Deoxyribonucleic Acid (DNA) forensics is a branch of forensic science which focuses on the use of genetic material in criminal investigation. In addition to assisting with human crimes like rape and murder, DNA forensics can also be used to track food-borne epidemics, identify endangered species in shipments of smuggled material, and to trace the history of humans around the world, among other things. Employment in the field of DNA forensics is incredibly varied, although it can be competitive, thanks to television shows like CSI which have raised general public interest in DNA forensics.
DNA is a nucleic acid which contains genetic information. All organisms carry varying amounts of DNA, and the substance contains a vast amount of material which dictates things like how many fingers the organism will have, or what color its hair or fur will be. Laboratory techniques can be used to identify and isolate DNA and then to sequence it. DNA sequencing involves figuring out the order of the four nucleotides in a string of DNA. Several laboratories have focused on sequencing all of an organism's DNA in an attempt to learn more about all members of its species.
In addition to being used to learn more about a species in general, DNA sequencing can also be used to identify specific individuals. In humans, there are around 13 DNA regions which can be used to identify someone, as they are markedly different from person to person. These regions or markers are very useful tools when a crime has been committed, as they can place someone at the scene or exonerate someone else.
In DNA forensics, laboratory staff collect samples from the scene of a crime and analyze them, or put them into secure storage so that they can be used later. These samples include obvious biological material like blood and hair found on a crime scene, along with fingernail scrapings from the victim. They can be used to gather information about the perpetrator, and if a suspect is identified, samples of his or her DNA can be collected for comparison. This is sometimes called “DNA fingerprinting,” because it takes advantage of the unique fingerprint of DNA markers which every human has.
Television shows often glamorize the role of DNA forensics in criminal investigation. While it is certainly an effective and useful tool, it is not a magic bullet. Criminal investigators use this forensic field as a supplement to numerous other criminal investigation techniques in the hopes of identifying and punishing criminals.
By Mary McMahon
Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a All The Science researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.