Gene frequencies of ABO and rhesus blood groups and haemoglobin variants in Ogbomoso, South–West Nigeria
The distribution and gene frequencies of ABO and rhesus (Rh) blood groups and haemoglobin variants for samples of the Nigerian population at Ogbomoso was determined. Data consisting of records of blood groups and haemoglobin types of different ages ranging from infants to adults for a period of 4 to 6 years (1995 – 2000) was collected from Baptist Medical Centre (BMC), Ladoke Akintola University of Technology Health Centre (LAUTHC) and Oyo State General Hospital (OSGH), all in Ogbomoso, Oyo State, Nigeria. Overall, a total number of 7653, 7053 and 14,845 individuals were typed for ABO and Rh blood groups, and haemoglobin genotypes, respectively. 3824 (50%) were blood group O, 1750 (22.9%) were blood group A, 1629 (21.3%) were blood group B and 450 (5.9%) were blood group AB. This distribution differs significantly (P<0.05) from those expected under the Hardy Weinberg law. The proportion of the individuals belonging to the various ABO blood groups also varied significantly (P<0.05) over the period of the study. Overall gene frequencies for the A, B and O alleles were 0.15, 0.15 and 0.70, respectively. For the Rh blood group 6823 (96.7%) were Rh-positive (DD and Dd) while 230 (3.3%) were Rh – negative (dd). The distribution and proportion of individuals belonging to each group did not differ significantly from those expected under the Hardy Weinberg law (P>0.05). The gene frequencies of D and d alleles were 0.82 and 0.18, respectively. Six haemoglobin genotypes were recorded in the order of AA (68.1%) > AS (21.0%) > AC (5.7%) >SS (3.0%) >SC (2.0%) >CC (0.3%). The gene frequencies were 0.81, 0.14 and 0.04 for A, S and C alleles, respectively. Our results are representative of the distribution of these genetic variants in Nigeria.
Keywords: Gene frequency, blood groups, haemoglobin, Nigeria