DNA IN CRIMINAL INVESTIGATIONS

DNA in Criminal Investigations

Introduction

Polymorphism (RFLP), Polymerase chain reaction (PCR), Short tandem repeat (STR), Mitochondrial DNA analysis (mtDNA), Y-Chromosome Analysis. Criminal DNA testing is very useful and credible to the investigating officers, attorneys, police etc as it relays valuable information. Over the years, Criminal DNA testing has become a standard in every country in order to certify the human beings identity. As research on the maps of chromosomes continues and new discoveries are made, the level of characterization of the human genome is reaching dramatic new levels. Forensic Analytical uses the most technologically advanced methods of criminal DNA testing, such as PCR-based DNA typing and short tandem repeats (STRs).

Main Body

PFGE of whole chromosomal DNA. This type of DNA typing method is known as the gold standard. For PFGE, bacterial isolates grown either in broth or on solid media are combined with molten agarose and poured into small molds. The results are agarose plugs containing the whole bacteria. The embedded bacteria are then subjected to in situ detergent-enzyme lysis and digestion with an infrequently cutting restriction enzyme. The bacterial plugs that are digested then goes in to another step that is they are inserted in to an agarose gel. After this a few more steps are conducted in order to carry out the test.

Old Methods

The old methods of DNA typing were through RLFP, finger prints, PCR etc. The reasons why these methods were abolished was because these methods delayed the results and the results were not very much accurate. There was always a 2% chance that the output from these methods would be in accurate and this is the reason why the method was brought down to STR's DNA typing method. There are a number of systems that are being used in different countries, and the problem ...