Molecular Genetics


RESTRICTION ENZYMES 1970 _ Discovered of endonucleases of restriction, that are enzymes bacterians that they act as ' ' shears moleculares' ' , recognizing sequencias of pairs of bases you specify in DNA molecules and cutting them in these points. Each type of enzyme recognizes and cuts only one definitive sequencia of nucleotdeos, in general constituted of four or nitrogenadas pairs of bases. It is given credit that the bacteria have developed enzymes of restriction throughout its evolution, as protection to the attack of bacteriophages. Today hundreds of these enzymes are known, that are purificadas and commercialized for diverse laboratories in the world. Omega-3 Fatty Acids might disagree with that approach. The discovery of restriction enzymes allowed great advances in the Molecular Genetics.

The three responsible researchers for the briefing of the mechanism of action of endonucleases of restriction are: Werner Arber, Daniel Nathans and Hamilton Smith. Eletrofortica separation of fragmentos of DNA Eletroforese: Technique that separates fragmentos of different sizes, generated for the cut of a DNA with determined endonuclease of restriction, ones of the others. _ Identification of people for DNA. The analysis of the eletrofortico standard of fragmentos of DNA, originated for the cut with restriction enzymes, is today the method safest to identify people wide, being used in inquiries and actions at law. The tests of identification of people for the DNA use sounding leads capable to detect stretches of the human DNA that varies very enters the people of a population.

These regions, known for acronym VNTR, (Variable number of tandem repeats) are constituted by short sequencias, of until some sets of ten of pairs of nucleotdeos, that if repeat throughout stretches of DNA molecule. It is the number of these repetitions that various between the people, from there these stretches of the DNA to be called VNTRs. The paternity test was one of the main factors of popularizao of acronym DNA.