Genetic Polymorphism Of15STR Loci In Cantonese, Hakka And Chaoshanese In Guangdong Province And Case Report About A Rare Chimera

Objective To study the genetic polymorphism and frequnencies of15autosomal STR loci inthree main Han populations(Cantonese, Hakka and Chaoshanese) in Guangdong Province. Inaddation, we reported a case of dispermic chimerism in a7year old Chinese boy with normalphenotype. In this part of article, the previous literatures which involved chimerism werereviewed, and the types of chimera, formation mechanisms, detected methods, and diagnosticstrategies were summarized.Method15STR loci were amplified in DNA samples from2174unrelated individuals in threemain Han populations using PowerPlex16system, which were genotyped with ABI3130Genetic Analyzer. Frequencies for15STR loci were obtained, then analyzed all these data withstatistical methods. The genetic distances between Cantonese, Hakka and Chaoshanese werecalculated, and phylogenetic trees were constructed by using Neighbor-Joining method.Result167alleles and602genotypes were observed in506cases of Cantonese.178alleles and704genotypes were observed in907cases of Hakkas.169alleles and667genotypes wereobserved in761cases of Chaoshanese. The data of heterozygosity, matching probability,discrimination power, polymorphism information content and power of exclusion were alsocalculated respectively. In three main Han populations,24rare alleles were found in7STR loci.Based on the results from POPTREE2software, the genetic distances between Hakka andChaoshanese was0.002, and the genetic distances between Cantonese and Hakka was0.003,and the genetic distances between Cantonese and Chaoshanese was0.004. Hakka andChaoshanese were clustered into one group, then clustered with Cantonese into the other group.Conclusion All the allele frequnencies and population data for Cantonese, Hakka andChaoshanese were obtained, which could provide a powerful discrimination tool for forensicapplications. All of the15STR loci in three main Han populations have high power ofdiscrimination and exclusion, they may be available as the candidate genetic markers forforensic application and population genetics purposes. The results showed that genetic distances between Hakka and Chaoshanese was closer than Cantonese, which were basically consistentwith their linguistic culture and ethical history. The conclusion also was supported by the typesand frequencies of rare alleles. The investigations of genetic distances among there differentpopulations are useful to study their origins, migrations and genetic relationships.