This animation shows how a gene can be cloned into a plasmid vector by cutting the DNA molecule using restriction enzymes or restriction endonucleases (in this case EcoRI), and then pasting the new piece of DNA into the plasmid at the sticky ends using an enzyme called ligase. This new recombinant DNA molecule can be cloned by being grown in bacteria cells. This is known as recombinant DNA technology.

Duration: 1 minutes 12 seconds

A common technique in genetic engineering is to insert a new gene into a loop of bacterial DNA called a plasmid. "The molecular tool used to cut DNA is a restriction enzyme such as EcoR1. The enzyme has a precise shape that allows it to run along the groove of the double helix, scanning for the base letter sequence G A A T T C EcoR1 then cuts the plasmid at this specific point......allowing a new piece of DNA to be inserted. When it cuts, EcoR1 leaves a sticky end, which helps the new gene to attach. The joins are then stitched together by another enzyme called DNA ligase." The genetically engineered bacteria is then grown in a culture medium. Very quickly, large numbers of the bacteria can be produced, each with a copy of the inserted gene. The bacteria duly manufacture whatever protein the gene codes for, and so the desired product is produced.