The Current Effects of DNA in forensic Criminology in the 21st Century By: Patricia Mitton
Jan 09, 2016
The Current Effects of
DNA in forensic Criminology
in the 21st CenturyBy: Patricia Mitton
Definition
Forensic Biology- The Scientific analysis of biological evidence to provide objective information on legal matters or those that pertain to criminal and civil law
http://www.fbi.gov/publications/leb/2004/sept2004/sept04leb.htmhttp://www.dnaheritage.com/laboratory.asp
How is DNA used in Criminal Investigations?
http://www.pierce.ctc.edu/proftech/crimJustice/degrees/forensicTech.php
Current Method: DNA TypingProcess
• requires detection and screening of biological evidence
•DNA extracted from a specimen and using PCR amplifies specific regions of DNA
•PCR used to determine a DNA profile
Reason
•to obtain a DNA profile to be compared with suspects, victims, and database samples’ profile’s in order to find a match and catch the perpetrator
STR TypingSTR (short tandem repeat) Typing• Done today using capillary- based electrophoresis or gel
electrophoresisInvolves:1. Extraction of DNA2. Amplification via PCR 3. Separation of PCR products according to length4. Detection via staining or fluorescent dyesPros • Currently the standard DNA typing technology in 11 different
countries• Gives strong, accurate evidence to present in a court caseCons• Mutations have been found to occur while amplifying with PCR such
as nucleotide insertion, deletions or repeats of one or more elements• Need certain amount of DNA(250 picograms) in order to carry out
necessary amplification
STR DNA typing• Used today using capillary-
based, gel electrophoresis
• Focuses on specific region of DNA
• Look for similarities in band patterns to match suspects to the victim
http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-31802002000300004
New Forms of DNA Typing
LCN (Low Copy Number) Typing
• Still uses STR typing but requires less DNA to amplify
• Allows for analysis of small amounts of sample found on evidence such as a gun handle or doorknob
• Method allows for larger chance of mutations
mtDNA (Mitochondrial
DNA) Typing
• Easier to type from small and/or degraded samples because it exists in multiple copies
• Can analyze biological samples that lack a DNA nucleus such as hair, bones and teeth
• Has been successfully typed however there is controversy about interpretation of results
http://www.dnajunction.com/technology/mtdna.php
SNP (Single Nucleotide Polymorphism) Typing
• Can be typed accurately, cheaply and in large volumes
• Avoid many mutations while processing
• Several SNPs lie on same chromosome which cause problems for relatedness in large pedigrees
http://eli-nati.fletzet.com/gallery2/main.php?g2_view=core.ShowItem&g2_itemId=76758
Microbial Forensics: BiocrimesAbout Bio crimes:
• Perpetrators of bio terrorism use pathogens or toxins as weapons
• Low cost for producing pathogenic agents in criminal acts
• Microorganisms and their toxins major bio weapon used because can be grown via single organism or cell
• Bio terrorism will be one of major threats of 21st century
How to stop Bio Crimes:
• Development of a strong, scientifically based microbial forensics program
• Determine procedures for collecting microbial samples at the crime scene
• Come up with a system when a suspected bio terrorism attack is underway
• Learn more about virus’s in nature and where they come from so that we can discover more about genetically engineered virus’
Biocrimes• An example of a biocrime is the
anthrax attack of 2001 caused by spores of the bacterium Bacillus Anthracis.
• Hundreds of people were infected and five people died.
http://www.officeroutlook.com/news/Science/1286.htm
http://webs.wichita.edu/mschneegurt/biol103/lecture20/anthrax_pustule.jpg
http://microbes.historique.net/images/anthrax2.gif
Future Outlook1. Better equipment and accurate machinery for the use of DNA
typing and amplification.
2. The use of SNPs and micro- array technology are looked at to hopefully be major fundamental tools for the analysis of small, degraded samples found at crime scenes with few mutations or problems
3. More developed DNA databanks which store biological samples from crime scenes.
http://science.nasa.gov/headlines/y2004/10sep_radmicrobe.htmhttp://www.cmbi.kun.nl/mcsis/vanhamer/introduction.html
Resources1. _______.(Nov.30,2007).DNA Forensics. Retrieved on December 15,2007 from <http://www.ornl.gov/sci/techresources/Human_Genome/elsi/forensics.shtml>
2. Balding, David J. (2005). Weight-of-evidence for Forensic DNA Profiles. John Wiley and Sons, Ltd.
3. Ricciuti, Edward. (2007). Science 101- Forensics. New York: Smithsonian.
4. Brunette, Stephen A.(2007)”Forensic Evidence” Retrieved on Wednesday Jan. 2, 2008 from http://www.accessscience.com/content.aspx?id=757566#BIB
5. Breeze, Roger G. (2005). Microbial Forensics. London, UK: Elsevier Academic Press.
6. Norah Rudin, Ph.D. (2002). An Introduction to Forensic DNA Analysis. New York: CRC Press.
7. Safterstein, Richard.(2004).Criminalistics:An introduction to Forensic Science. New Jersey: Pearson Education, Inc.
8. Salyers, Abigail A.(Jan. 2004).Microbial Forensics. Retrieved on December 16, 2007 from <http://www.actionbioscience.org/newfrontiers/salyerspaper.html>
9. Steven Lee, "Forensic DNA testing.” (2007).Retrieved on Wednesday Jan. 2, 2008. from <http://www.accessscience.com/content.aspx?id=YB060160>