Microsatellites, also known as Simple Sequence Repeats (SSRs) or short tandem repeats (STRs), are repeating sequences of 2-6 base pairs of DNA. It is a type of variable number tandem repeat (VNTR). Microsatellites are typically co-dominant. They are used as molecular markers in genetics, for kinship, population and other studies. They can also be used for studies of gene duplication or deletion, marker assisted selection, and fingerprinting. Microsatellites are similar to genes; however, they are short string of nucleotides repeated numerous times (3-100 times) in a DNA code. For instance, CACACACA. These markers often present high levels of inter- and intra-specific polymorphism, particularly when the number of repetitions is 10 or greater. The number of repeats can vary across individual alleles of the same species. If an individual has a microsatellite mutation which doesn’t influence its viability, said mutation may remain in the population as it will be passed down through its offspring. As a result, you can end up with a lot of microsatellite-mutated alleles surviving in the population from generation to generation. Microsatellites are useful for genetic analysis because they can be used to identify individual people. This would be very helpful in criminal cases, population genetics study, etc.
Qsep100 CGE DNA fragment analyzer offers rapid separations with high sensitivity, excellent resolution, ruggedness and ease of operation. Therefore, researchers can easily see the differences of microsatellites repeats (base pairs) result in numerous DNA sizes shown as below.
Figure 1: Qsep100's high resolution analysis of 2bp among the DNA pairs with up to 5 bp.