FREQUENCIES OF ABO AND RH-D BLOOD GROUP ALLELES AMONG STUDENTS OF FOUR ETHNIC GROUPS IN MECHARA SECONDARY AND PREPARATORY SCHOOL,WEST HARARGHE, OROMIA

Frequencies of ABO and Rh-D blood groups vary worldwide and are not found in equal numbers even among different ethnic groups. Some variations may even occur within one ethnic group in different geographical areas. Therefore, this study was conducted to determine the frequencies of ABO and Rh-D blood group phenotypes, alleles and genotypes among Students of Oromo, Amhara, Argoba and Somali ethnic groups in Mechara Secondary and Preparatory School,West Hararghe, Oromia. A total of 449 students were purposely selected among school Students and tested for ABO and Rh-D blood groups antigens. Blood groupings were done using open slide method. The frequencies of ABO and Rh-D blood groups phenotypes were expressed in percentages and the modified Hardy-Weinberg Law was used to determine allele and genotype frequencies whereas Chi-square test was used to compare observed phenotypic frequency distribution of ABO and Rh-D blood groups with that expected under the HardyWeinberg law . In the overall sample, the observed O, A, B, and AB blood group percentages were 42.1%, 29.2%, 20.48% and 8.24%, respectively. The Rh-D positive incidence was 98.84%, while Rh-D negative was 1.34% in the overall sample. The order of ABO blood group allele frequencies were IO > IA > IB in the overall samples and in each of the four ethnic groups. The allele frequencies of IO , IA , and IB in the total sample were found to be 0.64, 0.21 and 0.16 respectively. The allele frequencies were 0.64 IO , 0.22 IA and 0.14 IB for Oromo, 0.66 IO , 0.19 IA and 0.15 IB for Amhara, 0.61 IO , 0.20 IA and 0.19 IB for Argoba and 0.63 IO ,0.22IA ,0.15 IB for Somali ethnic groups. The Rhesus blood group allele frequencies of the total sample were 0.884 D and 0.116 d.. There were no significant differences among ethnic groups in blood type frequencies.