Genetic Engineering and Recombinant DNA Technology is a set of techniques that allows scientists to identify and isolate genes from any organisms to multiply.*An example would be the isolation, extraction and grafting of human gene for insulin production in bacteria of Escherichia coli.*These bacteria containing the human gene, multiply when cultured in the lab, producing insulin, which is currently done on a large scale.

bacterial plasmid

bacteria, especially Escherichia coli, is one of the main biological materials used in recombinant DNA technology.*This is due to several factors:*

- fast life cycle in relation to higher organisms.*
- the cultivation of a large number of individuals in a small space*
- has fewer genes compared to higher organisms*
- cell division by binary fission.*
In addition to chromosomal DNA, the bacterial cell contains small circular DNA molecules called plasmids.*This has an existence independent of the chromosome, however, its duplication is synchronized with the bacteria, thus ensuring its transmission to daughter bacteria.*

genetic engineering genes "strangers" bacteria can be incorporated into their plasmids, and thus these bacteria start to produce the proteins that these genes encode.*
Some plasmids have genes for the synthesis of enzymes that destroy an antibiotic before it is bad bacteria.*

Plasmids carrying genes that confer resistance to drugs are called plasmids R (R Resistance).*They also have genes that allow their passage from one bacterium to another (RTF or Resistance Transfer Factor).*

When two or more types of R plasmids are present in the same bacterium, the genes of one of them can move to the other.*This mechanism gives rise to very complex R plasmids, carry several genes for resistance to different antibiotics.*

This property of antibiotic resistance genes to move from one DNA molecule to another has led scientists to classify the transposons or jumping genes.


Molecular cloning*
plasmids Once prepared, the task is to insert them into bacterial cells.*Plasmids and bacterial cells are placed in contact with one another.*However, only a few bacteria can absorb the new plasmid, is necessary now, select the population of bacteria that really incorporated the plasmid with the new gene.*
plasmids Some bacteria naturally carry genes that confer resistance to certain antibiotics.*The researchers choose to recombinant DNA plasmids that already have the gene for antibiotic resistance.*Then, these plasmids are opened, and the genes to be grafted are embedded.*These plasmids are placed in contact with bacteria sensitive to antibiotics, and to incorporate some of these.*To select the bacteria that have earned the new plasmid simply add the antibiotic to the culture medium. All the bacteria without the plasmid die, because they are not resistant to the antibiotic, leaving only those with the plasmid with the gene for antibiotic resistance. These bacteria thrive and all the resulting clone will contain the plasmid with the new gene.