Isolation of DNA (Gene) from the Donor Organism

The first step is obtaining the desired gene from its source (donor) organism. The donor's cells are first sheared, for example with a blender, and treated with a suitable detergent to break them open; the genetic material released is then isolated and purified using several techniques, and isolated DNA can even be spooled onto a glass rod to collect it.

This isolated, purified DNA is then cleaved using restriction enzymes, particularly restriction endonucleases (RE), which cut it at specific restriction sites and break it into fragments -- these fragments can end up with cohesive/sticky/staggered ends or with blunt ends, depending on the enzyme used. From among the resulting fragments, the one carrying the desired gene is identified and selected for cloning; from this point on it is called the foreign DNA or **passen …