Forensics Notes

Human Genome Project
- 13-year project coordinated by the U.S. Department of Energy and the National Institutes of Health (1990-2003)
- identification of about 20,000-25,000 genes in the human DNA and store the information in databases.
- identification works through the examination of DNA. Forensic scientist scans 13 DNA regions of an individual and uses the information to create a DNA profile.
- Only one-tenth of a single percent of DNA differs from one person to the next.
- The use of samples from blood, bone, hair and other body tissues and products can generate DNA.



Technologies used in forensic investigations
- RFLP – Restriction Fragment Length Polymorphism
o Technique for analyzing DNA fragments that result from digesting DNA samples with an enzyme, which cuts DNA at a specific sequence pattern called a restriction endonuclease recognition site. The absence or presence of this “site” in a DNA sample generate a variable lengths of DNA fragments. This technique isn’t used as much because it requires large amounts of DNA and it does not work well with samples degraded by environmental factors.
- PCR Analysis – Polymerase Chain Reaction
o This analysis is used to create millions of copies of DNA from a biological sample. It allows DNA analysis on biological samples as small as a few skin cells.
- STR Analysis – Short tandem repreat
o Used to evaluate specific regions within nuclear DNA. “Variability in STR regions can be used to distinguish one DNA profile from another.” The FBI uses 13 specific STR regions for a software program that operates local, state, and national databases of DNA profile from convicted offenders, unsolved crime scene evidence and mission persons called CODIS (combine DNA index system).
- mtDNA - Mitochondrial DNA Analysis
o It examine the DNA from Samples that cannot be analyzed by RFLP or STR. mtDNA analysis uses DNA extracted from another cellular organelle called a mitochondrion.
- Y-Chromosome Analysis
o Useful for tacing relationship among males or for analyzing biological evidence involving multiple male contributors.



DNA forensic Databases – CODIS
- Combine DNA Index System – a combination of computer and DNA technology, which creates a tool for fighting violent crimes.
- CODIS enables an exchange and comparing of DNA profiles electronically, thereby linking crimes to each other and to convicted offenders.
- Began in 1990 serving 14 states and local laboratories.
- Three levels – local, state and national. NDIS level is the highest level, comparing and exchanging DNA profiles on a national level. SDIS (state level) allows laboratories within states to exchange DNA profiles.
- Today CODIS Is installed in more than 100 laboratories!
- NDIS contains more than 210,000 profiles from 24 states.
- CODIS uses biological evidence which is recovered from crime scene and separates them into 2 indexes:
o Forensic Index – contains DNA profiles from crime scene evidence
o Offender Index – contains DNA profiles of individuals convicted of violent crimes.
- By 1999, CODIS has produced over 600 hits assisting in more than 1,100 investigations.


a good book which deals with forensisis called FORENSIC DENTAL EVIDENCE by C. Michael Bowers.


"This compact text is authored by a well respected forensic odontologist, and is aimed at anyone who is involved in utilising dental evidence, including the police, forensic investigators, dentists and pathologists."


I found a video which explains what a Forensic Investigator does See Video

Source:
http://www.ornl.gov/sci/techresources/Human_Genome/home.shtml
http://www.dur.ac.uk/p.j.johnson/eu.html
http://www.tncrimlaw.com/forensic/
http://www.fbi.gov/hq/lab/codis/index1.htm
http://www.forensicmed.co.uk/books_10.htm