Objective:To investigate the polymorphisms of 3 short tandem repeats (STR) loci (CSF1PO,TPOX, TH01) in Maonan nationality in Guangxi province and to explore the origins of Maonan nationality.Methods: Totally 200 unrealated individuals were analyzed by STR genescanning marked with fluorescence.Allele frequen- cy and genetic distance were calculated and phylogenetic tree was constructed.Results:There were 18 STR allele in 3 STR of Maonan nationality with its frequencies ranging from 0.0050 to 0.452 5.The aver...