Detection of
microsatellite variation
Microsatellite variation is detected by a combination of
PCR amplification and electrophoretic
separation. Once a microsatellite locus is
identified, two PCR priming sites with
unique DNA sequences are identified on either
side of the repeat region [top]. PCR amplification
generates a DNA fragment of a particular size
[middle], depending on the number of repeats in the
microsatellite locus present. The size of the allele can
be measured by the use of DNA size markers
run simultaneously with the PCR product
[bottom].
In
the example, the individual is heterozygous for
two alleles that are both amplified by the same PCR
primers and are detected as two fragments
of 184bp and 188bp.