The contribution of HLA class I and II alleles and haplotypes to the investigation of the evolutionary history of Tunisians

Abstract

The frequencies of HLA class I and class II alleles and haplotypes of 104 healthy unrelated Tunisians were analyzed by high-resolution PCR-reverse dot blot hybridization, and was compared with other Mediterranean and Sub-Saharan Africans using genetic distances measurements, Neighbor-joining dendrograms, correspondence, and extended haplotypes analysis. The most frequent HLA class I A alleles were A*02, A*24, and A*30, while the most frequent B alleles were B*44, followed by B*50, B*51, and B*07. Among HLA class II DRB alleles analyzed, the most frequent were DRB1*0301, DRB1*0701, DRB1*1501, followed by DRB1*1303 and DRB1*0102; for DQB1, they were DQB1*0301 and DQB1*0201. Three-locus haplotype analysis revealed that A*03-B*07-DRB1*1503 and A*02-B*44-DRB1*0402 were the most common HLA class I and II haplotypes in this population. Compared with other communities, our result indicate that Tunisians are very related to North Africans and Western Europeans, particularly Iberians, and that Tunisians, Algerians, and Moroccans are close to Berbers suggesting little genetic contribution of Arabs who populated the area in 7th to 8th century AD. The similarities and differences between Tunisians and neighboring and related communities in HLA genotype distribution provide basic information for further studies of the MHC heterogeneity among Mediterranean and North African countries, and as reference for further anthropological studies.

HLA-A, -B and -DRB1 allele frequencies in Cyrenaica population (Libya) and genetic relationships with other populations

“…The highest frequencies of HLA-A alleles were observed in the allele group HLA-A ⁄ 02 (23.3%). This value is also highest in other Mediterranean and African populations [12,13,23,[24][25][26][27][28][29][30]. HLA-A ⁄ 01 (11.4%) has a similar distribution to those reported in Moroccan (12.1%) [12,31,32], and Algerian (11.9%) [14] and other populations [32] and Tunisians (17.5%) [34] but lower than those reported for Tunisian Berbers (24.8%) [39].…”

“…The frequency of this haplotype in the Cyrenaica population is higher compared to other North African populations, such as Tunisians (HF: 1.8%) [13] and Tunisians Ghannouch area (HF: 2.5%) [33].…”

“…HLA polymorphism in the Libyan population has not been investigated previously. Until recently, HLA class I and II allele distributions in North Africa were available only for Tunisia, Algeria and Morocco [12][13][14].…”

Kell Blood Group System Polymorphism in an Urban Tunisian Population

“…This overlapping of allele distribution among Caucasian, Tunisian, and African populations can likely be explained by the invasion of North Africa by the Romans, oriental Arabic Muslims, and some sub-Saharan tribes hundreds of years ago and confirms the mixed origin of the Tunisian population as suggested by numerous studies on other markers, such as HLA and Duffy (Ayed et al 2004;Hajjej et al Sellami et al 2008). Besides the fundamental report on the genetic background of the Kell blood group system, this work will be useful to expand our red blood cell panel (manufactured in our laboratory) for rare phenotypes (such as KEL:6,7).…”

Human leukocyte antigen variation among Iranian renal transplant recipients

“…Graft survival is superior in sibling pairs having both the same serologically defined HLA antigens and a nonreactive in vitro mixed lymphocyte proliferative response when compared to randomly match deceased donors treated with the same immunosuppressive drugs (6). Polymorphism in the HLA system is used as a tool for anthropological studies, as genetic distances and correspondence analysis demonstrated that the allele and haplotype distribution of class I and class II loci are racially and geographically restricted (7,8).This prompted the use of HLA class I and class II phenotype and haplotypes in different ethnic groups for the analysis of the origin, migration and the degree of admixture of populations (9). HLA gene and haplotype frequencies have been described in different racial groups (10).…”