About DNA Fingerprinting

DNA fingerprinting is a process that matches DNA molecules to one another for the purpose of identification. This process relies on the presence of certain sequences that exist within the human genome. DNA can be obtained from an individual in a variety of ways, including hair fibers, blood and skin cells. DNA fingerprinting is a very important and popular forensic science technique.

• DNA

The Facts

• DNA, or deoxyribonucleic acid, is a chemical structure that creates chromosomes. It is called a double helix because it is made up of two intertwined strands of genetic material. Each of the strands is made up of nucleotides (a sequence of bases). The four bases found in DNA are adenine, guanine, cytosine or thymine. The two strands of DNA are attached at each base, and each of the bases is capable of bonding with one other base, according to "DNA 101" at Washington.edu. In particular, guanine bonds only with cytosine and adenine bonds only with thymine.

Introduction

• All living organisms have DNA; however, what makes each one unique is the specific order of the base pairs. We each have many millions of base pairs in our DNA, but the actual sequence of our base pairs is different from that of everyone else on the planet.

Function

• Identifying sequences in DNA is the primary concept behind DNA fingerprinting, according to Washington.edu. Because there are so many base pairs, scientists have developed a system of identifying their order without going through the entire sequence. DNA sequences repeat, and scientists merely need to identify the particular pattern of the DNA in order to come up with a DNA fingerprint.

Procedure

• Once a DNA sample is taken from a person, it is then physically extracted and isolated from the cells in a laboratory. After isolation, DNA is digested with certain enzymes; the leftover fragments are separated by electrophoresis (a process that disperses particles in a fluid under the influence of an electric field). Once the particles separate according to size, they can then be detected with DNA probes and organized into a fingerprint.

Considerations

• DNA fingerprinting is not a process like regular fingerprinting (that can be used to identify a suspect). Instead, it is a process for comparing DNA samples, according to Washington.edu. For example, DNA fingerprinting is used to determine whether two DNA samples are from the same individuals, two related individuals or two non-related individuals. Furthermore, because small number of sequences of DNA vary greatly among individuals, scientists use this information to analyze the actual probability of the DNA being a match.