DNA identification

Mihalov JJ, Marderosian AD, Pierce JC, et al (2000) DNA identification of commercial ginseng samples. J Agile Food Chem 48 3744-3752... 

Olsen R, Molander P, Ovrebo S, et al. Reaction of glyoxal with 2 -deoxyguanos-ine, 2 -deoxyadenosine, 2 -deoxycytidine, cytidine, thymidine, and calf thymus DNA identification of DNA adducts. Chem Res Toxicol. 2005 18(4) 730-739. 

Figure 10.7. Restriction fragment length polymorphism for DNA identification.

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). 

Capillary electrophoresis (CE) has been assuming an increasingly important role in forensic DNA identification. In the World Trade Center disaster, the materials collected at the site were trucked and barged to the Fresh Kills Landfill in the center of Staten Island. Human remains were then segregated and used to obtain DNA evidence. Capillary electrophoresis was often the tool of choice in the identification process. CE is particularly useful when only small amounts of sample are available and when samples may have degraded with time. CE has been used to identify DNA in bone, blood, semen, saliva, and hair. 

In diagnostic clinical medicine, DNA identification has been applied to investigations of patient tissue specimens obtained during biopsies or autopsies. Because of imaginative adaptations of DNA extraction techniques, the DNA contained in slides and preserved tissue specimens can now be investigated for evidence of infectious or genetic diseases. For example, in situ DNA hybridization is an ultrasensitive technique in which specific DNA probes are applied directly to tissue embedded in paraffin. (Paraffin-embedded tissue specimens are used in microscopic studies. Such slides can be stored... 

The above described PCR can only amplify the number of copies of a DNA molecules in the sample. In order to know what DNA or specific DNA sequence it is, however, one has to perform additional analyses, such as using gel electrophoresis or DNA sequencing method to find the answer. A direct DNA identification method, called the real-time PCR, combining both the PCR with fluorescent detection, is most useful in this regard. 

Side note Lab-on-a-chip, Enzyme-catalyzed polymerization of nucleon is a key step in DNA identification. The microfluidic device shown in 1 ure SN7.1 is used to identify DNA strands. It was developed by Profe Mark Burns s group at the University of Michigan. 

Walker JA, Hughes DA, Anders BA, Shewale J, Sinha SK, Batzer MA (2003). Quantitative intra-short interspersed element PCR for species-specific DNA identification. Anal. Bio-chem.. May 15, 316(2) 259-269. 

Figure A13.1 DNA identification. Variations in our DNA lead to different sizes of fragment when it is cut up with restriction enzymes. This is the basis of the DNA identification now so useful for forensic identification.

Brenner, C.H. and Weir, B.S., Issues and strategies in the DNA identification of World Trade Center victims. Theor. Popul. Biol., 63, 173, 2003. 

Department of Defense DNA Registry Armed Forces DNA Identification Laboratory Armed Forces Institute of Pathology... 

In response to arguments about the validity of courtroom use of DNA identification, the National Academy of Sciences conducted a review. They concluded that there is no reason to question the rehahihty of properly analyzed DNA evidence. 

A technology that could read the DNA from a sample and rapidly and accurately identify the organisms therein would address this problem. Using the mechanisms discussed heretofore in this chapter, a system has been developed with these capabilities. Currently, polymerase chain reaction (PCR) amplification followed by fluorescent analysis is the most common method of DNA identification. PCR is a well-understood and reliable laboratory process, but it is highly susceptible to contamination, is labor intensive, and requires a skilled operator and specialized equipment. It is best suited to use within a laboratory... 

---