Short Note: Internal Size Standard for Microsatellite Genotyping

The in-house production of fluorescently labelled

internal size standard offers the advantage of cost saving

over the commercial size standard in microsatellite

genotyping. Based on the reported in-house internal size

standard protocol, we have improved the method by generating

21 DNA fragments (in a standard named as HM-

400) with each size similar to that of the commercial

size standard. The consistent amplification of the correct

fragment size was optimised via primer modulation

for non-templated nucleotide addition by Taq DNA polymerase.

A total of six microsatellite loci were used to

assess the accuracy of HM-400 and the mean standard

deviation of the size data was 0.19. The differences

between the fragment size means for samples sized

using HM-400 and commercial size standard were small

with an average of 0.29 bp. The production cost of HM-

400 was only 10% of the cost of commercial size standard.