How DNA Fingerprinting Helps in Forensic Science
DNA fingerprinting to identify murderers became a staple of American crime shows in the 21st century, but it's been a staple of forensic science since 1985.
First used to identify hereditary disease genes, DNA fingerprinting quickly became a tool in crime investigation and convicted its first criminal in 1988.
It has also freed innocent prisoners, identified the victims of the 9-11 attacks, and tracked the history of human migration.
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DNA
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All individual plants and animals have unique DNA (deoxyribonucleic acid) patterns in the nuclei of their cells, except identical twins.
Extracted from bodily fluids or taken from bone, teeth, skin or hair roots, DNA can indicate the sex of the sample, but as yet does not identify physical traits.
Forensic scientists compare the genetic material in the same locations (loci) in the samples. If one feature is different, it is not a match.
Daniel Drell of the Human Genome Program says only one-tenth of 1 percent of anyone's genome differs from others (of 3 million bases). Scientists design 13 DNA probes to bind to certain DNA sequences. These create a DNA fingerprint unique to the individual. The odds that two non-twins will have 13 matching loci are a billion to one. -
Human Relations
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Forensic scientists have analyzed skin cells or genetic material from old bones and teeth to reunite families separated by the Holocaust and restore children of the "disappeared" to their Argentine families.
DNA is used to match organ donors with recipients, determine pedigrees for purebred animals and plants and authenticate fine wines or caviar.
Scientists can determine paternity and identify male relationships using markers on Y chromosomes.
DNA fingerprinting identified the son of King Louis and Marie Antoinette and Russia's Czar Nicholas.
Bioanthropologists have traced human migration around the world by identifying family lineages using DNA markers.
Animals
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DNA can identify endangered or protected animals and help convict poachers.
The DNA from endangered animals has been preserved in banks.
DNA from grizzly bears has been banked to help these declining animals preserve a healthy genetic pool.
Identification
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Missing persons, lost children and accident or catastrophe victims can be identified by matching their DNA fingerprints with relatives.
The FBI's Combined DNA Index System (CODIS) computers have two indexes of DNA fingerprints of known criminals as well as unknown samples from crime scenes.
The National Football League used synthetic DNA to mark the footballs used in the Super Bowl to prevent fraud in sports memorabilia.
DNA was used to mark Olympic products for the Sydney Games and is used to identify artwork and rare and valuable items for authentication.
Disease Markers
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Humans can find out if they carry the genes for diseases that are in their family.
Scientists use DNA to identify bacteria and other organisms that contaminate air, water, soil and food.
DNA analysis that identifies weaknesses or susceptibility to diseases or insects is used to modify food crops.
References
- Photo Credit Image by Flickr.com, courtesy of chris elward
