Rhesus blood group system alleles, haplotypes and most probable genotypes in major Sudanese Populations: An immunological study of ethnology

Abstract

This community-based, prospective and analytical study that aimed to determine the frequencies of Rhesus blood group alleles, haplotypes and genotypes among ten major Sudanese tribes. The study also aimed at establishing Rhesus blood group baseline data for these major Sudanese populations. The study used Rh blood group alleles as markers of ethnic identity to determine a probable common ancestry. This study was conducted in different parts of Sudan during the period of three years. Following informed consent, a total of one thousand venous blood samples were collected from unrelated individuals of the ten selected study populations (one hundred specimens from each tribe were collected into 2.5 mls EDTA containers). The red blood cells were tested for common Rhesus antigens by the Particle gel immune diffusion and ten specimens were tested by the slide agglutination techniques. The gene/allele and haplotypes frequencies and most probable genotypes were determined. Similarities between different Sudanese populations were calculated using Jaccard’s coefficient of similarities. The same coefficient was employed to determine possible origins of these populations. The phenotypic data obtained was referred to as alleles, haplotypes, genotypes this is based on reasonable assumptions that every Rh blood group antigen represents a gene that is always expressed and has a Mendelian dominant mode of inheritance. The ē, c and the D genes were the commonest alleles detected with frequencies of 98.4%, 93.8% and 90.7% respectively. The C and the E genes were the least frequent with 58.4% and 21.0% frequencies respectively. The cDe (Ro) (41.85%) haplotype is commonest among study population whereas the cde (r) (29.3%) with intermediate frequency. The cDE (R 2) (5.95%) and CdE (ry) (0.60%) are least common haplotypes. There are 16 genotypes, the cDe/cde (Ror) is the most common frequent (44.2%), whereas the cDe/Cde (RorI) (21.8%) with intermediate frequency, the Cde/Cde (rIrI) (0.3%) and CdE/CdE (ryry) (0.1%) are the least common genotyes. In conclusion; marked similarities between major tribes could probably point to a common ancestry in very ancient days. Some changes could be seen in Nomadic Sudanese tribes like the Misseria tribe could be explained by their wandering nature. There is great overlap between the linguistic classification of the major Sudanese tribes and this genetics-based categorization. Considerable similarities exist between different Sudanese populations. Linguistic similarities between different Sudanese populations that led to the development of the linguistic classification closely overlap with some genetic markers. The Danagla and the Mahas seem to be genetically different from the Nilo-Saharans and closely resemble the Afro-Asians making their inclusion in this group more logical. The Denka are probably part of the original ancient Sudanese populations from which the others Nilo-Saharan originated. The Halaween population probably maintained their original genetic constitution with minimal genetic change.