ABSTRACT
In this study, the HLA-DRB1 and -DQB1 molecular diversity of two Berber-speaking populations of Southern Tunisia was analysed. Genetic comparisons indicate that both populations exhibit peculiar profiles for HLA-DRB1, as they diverge significantly from most other North Africans, while being highly diversified. At the opposite, they are much less differentiated from neighbouring populations according to the HLA-DQB1 polymorphism. Overall, the HLA class II genetic structure of Arab and Berber-speaking populations from Tunisia, and of North Africa as a whole, is complex and cannot be simply explained by geographic or linguistic differentiations. The present North African genetic pool has probably been shaped by both genetic drift and the contribution of genetically heterogeneous populations during the history of settlement of North Africa.
Subject(s)
Genes, MHC Class II , Polymorphism, Genetic , Africa, Northern , Alleles , Arabs/genetics , Ethnicity/genetics , Gene Frequency , HLA-DQ Antigens/genetics , HLA-DQ beta-Chains , HLA-DR Antigens/genetics , HLA-DRB1 Chains , Haplotypes , Humans , Linkage Disequilibrium , TunisiaABSTRACT
A "new" rabbit immunoglobulin allotype belonging to the VHa series (a109) that seems particular to the Iberian O. cuniculus has been detected in a Portuguese wild rabbit population. This allotype was found in the wild population of Spain but not in those of France and Zembra island (Tunisia). Using antisera and monoclonal antibodies raised against already known VHa allotypes, we found that a 109 presents cross-reactivity with a1, a3, a100, a101, a107 and a108 allotypes. On the basis of studies of these cross-reactivities, we show that a109 is constituted of at least three variants (or subfamilies of variants) possessing determinants common with either a1 and a109, a3 and a109 or a1, a3 and a109 allotypes. These results are discussed according to recent data relative to generation of antibody diversity in rabbit.
Subject(s)
Immunoglobulin Allotypes/genetics , Immunoglobulin Heavy Chains/genetics , Immunoglobulin Variable Region/genetics , Rabbits/genetics , Rabbits/immunology , Animals , Cross Reactions , Genetic Markers , Immunoglobulin Allotypes/immunology , Immunosorbents , Pedigree , RadioimmunoassayABSTRACT
An allotype (a107) which strongly cross-reacts with a1 specificity has been detected in the wild rabbit population of Zembra Island, Tunisia. It is different from the a1 allotype since an anti-a1 monoclonal antibody recognizes a1 but not a107 specificity. Genetic data and localization on the Fd fragment are in agreement to designate this allotype to the a series. The a107 allotype has been found in wild rabbit populations of Spain and Portugal but not in France.
