Its accuracy has made DNA evidence virtually unassailable. A landmark report published by the National Research Council in 2009 dismissed most forensics as unproven folk-wisdom but singled out DNA as the one forensic science worthy of the name. Yet in recent years Hampikian and other geneticists have begun to question the technology. Thanks to a series of advances-including the polymerase chain reaction, which can multiply tiny amounts of DNA-it's now possible to detect DNA at levels hundreds or even thousands of times lower than when DNA fingerprinting was developed in the 1980s. Investigators can even collect "touch DNA" from fingerprints on, say, a glass or a doorknob. A mere 25 or 30 cells will sometimes suffice.
This heightened sensitivity can easily create false positives
Explore electrophoresis with The Amoeba Sisters! This biotechnology video introduces gel electrophoresis and how it functions to separate molecules by size. Restriction enzymes, DNA ladders, and DNA fingerprinting briefly introduced.
This site provides biochemical methods and computer tools to allow students to use their own DNA "fingerprints" as a starting point in the study of human evolution. Two experiments are currently available, which are supported by reagents and ready-to-use kits available from Carolina Biological Supply Company.