DNA-based Biometrics


What is DNA?

Deoxyribonucleic acid (DNA) is the genetic material found in most organisms, including humans. Each individual human is identifiable by hereditary traits found in their DNA, which is located in the nucleus of the cells as well as the mitochondria. DNA serves as a genetic code that is unique to every organism, no two being exactly alike; only identical twins are an exact DNA match. An organism’s DNA code is comprised of four bases: adenine (A), guanine (G), cytosine (C), and thymine (T). These bases combine in a specific sequence to form base pairs that determine the anatomy and physiology of the organism. Each base pair is attached to a sugar and phosphate molecule creating a nucleotide. Nucleotides compose two long strands connected by the base pairs in a ladder-like formation that form the common spiral known as the double helix. [2]


In the case of human beings, there are about 3 million bases, 99% of which are the same from person to person. The variations found in the final 1% are the means by which DNA becomes unique to each individual. [2] The final 1% also serves as the foundation for DNA biometrics, being the location of the unique traits by which DNA recognition can identify or verify the identification of an individual person. Image: [5]

How DNA recognition works?

The cells that contain DNA share genetic material (information) through chromosomes. Humans have 23 chromosomes that house a person’s DNA and their genes. Of the 46 total chromosomes, 23 come from each parent of an offspring. 99.7% of an offspring’s DNA is shared with their parents. The remaining .3% of an individuals DNA is variable repetitive coding unique to an individual. This repetitive coding is the basis of DNA biometrics. DNA recognition uses genetic profiling, also called genetic fingerprinting, to isolate and identify these repetitive DNA regions that are unique to each individual to either identify or verify a person’s identity. [1]

The basic steps of DNA profiling include:

  1. Isolate the DNA (sample can originate from blood, saliva, hair, semen, or tissue)
  2. Section the DNA sample into shorter segments containing known variable number tandem repeats (VNTRs)—identical repeat sequences of DNA
  3. Organize the DNA segments by size
  4. Compare the DNA segments from various samples

The more repeats of sequences there are for a given sample, the more accurate the DNA comparison will be, thus decreasing the likelihood of the sample matching multiple individuals. In other words, the more detailed the sample is, the more precise the comparison is in identifying the individual who possesses the DNA from the sample. A few drawbacks of this technique are the depth of the procedure, the physical invasiveness of obtaining the DNA sample, and the time required to perform a DNA comparison. Also contamination of the sample renders the comparison impossible. [1]

Most often, DNA biometrics is used for identification purposes as opposed to verification because the technique has yet to automate through technological advances. DNA sequencing, the process of generating a DNA profile, is compared to DNA samples previously acquired and catalogued in a database. The most common DNA database in existence is the CODIS System used by the Federal Bureau of Investigation. DNA biometrics technology is not advanced enough for universal use. Current DNA biometrics is far from that depicted in the movies. [4]

The Future of DNA Biometrics

The future of DNA biometrics in terms of physical and network security will rely on experts’ ability to make it a more cost efficient method of identification. [4]Whether this means portability or mass production, development will depend on technological advances in the areas of DNA sequencing and sample comparison techniques. A professor at National University in San Diego, California is working on creating a portable DNA sequencer that will combine existing DNA biosensors with a new device called the ion-selective field-effect transistor (ISFET). This product would allow a handheld device to perform the same activities that currently must take place in a laboratory. [3]As these kinds of advancements take place, the implementation of DNA biometrics into civilian business environments for use in physical and network security will expand to a great extent. The precision and accuracy of DNA recognition will make it a much desired means of identification, and hopefully verification, in the foreseeable future.

1. Biometrics Newsportal.com. “DNA Biometrics.” Biometric News Portal. 04/03/2008. <http://www.biometricnewsportal.com/dna_biometrics.asp>
2. Genetics Home Resource Website. “What is DNA.” 03/28/2008. United States National Library of Medicine. National Institute of Health. 04/03/2008. <http://ghr.nlm.nih.gov/handbook/basics/dna>
3. Inderscience Publishers. "Handheld DNA Detector." ScienceDaily 03/17/2008. 04/03/2008. <http://www.sciencedaily.com/releases/2008/03/080310173246.htm>
4. Soltysiak, Shannon and Hamed Valizadegan. “DNA as a Biometric Identifier.” Computer Science and Engineering Department. Michigan State University. 04/03/2008. <http://www.cse.msu.edu/~cse891/Sect601/CaseStudy/DNABiometricIdentifier.pdf>
5. "Investigation: DNA Analysis Unit II."FBI Laboratory 2005 Report. Federal Bureau of Investigation. Quantico, VA: 2005 <http://www.fbi.gov/hq/lab/labannual05/labannual05.htm#page_1>
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