Forensic+Evidence+and+Genetic+Profiles

Charles Smith and Duy Nguyen

"The evidence never lies" - Gil Grissom, CSI: Las Vegas

The greater the number of markers examined in DNA, the greater the accuracy >
 * __Forensic Evidence and Genetic Profiles__**[[image:doublehelix.jpg width="275" height="204" align="right"]]
 * DNA serves as a main tool for deciding if a suspect is guilty or not
 * It can be tested using methods such as gel electrophoresis.
 * DNA sequence of every person is unique except for identical twins
 * A small set of DNA markers from an indicidual can provide a DNA fingerprint
 * Chance of two people with the same DNA fingerprint is 1/100,000 to 1/1 billion, depending on the number of markers compared
 * Simple tandem repeats (STRs) - the DNA base pairs repeat itself in a sequence, ex: AGGCAGGCAGGCAGGC
 * Forensic Scientists can analyze and match the DNA since STRs vary from one person to another
 * __Examples:__**
 * 1) [[image:forensic_fingerprint.jpg width="360" height="180" align="right" caption="Who done it???"]]At crime scenes, body fluids (blood, semen, saliva, etc.) are collected and brought back to the lab for analysis. From there the CSI can place a suspect at the crime scene or he can also exclude a suspect
 * 2) In rape cases, DNA from the semen can be a strong tool of conviction
 * 3) DNA can also settle dispute over a child since the DNA from the child will be a partial match to the father/mother
 * 4) Endangered animal species' DNA are collected and stored in DNA banks around the world to conserve the genetic material and also used for identification and population management
 * 5) Interesting fact: the largest DNA bank for endangered animals is at the San Diego Zoo, it is also known as the Frozen Zoo