Judicature Genes and Justice
The Growing Impact of the New Genetics on the Courts

November-December 1999  Vol 83(3)

 
 
DNA profiling vs. finger prints
DNA is similar to fingerprint analysis in how matches are determined. When using either DNA or a fingerprint to identify a suspect, the evidence collected from the crime scene is compared with the "known" print. For example, if the evidence found at the crime scene is an individual's right thumb print, when a suspect is identified, his right thumb print (or the "known" print) would be compared to that evidence.

Similarly, when DNA testing is performed on crime scene evidence, it is performed on certain locations ("loci") in a DNA sample. When a suspect's DNA is analyzed, it is analyzed at the same loci in order to make a valid comparison. In both DNA and fingerprint analysis if a single feature of the DNA profile or fingerprint is different, it is considered to be "an exclusion" and not to have come from that suspect.

Because the DNA contained in cells constitutes the chemical blueprint for that person's entire biological make-up, it can potentially provide a broader range of information about an individual than can a fingerprint. For example, investigators use current technology to determine gender from DNA evidence whereas a fingerprint that cannot be found in a database remains of unknown gender. So while the current forensic DNA database identifies individuals based on loci to loci comparison, future applications of DNA technology has the potential to add significantly more information about the evidence than can the fingerprint. 

Return to From crime scene to courtroom...


Christopher H. Asplen is an assistant United States attorney and Executive Director of the National Commission on the Future of DNA Evidence.
 
 
Table of Contents
The online presentation of this publication is a special feature of the Human Genome Project Information Web site.