Department of Biology, University of Rome Tor Vergata
Friday 3:00-3:15, 200ABC
Human Leukocyte Antigens (HLA) are crucial proteins in adaptive immunity processes. Class II HLA DQ molecules are found on specific antigen-presenting cells to present exogenous epitopes. They are heterodimers encoded by DQA1 and DQB1 genes. HLA molecules have come under recent inquiry because of their extreme polymorphic nature. This study explores the allele composition of DQ genes in apparently healthy people. The sample pertains to 107 unrelated individuals: 46 belong to Ethiopian Amhara community and 61 belonging to Oromo population. Both HLA DQA1 and DQB1 genes have been high-resolution molecularly typed (Sequence Based Typing, SBT) by direct sequencing of exons 2 and 3. The allele distribution at each locus encompasses 9 DQA1 and 7 DQB1 variants in Amhara, while 8 DQA1 and 9 DQB1 alleles pertain to Oromo. The frequencies for DQA1*0102 allele, for DQA1*0201 and for DQA1*0501 allele in Amhara are respectively 28,2%; 26% and 23,8%. These alleles are significantly present also in Oromo, where the frequencies are very close each other (22,9%; 26,2 and 20,4 respectively). Among DQB1 alleles, in both human groups the *0201, *0301, *0402 and *0501 are the leading variants. The allele compositions of Amhara and Oromo communities were compared to other worldwide populations through genetic distance analysis that highlighted how their variability might be compliant with African populations, although Ethiopian samples place themselves near the Asian cluster: it suggests the influence of Asian gene pool on the African background of these Ethiopian populations, improving the genetic information about these human groups.
This study was funded by MIUR Grant, COFIN 2006 (2006053308) to G.F. De Stefano.