Genes are the blueprints of life. Genes control everything from hair color to blood sugar by telling cells which proteins to make, how much, when, and where. Genes exist in most cells. Inside a cell is a long strand of the chemical DNA (deoxyribonucleic acid). A DNA sequence is a specific lineup of chemical base pairs along its strand. The part of DNA that determines what protein to produce and when, is called a gene.
First established in 1985 by Sir Alec Jeffreys, DNA testing has become an increasingly popular method of identification and research. The applications of DNA testing, or DNA fingerprinting within forensic science is often what most people think of when they hear the phrase. Popularized by television and cinema, using DNA to match blood, hair or saliva to criminals is one purpose of testing DNA. It is also frequently used for other benefits, like wildlife studies, paternity testing, body identification, and in studies pertaining to human dispersion.
While most aspects of DNA are identical in samples from all human beings, concentrating on identifying patterns called microsatellites reveals qualities specific and unique to the individual. During the early stages of this science, a DNA test was performed using an analysis called restriction fragment length polymorphism. Because this process was extremely time consuming and required a great deal of DNA, new methods like polymerase chain reaction and amplified fragment length polymorphism have been employed.
The benefits of DNA testing are ample. In 1987, Colin Pitchfork became the first criminal to be caught as a result of DNA testing. The information provided with DNA tests has also helped wrongfully incarcerated people like Gary Dotson and Dennis Halstead reclaim their freedom.
The ancestors of today's slithery snakes once sported full-fledged arms and legs, but genetic mutations caused the reptiles to lose all four of their limbs about 150 million years ago, according to two new studies.