The traditional method for creating recombinant DNA typically involves the use of plasmids in the host bacteria. The plasmid contains a genetic sequence corresponding to the recognition site of a restriction endonuclease, such as EcoR1. After foreign DNA fragments, which have also been cut with the same restriction endonuclease, have been inserted into host cell, the restriction endonuclease gene is expressed by applying heat, or by introducing a biomolecule, such as arabinose. Upon expression, the enzyme will cleave the plasmid at its corresponding recognition site creating sticky ends on the plasmid. Ligases then joins the sticky ends to the corresponding sticky ends of the foreign DNA fragments creating a recombinant DNA plasmid.
Advances in genetic engineering have made the modification of genes in microbes quite efficient allowing constructs to be made in about a weeks worth of time. It has also made it possible to modify the organism's genome itself. Specifically, use of the genes from the bacteriophage lambda are used in recombination. This mechanism, known as recombineering, utilizes the three proteins Exo, Beta, and Gam, which are created by the genes exo, bet, and gam respectively. Exo is a double stranded DNA exonuclease with 5’ to 3’ activity. It cuts the double stranded DNA leaving 3’ overhangs. Beta is a protein that binds to single stranded DNA and assists homologous recombination by promoting annealing between the homology regions of the inserted DNA and the chromosomal DNA. Gam functions to protect the DNA insert from being destroyed by native nucleases within the cell.
Other articles related to "method":
... Starting from the argument that a historical universal scientific method does not exist, Feyerabend argues that science does not deserve its privileged status in western society ... Since scientific points of view do not arise from using a universal method which guarantees high quality conclusions, he thought that there is no justification for valuing ... state are separated in a modern secular society ( Against Method (3rd ed.) ...
Famous quotes containing the word method:
“... the one lesson in the ultimate triumph of any great actress has been to enforce the fact that a method all technique or a method all throes, is either one or the other inadequate, and often likely to work out in close proximity to the ludicrous.”
—Mrs. Leslie Carter (18621937)
“Women stand related to beautiful nature around us, and the enamoured youth mixes their form with moon and stars, with woods and waters, and the pomp of summer. They heal us of awkwardness by their words and looks. We observe their intellectual influence on the most serious student. They refine and clear his mind: teach him to put a pleasing method into what is dry and difficult.”
—Ralph Waldo Emerson (18031882)
“I have a new method of poetry. All you got to do is look over your notebooks ... or lay down on a couch, and think of anything that comes into your head, especially the miseries.... Then arrange in lines of two, three or four words each, dont bother about sentences, in sections of two, three or four lines each.”
—Allen Ginsberg (b. 1926)