GENOTYPIC AND ALLELIC FREQUENCIES OF ABO AND Rh BLOOD GROUPS AMONG STUDENTS OF BUTAJIRA PREPARATORY SCHOOL, GURAGE ZONE, SOUTHERN NATIONS,NATIONALITIES AND PEOPLES’ REGIONAL STATE, ETHIOPIA.

Abstract

Genotypic and allelic frequencies of ABO and Rh blood group systems are known to vary worldwide geographically and from one population to another. The aim of the present study was to determine the genotypic and allelic frequencies of ABO and Rh blood group systems and to determine the predominant blood groups among Butajira Preparatory School students, Gurage zone, Southern Nations, Nationalities and Peoples’ State, Ethiopia. A total of 400 Students, with the age group 18-24 years took part on voluntary basis in the study, the ABO and Rh blood types were determined using agglutination reaction with antisera. Blood group allelic and genotypic frequencies were estimated from the phenotypic frequencies by assuming HardyWeinberg principles for the whole population. The overall ABO Blood group phenotypic frequency distribution was A(0.325), B(0.195), AB(0.06) and O(0.42). The allelic frequencies were IA (0.2157), IB (0.1369) and IO (0.6474) and the genotype frequencies were IAIA(0.0465), IAIO(0.2793), IBIB(0.0187),IBIO(0.1773), IAIB(0.0591) and IOIO(0.4191). Differences in phenotypic frequencies of the ABO and Rh blood groups among the school students were statistically tested by using Chi-Square. Blood type O was the predominant blood type in the study area. Blood type AB had the lowest phenotypic frequency. The order of ABO blood group allelic frequencies were IO > IA> IB in the overall samples of the students. With respect to Rhesus factor, the prevalence of Rh- positive was found to be 90℅ while that of the Rh-negative was 10℅.The frequencies of the two Rh alleles D and d were 0.6838 and 0.316, respectively.