RÉSUMÉ
<p><b>OBJECTIVE</b>To investigate the genetic polymorphisms of 12 X chromosome short tandem repeat (X-STR) loci of Investigator Argus X-12 amplification kit in Guangdong Han population.</p><p><b>METHODS</b>DNA samples from 200 unrelated individuals (100 males and 100 females) and 103 families (59 father-mother-daughter trios and 44 mother-son duos) were extracted and amplified with fluorescence labeled multiplex PCR system. PCR products were separated and genotyped with capillary array electrophoresis.</p><p><b>RESULTS</b>One hundred and thirty-seven alleles,including 9 off ladder alleles (OL allele) were observed at the 12 X-STR loci in the population. Six mutations were observed in 162 meioses. The combined power of discrimination (DP) was 0.999 999 997 in males and 0.999 999 999 in females, and the combined mean exclusion chance (MEC) was 0.999 999 988 in the trio cases and 0.999 998 013 in the duo cases.</p><p><b>CONCLUSION</b>Investigator-Argus X-12 amplification system is highly polymorphic in Guangdong Han population and it is powerful for personal identification and paternity testing.</p>