Microsatellite
Microsatellite (SSR - Simple Sequence Repeats or SSLP - Simple Sequence Length Polymorphism ) are short, non-coding DNA sequences, which are repeated in the genome of an organism often. Often many repetitions on the same locus ( Auffindeort a sequence ) focus.
The repeated sequence in a microsatellite is very simple. It consists of two to four nucleotides and can be 10 - to 100 - times occur repeatedly. We sequenced the locus of a microsatellite, we obtain sequences like " TAGTAGTAGTAGTAGTAG ... ". Microsatellites are the most common form of repetitive DNA. The most common dinucleotide repeats of the type ( CA) n These account for about 0.5 % of the genome.
Microsatellite can be used for genetic analysis, because the number of repetitions is different in different individuals, and therefore, produces in the enzymatic cleavage with a restriction enzyme, DNA fragments of different length. In this way, polymorphisms in the DNA to be determined.
An analysis of the length of the microsatellite in a particular location ( locus) in the genome is carried out by the PCR analysis. In this case, short synthetic oligonucleotides ( called primers ) may be used which are complementary to those DNA sequences flanking the microsatellite interested. The two (usually different ) PCR products can be separated by gel electrophoresis and their length can be determined with it.