Previously published in Examiner,
Part 5 of the Forensic DNA series
DNA testing is more complicated than what most people think. There is no one test that will accomplish all that is necessary to extrapolate what we need from a genetic sample. Of course the major DNA analysis will do just that. It requires the complete DNA genome or profile. However, this DNA test is not always possible when forensic investigators only have limited DNA found at the crime scene to work with. There are several types of biological (genetic) DNA tests that will analysis evidence at a crime scene or analysis a person’s general health.
Types of DNA testing currently available
Restriction Fragment Length Polymorphism (RFLP)
Restriction Fragment Length Polymorphism (RFLP) was one of the first DNA applications, but it is not used much now because it requires large DNA samples and it breaks down if certain factors are present such as mold or dirt. RFLP requires long sequences which includes an enzyme called a restriction endonuclease.
Polymerase chain reaction PCR Analysis
PCR Analysis facilitates the capacity to make millions of DNA copies from a single biological sample. This type of analysis enables the forensic scientist to examine small data such as a few skin cells. It also lessens the chances of contamination of the sample, but it requires very meticulous work.
Short tandem repeat (STR) technology
Short tandem repeat (STR) technology analyzes all 13 Loci (regions )for DNA testing and is the technology used by the FBI databases at the local, state, and federal level. Short tandem repeat (STR) technology for DNA profiles from convicted offenders, unsolved crime scene evidence, and missing persons are recorded in these databases. The chances are a billion to one that any two people will have the same 13 DNA loci (regions) sequencing patterns (also known as a profile).
To be continued
Pro-ADN Diagnostic is Montreal’s Major DNA Testing Center
3885 Industriel Blvd.
Laval, QC H7L 4S3
T: (450) 663-6724 ext. 247
F: (450) 663-4428