA into the host organism. The linking of antibiotic resistance gene with the plasmid vector became possible with the enzyme DNA ligase, which acts on cut DNA molecules and joins their ends. This makes a new combination of circular autonomously replicating DNA created in vitro and is known as recombinant DNA.