Abstract: Objective To investigate the distribution and antigen frequencies of Rh and Duffy blood group antigens in Dai nationality in Yunnan,so as to provide an evidence for the prevention and treatment of blood type-associated hemolytic diseases. Methods Two hundred cases （100 male and 100 females） of Dai people without consanguinity were collected and 100 Han people were taken as control. Blood samples （5 ml,EDTA anticoagulants） were detected for Rh,Duffy and antibody screening. Duffy blood group genotyping was performed using PCR-SSP. Results The RhD positive rate was 98.5% and the negative rate was1.5% in 200 Dai persons compared with the positive rate of 99.0% and negative rate of 1.0% in Han population. Duffy genotyping revealed the distribution of phenotypes of Fy^{（a + b-）} （187/200,93.5%）,Fy^（a+b+）（12/200,6.0% ）,and Fy^（a-b+）（1/200,0.5% ）,no Fy^（a-b-） phenotype was seen,and the genetic frequencies were found to be Fya（0.965） and Fyb（0.035）. In Han population,Duffy phenotypes include Fy^（a+b-） （92/100,92.0% ）,Fy^（a+b+）（5/100,5.0% ）,and Fy^（a-b+）（3/100,3.0% ）,no Fy^（a-b-） phenotype was noted,and the genetic frequencies are Fy^a（0.945） and Fy^b（0.055）. The Dai population presented the prevalence of positive antibodies of 1.5%,among them 2 cases showed E antibodies. Duffy genotyping results showed that,in the 200 samples of Dai nationality,the gene frequency was Fy^a （0.965）,and Fy^b （0.035）. The frequency of the gene was Fy^a （0.945） and Fy^b（0.055） in 100 samples of Han nationality. Conclusion The antigen distribution of Duffy blood group system in Dai nationality is similar to those in Han population although the negative RhD and irregular antibodies are slightly higher in Dai people（P<0.05）.

Key words: Rh Duffy blood group, Antigen distribution, Gene frequency, Dai nationality in Yunnan