Satellite DNA

The study of satellite DNA consists of research into highly repetitive DNA—sequences that tend to reoccur at high frequencies with the nucleotides adenine and thymine. This means that they generally have lower densities and can form a second “satellite” band when the demonic DNA is separated along a density gradient. Altogether, satellite DNA, together with minisatellite and microsatellite DNA, constitute the tandem repeats—the latter usually found in transcription units, and these are thought to originate from a slippage of the replicated chromosome against its template. Often, the base pair repetition will stop proper protein synthesis and this can lead to problems such as myotonic dystrophy. Although this usually appears in adults, it can also occur in children, with a weakening of the muscles in the face, neck, forearms, hands, and lower legs, sometimes with the formation of cataracts in eyes and mental retardation, although many people can survive beyond middle age with the disorder.

The initial research on satellite DNA was at the University of Edinburgh, Scotland, with biochemist Dr. Chris Tyler-Smith's work at the University of Oxford in the late 1980s adding much to our knowledge. Dr. Tyler-Smith became fascinated by the ability to use DNA to show relationships of people [Page 1521]and later became famous for using his work in his work The Genetic Legacy of the Mongols in which he traced the DNA of an individual who was living during the 1000s ce, in the Mongol empire in the DNA of about 16 million people, when the average person alive then would have about 20 descendants sharing that per-son's DNA today.