Uses of Microsatellites

Microsatellites, also known variable number of tandem repeats (VNTRs), are short DNA segments with repeated sequences. These segments naturally occur in most living organisms' noncoding DNA. Unrelated to to the synthesis of proteins and other cellular functions, noncoding DNA -- often referred to as "junk DNA" represents the majority of DNA in humans. Biologists in the early 1990s began investigating microsatellites. As of 2011, science recognizes the importance of such segments, widely used in biological research.

Analisis of Natural Populations

• Scientists use microsatellites to study the evolutionary links within natural populations of wild animals, such as foxes. The island fox (Urocyon littoralis), a diminutive form of the mainland gray fox (Urocyon cinereoargenteus), occupies California's Channel Islands. These two species show similar patterns in the sequences of their microsatellites, suggesting a linked evolutionary past. The analysis of microsatellites often involves a polymerase chain reaction (PCR) technique, which amplifies a single microsatellite and generates millions of copies of the DNA sequence.

Determination of Genetic Diversity

• Microsatellitescan help determine the differences across organisms with similar genetic codes. For instance, the nine species of the genus Lycopersicon (tomato plants) show different microsatellite sequences. Scientists used these microsatellite polymorphisms to determine the relation among the modern and wild species of tomato. Understanding DNA microsatellites also helps scientists to develop new variety of plants with specific characteristics, such as resistance to plagues and pesticides.

Cancer Research

• Cancer results from genetic alterations or replication errors in cell DNA; cancer research often relies on analysis of the disease on a microsatellite level. Through the analysis of microsatellite alterations in patients with cancer, scientists found a genetic link and the possibility of early diagnosis according to the familial cancer history. Microsatellite testing can prove useful in detecting patients with high risk of developing some types of hereditary cancer.

DNA Testing

• Microsatellites pay a role in DNA testing in forensics contexts, both for human and wildlife cases, as match identities for microsatellite profiles are often extremely high. Microsatellites are an important tool in mapping genomes -- the genetic code that defines one species, such as the recent mapping of the human genome (see the link in the Resources section). Microsatellites can also play a role in paternity tests and evolutionary studies of human ethnicity.