DNA Fingerprinting

According to Dan Gramer, director of laboratory operations with Cellmark Diagnostics in Frederick, Md., the possibility of two people sharing the same DNA fingerprint is "1 in 1,000,000,000,000,000- a million billions" (Froelich and Leyden 1).
             With such great odds, DNA can be tested to find the genetic fingerprint of a person. DNA testing, or fingerprinting, is a difficult process that looks for differences among samples of the nucleic acid. DNA fingerprinting derived from the use of polymorphism in medicine, which are silent variations between the genomes of different people. DNA tests also work with sites in DNA that have different lengths because of their variable numbers of repeated units (VNTRs) (Housman 543). The VNTRs are where DNA goes into "the genetic equivalent of a computer programming loop" and copies itself repeatedly. This takes place at the end of each chromosome and/or in tons of other identifiable locations along "DNA's six-foot length" (Schefter 2-3). This process results in a genetic fingerprint. A fingerprint comes from a purified DNA sample which has been made into billions of copies and identified by types found in that sample (Cheney 3). Genetic fingerprinting uses the complex technology of an electrical field to separate DNA pieces by length and radioactive material to create a mark on an X-ray film of and individual's DNA fingerprint (Froelich and Leyden 3). Examining a DNA fingerprint, one expert commented, "They look like nothing so much as ink spots, but these marks are more than that: they are a genetic portrait, an immutable chemical signature" (Cheney 1).
             One genetic test, the Polymerase Chain Reaction (PCR), uses speed and precision to make a DNA fingerprint. The test itself is a significant advancement in genetic technology because of its complex yet significant techniques. The PCR test looks at six different inherited traits, each controlled by a specific gene.