Polymorphism of the Microsatellite DXS8377 in a Population of Northern Thai Males

Objective: This research investigated the polymorphism of the X-chromosomal short tandem repeats (X-STR) DXS8377 in Northern Thai males. Methods: Genomic DNA was extracted from blood or buccal cells of 200 unrelated healthy individuals using Nucleospin® Blood or Nucleospin® Tissue (Macherey-Nagel), respectively. The DXS8377 locus was amplified by polymerase chain reaction (PCR) and the PCR product was analyzed by agarose gel electrophoresis. The allelic ladder was constructed and the size of all PCR products was analyzed by polyacrylamide gel electrophoresis using allelic ladder as a marker. The nucleotide sequences of the different-sized PCR products were analyzed to identify the DXS8377 alleles. Lastly, the Polymorphic information content (PIC) and Power of discrimination (PD) of DXS8377 DNA marker were calculated and the analysis of population relationships was performed using chi-square test of homogeneity. Results: Eleven DXS8377 alleles were observed in the study population, the allele 49 was the most frequent with the allele frequency of 0.4400. According to previous studies, allele 49 was found in all of the populations studied and it was common among various populations. The polymorphism and the probability of DXS8377 to discriminate two unrelated individuals were moderate with a PIC and PD of 0.6973 and 0.7305, respectively. Most interestingly, the DXS8377 DNA marker was able to differentiate Mongoloid from Caucasoid and Negroid and it was also able to differentiate Northern Thai males from other Asian populations, including Korean, Japanese and Chinese. Conclusion: Even though DXS8377 possessed moderate PIC and PD, this DNA marker was able to differentiate Mongoloid from Caucasoid and Negroid and it was also able to differentiate Northern Thai males from Korean, Japanese and Chinese.