microsatellite markers – a novel tool in molecular genetics - ijrpc

IJRPC 2012, 2(2) Pokhriyal et al ISSN: 22312781
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Microsatellite Genotyping with a DNA
Sequencer
A DNA sequencer is a highly precise gel
electrophoresis apparatus. PCR products are
loaded onto the gel and separated by size by
applying a charge. A laser scans the gel to
detect bands containing fluorescent dye. The
primers used in the PCR reaction are tagged
with different fluorescent dyes to enable this
detection. The sequencer software converts
the banding pattern into a plot with peaks
corresponding to the width and intensity
(height) of each band. The position of the peak
along the x-axis corresponds to the size of the
DNA product in the band measured in base
pairs (BP). The height/intensity corresponds to
the concentration of the DNA product, which is
a consequence of the efficiency of the
amplification process in PCR. One color is
used for a size standard to calibrate the band
positions with the size of the DNA product. An
asterisk identifies all true microsatellite alleles
in the figures below.
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