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Marina di Pisa, Italy

Barbuti S.,Laboratorio Of Immunogenetica
Tissue antigens

A newly identified allele, named HLA-DRB1*13:154, differs from DRB1*13:13 by the single nucleotide substitution 227T-A at codon 47 in exon 2. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd. Source

Morelli L.,University of Sassari | Useli A.,University of Sassari | Sanna D.,University of Sassari | Barbato M.,University of Sassari | And 6 more authors.
Genetics and Molecular Research

Giara and Sarcidano are 2 of the 15 extant native Italian horse breeds with limited dispersal capability that originated from a larger number of individuals. The 2 breeds live in two distinct isolated locations on the island of Sardinia. To determine the genetic structure and evolutionary history of these 2 Sardinian breeds, the first hypervariable segment of the mitochondrial DNA (mtDNA) was sequenced and analyzed in 40 Giara and Sarcidano horses and compared with publicly available mtDNA data from 43 Old World breeds. Fourdifferent analyses, including genetic distance, analysis of molecular variance, haplotype sharing, and clustering methods, were used to study the genetic relationships between the Sardinian and other horse breeds. The analyses yielded similar results, and the FST values indicated that a high percentage of the total genetic variation was explained by between-breed differences. Consistent with their distinct phenotypes and geographic isolation, the two Sardinian breeds were shown to consist of 2 distinct gene pools that had no gene flow between them. Giara horses were clearly separated from the other breeds examined and showed traces of ancient separation from horses of other breeds that share the same mitochondrial lineage. On the other hand, the data from the Sarcidano horses fit well with variation among breeds from the Iberian Peninsula and North-West Europe: genetic relationships among Sarcidano and the other breeds are consistent with the documented history of this breed. © FUNPEC-RP. Source

Morelli L.,University of Sassari | Contu D.,Laboratorio Of Immunogenetica | Santoni F.,Center for Advanced Studies | Santoni F.,University of Geneva | And 4 more authors.

Two alternative models have been proposed to explain the spread of agriculture in Europe during the Neolithic period. The demic diffusion model postulates the spreading of farmers from the Middle East along a Southeast to Northeast axis. Conversely, the cultural diffusion model assumes transmission of agricultural techniques without substantial movements of people. Support for the demic model derives largely from the observation of frequency gradients among some genetic variants, in particular haplogroups defined by single nucleotide polymorphisms (SNPs) in the Y-chromosome. A recent network analysis of the R-M269 Y chromosome lineage has purportedly corroborated Neolithic expansion from Anatolia, the site of diffusion of agriculture. However, the data are still controversial and the analyses so far performed are prone to a number of biases. In the present study we show that the addition of a single marker, DYSA7.2, dramatically changes the shape of the R-M269 network into a topology showing a clear Western-Eastern dichotomy not consistent with a radial diffusion of people from the Middle East. We have also assessed other Y-chromosome haplogroups proposed to be markers of the Neolithic diffusion of farmers and compared their intra-lineage variation-defined by short tandem repeats (STRs)-in Anatolia and in Sardinia, the only Western population where these lineages are present at appreciable frequencies and where there is substantial archaeological and genetic evidence of pre-Neolithic human occupation. The data indicate that Sardinia does not contain a subset of the variability present in Anatolia and that the shared variability between these populations is best explained by an earlier, pre-Neolithic dispersal of haplogroups from a common ancestral gene pool. Overall, these results are consistent with the cultural diffusion and do not support the demic model of agriculture diffusion. © 2010 Morelli et al. Source

Capittini C.,Laboratorio Of Immunogenetica | Tinelli C.,Unita di Biometria | Guarene M.,Laboratorio Of Immunogenetica | Pasi A.,Laboratorio Of Immunogenetica | And 9 more authors.
Genes and Immunity

The HLA genomic structure underlines the permanence of fixed haplotypes transmitted in blocks as allelic combinations. One of the most discussed concerns is how and why such a strong linkage between HLA alleles has been maintained for so long. We hypothesized a possible KIR-driven pressure in the genesis of specific HLA-A,B haplotypes. Certain HLA-A and-B molecules are ligands for the same KIR receptors through the Bw4 binding motif spanning residues 77-83 in the a1 domain. We analyzed the HLA-A and-B genomic types of 9897 Caucasian people (3533 newborns and 6364 adults) subdividing them according to the presence/absence of the HLA-B Bw4 serological epitope. For each HLA-B Bw4-and Bw6-cross-reactive group, we evaluated the presence/absence of HLA-A ligands for KIR3DL1 (HLA-A-23, HLA-A-24, HLA-A-32) and KIR3DL2 (HLA-A-03, HLA-A-11). The frequency of HLA-A KIR ligands significantly increased moving from the HLA-B Bw4/Bw4 to the HLA-B Bw4/Bw6 and the HLA-B Bw6/Bw6 groups among both newborns and adults (Po0.0001). Here, we suggest that, when the HLA-B KIR-ligand motif is lacking, the HLA-A KIR-ligand might have a vicarious role in controlling the natural killer cell-mediated innate immune response. Basing upon this compensatory function in the engagement of KIR receptors, we hypothesize that specific HLA-A,B ancestral haplotypes were generated. © 2012 Macmillan Publishers Limited. All rights reserved. Source

Guarene M.,Laboratorio Of Immunogenetica | Capittini C.,Laboratorio Of Immunogenetica | De Silvestri A.,Unita di Biometria | Pasi A.,Laboratorio Of Immunogenetica | And 12 more authors.
BioMed Research International

We compared the immunogenetic data from 2666 patients affected by HLA-related autoimmune diseases with those from 4389 ethnically matched controls (3157 cord blood donors CBD, 1232 adult bone marrow donors BMD), to verify the appropriateness of HLA typing requests received in the past decade. The frequency of HLA-B27 phenotype was 10.50% in 724 ankylosing spondylitis, 16.80% in 125 uveitis (3.41% BMD, 4.24% CBD, P<0.0001); HLA-B51 allele was 15.57% in 212 Behçet's disease (12.91% BMD, 9.88% CBD, P<0.0001); the HLA-DRB1-rheumatoid arthritis (RA) shared epitope was 13.72% in 554 RA (10.85% BMD, 13.48% CBD, P=0.016); the carriers of almost one of HLA-DQB1 susceptibility alleles were 84.91% in 795 celiac disease (CD) and 59.37% in 256 insulin-dependent diabetes mellitus (IDDM) (46.06% in 875 CBD, 42.75% in 662 BMD P<0.0001). Overall, our results show that the HLA marker frequencies were higher in patients than controls, but lower than expected from the literature data (excluding CD and IDDM) and demonstrate that, in complex immunogenetic conditions, a substantial number of genetic analyses are redundant and inappropriate, burdening to the public health costs. For this reason, we suggest the Italian Scientific Society of Immunogenetics to establish guidelines to improve the appropriateness of typing requests. © 2013 M. Guarene et al. Source

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