Abstract: A survey on the distribution of 4 red cell blood group systems, including ABO, Rh, MN and P, was carried out in 1997 on the Jino , Blang and Lahu ethnic groups in Yunnan Province, China. One hundred students from each of the three ethnic groups ( Jino in Jinghong City; Blang in Menghai County; Lahu in Lancang County ) were investigated. All students investigated were unrelated, their parents and grandparents were of the same ethnic groups. The results showed that in ABO system, the gene frequency p was 0. 2420 ( Lahu) , 0. 2144 ( Blang ) and 0. 0779 ( Jino) ; gene frequency r was 0. 6971 ( Jino) , 0. 5964 ( Blang ) and 0. 5288 ( Lahu). In Rh system, the most common phenotype was CCDee in both Jino and Lahu ethnic groups ( 56% in Lahu; 47% in Jino) , and CcDE-was also common ( 37% in Jino; 27% in Lahu) . The phenotype CCDE- was not observed in Jino and Blang while the phenotype ccDee was not observed in Blang and Lahu. The gene frequency o f CDe was the highest among all haplotypes, 0. 7433 for Lahu and 0. 6950 for Jino and the gene frequency of cDE was the next, 0. 2517 for Jino and 0. 1871 for Lahu. No case of Rh negative was observed in all of the three ethnic groups. In MN system, gene frequency m > n was observed in all of the three ethnic groups. In P system, the gene frequency P1 was 0. 5099( Lahu) , 0. 4690( Blang ) and 0. 4359( Jino ) , respectively. All these figures are higher than those of any other ethnic groups investigated allover the country.

Key words: Ethnic groups, Red cell blood group systems, Gene frequency , Human population genetics