DNA Forensics

DNA forensics has and can be used for identification purposes. There is one distinctive issue, in DNA trace and matching only 1/10 of a percent of DNA differs from person to person, about 3 million bases. This means that only a very small part of  human DNA is different from person to person. There is a chance though that two people have identical probes in different parts of there DNA. This is very slight  and unlikely.

At a crime scene DNA collection can come from a variety of sources including blood, hair, skin tissue and bone. These specimens are then collected and there DNA sequence is observed. CSO's split the DNA and see which base pair in which order connect to the sequence. The order in which these pairs are arranged is different for every person. The DNA from the suspect is then collected and compared with the sample sequence. Usually one single match of a few base pairs isn't enough for prosecution, but four over five matches in different areas of the sequence may be enough.

There is a chance that another person may have contributed but the chances are very unlikely. DNA forensics has all to do with odds. When convicting an individual the odds of an eye-witnes testimony are 50:50. DNA provides better odds when prosecuting. The more probes that match, the higher the odds. In the end it all comes down to what the judge and jury accept as sufficient evidence.



Website:
, . "DNA Forensics." Human Genome Project Information. 2009. U.S. Department of Energy. 20 May, 2011. <http://www.ornl.gov/sci/techresources/Human_Genome/elsi/forensics.shtml>