PHENOTYPIC, GENOTYPIC AND ALLELIC FREQUENCIES OF ABO AND Rh(D) BLOOD GROUPS AMONG STUDENTS BELONGING TO SOME SELECTED ETHNIC GROUPS IN GERESU DUKI PREPARATORY SCHOOL IN WOLISO TOWN, OROMIA

The ABO and Rh blood groups are the most important blood groups despite the long list of several other blood groups discovered so far. The ABO and Rh blood groups varies worldwide and are not found in equal numbers even among ethnic groups. Therefore, the objective of the study was to estimate phenotypic, genotypic and allelic frequencies of ABO and Rh blood groups among students of Oromo, Amhara and Gurage ethnic groups in Geresu Duki preparatory school in Woliso town, Oromia, Ethiopia. The study was conducted on 470 (48%) out of 985 students in Geresu Duki preparatory school who were enrolled in 2016/17. These were purposively selected and the sample were divided into three ethnic groups, Oromo ,Amhara and Gurage and stratified along ethnic lines. The frequencies of ABO and Rh(D) blood group phenotypes were determined and Hardy-Weinberg Law was used to determine allelic and genotypic frequencies. In the overall sample, the O, A, B, and AB blood group percentages were 40%, 30.64%, 21.70% and 7.66%, respectively. The most prevalent blood group was type O followed by A, B, and AB. Blood group O had the highest frequency while blood group AB had the least distribution. The Rhesus positive frequency was 96.38%, while Rhesus negative was 3.62% in the overall sample. The order of ABO blood group allele frequencies was IO> I A> IB in the overall samples and in each of the three ethnic groups. The overall allelic frequencies of the population as they were calculated using the extension of the Hardy– Weinberg law were 0.63, 0.21 and 0.16 for IO , IA and IB alleles, respectively. Also on the Rhesus status, the allelic frequencies were 0.81 and 0.19 for D and d alleles, respectively.The Chi-square test was done to compare observed phenotypic frequency distribution of ABO and Rh (D) blood groups with that expected .Overall results from this study show that phenotypic, genotypic and allelic frequencies of ABO and Rh blood group were varied in different ethnic groups.