Microsatellite
is a stretches of repeats of short nucleotide motifs (eg.dinucleotide, trinucleotide,tetranucleotide
repeats).They are distributed throughout the genome of eukaryotes and prokaryotes.
Microsatellite loci were highly variable in the number of repeats within and
among individual population.
The microsatellite polymorphism caused from slippage mutations which are produced during DNA replication (14). Microsatellite loci can be scored by PCR amplification followed by electrophoresis to separate alleles which differ in length as a result of differences in the number of repeat units. Microsatellites are highly polymorphic and can be used to detect the heterozygosity at a locus. They permit the analysis of multiple loci per individual.
There are several advantages of microsatellite marker over the other genetic markers.
1. Microsatellites are much more
variable because more mutation rates occur in each loci.
2. Microsatellites permit analyses of multiloci per individual population because
there are much more alleles to study on genome.
3. Microsatellite gives high heterozygosity information in population analyses.
4. Microsatellite represents discreet loci with codominant alleles allowing
unambiguous scoring of genotype.
5. Microsatellite DNA markers are selectively neutral because they randomly
distribute throughout the genome.
6. Microsatellite DNA loci are conserved between species and closely related
species allowing primer set to be used across species.
7. Microsatellite DNA analyses are simple, and easier than conventional genetic
markers because the procedures do not require Southern blotting, band patterns
are easy to detect, constantly scorable and comparable, and easy to compare
accurately across gels.
