9781422273425

What Is DNA Profiling? DNA profiling uses genetic markers from biological evidence to identify suspects in crimes or to identify family relationships. DNA, short for deoxyribonucleic acid , is the genetic material inside of cells that all life forms (animals, plants, and humans) use to reproduce cells and maintain life. Although every human being is unique, 99.9 percent of our DNA is actually identical to everyone else’s. Our uniqueness comes from the one- tenth of one percent of DNA that is unique and uniquely arranged inside of our cells. Even identical twins have some differences in their DNA that can be identified through sophisticated DNA profiles. DNA profiles can identify probable, though not certain, origins of biological evidence found at crime scenes. They can also help to reveal family relationships, including fathers, mothers, children, siblings, and more distant ancestral relationships. They can also be used to identify people who have been victims of natural or human-caused disasters. For example, DNA profiling helped to identify victims of a massive tsunami in Thailand in 2004. It also helped to identify the remains of people who died in the September 11, 2001, attacks on the World Trade Center in New York City. DNA profiling began in the 1980s with DNA fingerprinting, invented by Dr. Alec Jeffreys, a British scientist. Dr. Jeffreys developed an electrostatic technique that created a bar-like pattern of DNA in photo-sensitive gel. He had hoped to find a cure for rare genetic illnesses, but ended up creating a method that solved crime, including the murders of two girls in a town close to the university where he worked. To create a reliable DNA profile, trained analysts must follow a strict process to prevent contamination and misidentification. They analyze DNA evidence and interpret it using contemporary techniques. DNA profilers produce a chart called an electropherogram, which shows genetic markers called alleles , which indicate individual DNA characteristics that can be identified and compared.

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