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.