Forensic DNA testing

At this point in time, at the beginning of the 21st century, forensic DNA testing has moved away from RFLP test-... 

Gel electrophoresis has been applied to soil DNA and RNA extracts using procedures similar to those used in DNA testing for forensic analysis. CE has also been applied to the analysis of ionic species extracted from soil. While these processes show promise for the elucidation of valuable information about soil, neither is used for common, routine soil analysis [12-14],... 

More recently, the forensic application of DNA testing has dramatically enhanced the ability to determine the source of a blood sample. Two procedures are in forensic use restriction fragment length polymorphism (RFLP) and polymerase chain reaction (PCR). 

Forensic scientists examine evidence from crime scenes in an effort to solve crimes. This scientist is removing a piece of blood-stained material gathered at a crime scene for DNA testing. 

AGTAGTAGTAGTAGT... ), etc. Due to polymerase slip (a.k.a. polymerase chatter), during DNA replication there is a slight chance these repeat sequences may become altered copies of the repeat unit can be created or removed. Consequently, the exact number of repeat units may differ between unrelated individuals. Considering all the known microsatellite markers, no two individuals are identical. This is the basis for forensic DNA identification and for testing of familial relationships (e.g., paternity testing). 

Real-World Reading Link DNA testing is becoming more routine in medicine, forensic science, genealogy, and identification of victims in disasters. Modern techniques have made it possible to get a useful DNA sample from surprising sources, such as a strand of hair or dried saliva on a postage stamp. 

The major application of CE in forensic biology is in the detection and analysis of short tandem repeats (STRs). STR markers are preferred because of the powerful statistical result that is possible with these markers and the large databases that exist for convicted offenders profiles. Other related applications include the analysis of haploid markers in the Y chromosome and in mitochondrial DNA (mtDNA). Nonhuman DNA testing can also be performed depending on the circumstances of the case. The techniques involved include genotyping, DNA sequencing, and mutation detection. 

The dermal material in the hair root where the hair shaft is produced is an example of such tissue. As the shaft is created and subsequently keratinized the mitochondrial particles are trapped in the shaft and persist in the hair. The mtDNA thus presents a more promising target for DNA testing and indeed the exploitation of this feature of hair has become an important part of forensic hair analysis. 

Forensic Genetics. Forensic genetics is the use of human genetics in criminal or paternity cases. For example, DNA testing on blood, saliva, or other tissue can be used to determine the source of evidence, such as blood stains or semen, left at a crime scene. Forensic DNA analysis is also used to determine paternity and other kinship. Finally, with the increasing use of forensic genetics since the 1990 s, some incarcerated prisoners have been released after it was clearly determined that they could not possibly have been guilty of crimes they were convicted of, as DNA evidence eliminated them from suspicion. 

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