jimtrue.com : school : CJT2141 : 13: DNA
Posted by Jim True on April 9, 2003 7:00 AM. Last Updated October 22, 2006 9:23 PM
Disclaimer for all material noted here is at the bottom of this web page.
DNA Video:
Genlex, DNA and paternity testings.
Evidence test: blood
DNA Testing:
We all have it, different in everyone, except in identical twins.
Nuclear DNA, double-helix. Polymer, definitely has certain groups to it. Unzip the double-helix, cut off part of it and then replicate that part and do the analysis on the replicated sample. PCR. Running different probes on sample that we copy. PCR, Polymerase Chain Reaction.
RFLP, is like electrophoresis - 4 or 5 probes provide same electrophoresis probe, will determine. Restriction Fragment Length Polymorphisms.
4 Bases:
A
T
C
G
A-T combines
C-G combines
Base Complement, that's why you can use 1/2 the strand. T will always match with A, C match against G.
No nuclear dna in red blood cells. In white blood cells.
Mitochondrial DNA, comes from the mother. Not inside the nucleus, more of it. Sister's mitochondrial DNA is same as yours. Lost people, identifying remains. Not the same discrimination as Nuclear DNA. Maternally inherited. Does not have the discriminating power of Nuclear DNA. 10 x more expensive than PCR or even RFLP.
PCR, can deal with small sample. Cannot individualize (though STR will allow higher discrimination because it does more probes). Thermocycler. Cheaper method. Confirmatory.
RFLP, positive individual evidence. Several probes; dealing with many strands. Time consuming, radioactivity. Contamination does not become an issue because it separates it out. Sample about the size of a dime. PCR can be a much smaller sample (epithelial, etc.)
CODIS - DNA Databank. Sex offenders, murderers, etc. in a database. Florida's run by the FDLE, but also maintained by the FBI. RFLP, STR's. Rapes no suspect, murders. Check for match in CODIS. Radiographs, against people in the system. Sample submitted which matches that you need to compare. Analyzed by individual for confirmation. Huge backlog on CODIS data.
Disclaimer: These are MY notes taken from classroom lectures while I'm in the classroom. While I'm perfectly happy to share my notes with my classmates and I know I take very good notes, you should still make every effort to attend the class and TAKE YOUR OWN NOTES. I will not transcribe everything the instructor says in the classroom, and I will NEVER post pre-exam reviews. My notes will not replace the value of actually attending class and taking your own class notes.I also cannot attest to their accuracy, other than they are what was provided in the lecture; you should not reference my notes as "expert opionion" by any means, and if you notice an error or omission, please do me the favor of e-mailing me with the correction and I will re-post my notes. End of Disclaimer.