3. Results
3.1. Frequency of ABO and Rh blood grouping
The four hundred and forty one (441) Secondary and Prepara- tory school students selected randomly consist of 255 males and 186 females between ages 18 and 20. There are differences in frequency distribution of the blood group (ABO) among the ethnic groups of the students. Blood group O has the highest frequency while blood group AB has the lowest frequency (Table 1). Blood group O is highly distributed in the Meskan ethnic group than Silte and Sodo ethnic groups. The frequency of blood group A is higher in Sodo than Silte and Meskan eth- nic groups and blood group B is dominant in the Sodo ethnic group than Silte and Meskan. Blood group AB has equal fre- quency in the three ethnic groups.
The variations in the frequency distribution of Rh-positive and Rh-negative among the three ethnic groups followed the same pattern as shown in Table 2. The percentage of distribu- tion of the ABO blood group and ethnic groups varies signif- icantly based on the Rh blood group (Table 3). The ABO blood group distribution based on Rh in Sodo and Silte is the same in blood group A with Rh positive (26.53%) but in Meskan the percentage of blood group A is reduced to
20.41% of the total population. As it is indicated in Table 3, blood group AB with Rh positive has a small percentage dis- tribution in the three ethnic groups than blood group A and B. Blood group O with Rh positive of Sodo was 36.73% and that of the Silte was 40.14% which is higher than the Sodo eth- nic group and 46.26% for the Meskan ethnic group. So, blood group O with Rh positive is dominant in the Meskan ethnic group. As compared to the other blood groups, blood group O with Rh positive percentage distribution varies significantly in the three ethnic groups. However, the percentage distribu- tion of Rh negative is very small or rare in the three represen- tative groups.