How DNA testing works

One of the most important discoveries of the 1950s is deoxyribonucleic acid, commonly known as DNA, the stuff on which modern forensic science is based.

DNA’s double-helix structure, similar to a spiral staircase, was discovered by four scientists: James Dewey Watson, Francis Crick, Maurice Wilkins, and Rosalind Franklin.

All known cellular life and some viruses contain DNA, which is a "nucleic acid that contains the genetic instructions for the development and functions of living organisms," according to Wikipedia’s online encyclopedia.

Health Secretary Francisco Duque III said each organism, including humans, has its own DNA composition.

"There are no two persons who have similar DNA. It’s our genetic imprint. It makes us unique from each other," he told The STAR.

Duque said this genetic imprint, if used properly, is effective in establishing the identity of a crime suspect and a crime victim and even paternity and other familial relationships.

Forensic scientists accomplish this by examining the DNA sequence unique to that human or species.

The website of the Human Genome Program of the United States’ Department of Energy Office of Science showed that in identifying individuals, "forensic scientists scan 13 DNA regions that vary from person to person and use the data to create a DNA profile of that individual," sometimes called a "DNA fingerprint."

The website showed that "there is an extremely small chance that another person has the same DNA profile for a particular set of regions."

DNA examination is also used to identify catastrophe victims, endangered and protected species; detect bacteria and other organisms that may pollute air, water, soil and food; match organ donors with recipients in transplant operations; determine pedigree for seed or livestock breeds and authenticate consumables such as caviar and wine.

The website further stated that "only one-tenth of a single percent of DNA (about three million bases) differs from one person to the next."

"Scientists can use these variable regions to generate a DNA profile of an individual, using samples from blood, bone, hair and other body tissues and products," the website stated.