caa a22 4500 467907331 CHVBK 20180406152838.0 cr unu---uuuuu 170328e20060601xx s 000 0 eng 10.1007/s00251-006-0121-6 doi (NATIONALLICENCE)springer-10.1007/s00251-006-0121-6 Isolation and characterization of a MHC class II DRB locus in the European water vole ( Arvicola terrestris ) [Elektronische Daten] [Matthew Oliver, Stuart Piertney] In so-called model species, such as human and mouse, genes of the major histocompatibility complex (MHC) are characterized by extremely high levels of polymorphism, and it is considered that such diversity is maintained by balancing selection. 'sThere is now a recognized need to expand studies into nonmodel species to examine whether high MHC diversity is mirrored in natural populations, and to determine the ecological, ethological, and evolutionary processes that underpin balancing selection. To address such issues, a necessary prerequisite is the ability to characterize diversity at a single, expressed, polymorphic MHC locus on which selection may be acting. Here, we provide the first description of allelic diversity at exon 2 of an MHC class II DRB locus in the European water vole (Arvicola terrestris), characterize variation across four natural populations, and test whether the patterns of variation are consistent with the effects of balancing selection. Using single-strand conformation polymorphism analysis and subsequent DNA sequencing of gel excisions, five DRB alleles were resolved, each with a unique amino acid sequence, among 100 individuals from four geographically distinct populations. Reverse transcription polymerase chain reaction confirmed that the alleles were products from an expressed locus. Intra-allelic amino acid differences were high (10.5-33.3%), and the nonsynonymous substitution rate exceeded the synonymous substitution rate for the functional peptide-binding region (d N:d S=3.91 and P<0.005). Phylogenetic comparison of resolved alleles with closely related homologues indicated that each allele represented a unique lineage preserved across speciation events. These results indicate that balancing selection has maintained diversity of DRB allelic lineages and amino acid function over evolutionary time scales, but may be less effective at preserving alleles in contemporary populations where stochastic microevolutionary processes may dominate. Springer-Verlag, 2006 MHC class II nationallicence Polymorphism nationallicence Evolution nationallicence Balancing selection nationallicence Arvicola nationallicence Oliver Matthew School of Biological Sciences, University of Aberdeen, Zoology Building, Tillydrone Avenue, AB24 2TZ, Aberdeen, Scotland, UK aut Piertney Stuart School of Biological Sciences, University of Aberdeen, Zoology Building, Tillydrone Avenue, AB24 2TZ, Aberdeen, Scotland, UK aut Immunogenetics Springer-Verlag 58/5-6(2006-06-01), 390-395 0093-7711 58:5-6<390 2006 58 251 https://doi.org/10.1007/s00251-006-0121-6 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00251-006-0121-6 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Oliver Matthew School of Biological Sciences, University of Aberdeen, Zoology Building, Tillydrone Avenue, AB24 2TZ, Aberdeen, Scotland, UK aut NATIONALLICENCE 700 1- Piertney Stuart School of Biological Sciences, University of Aberdeen, Zoology Building, Tillydrone Avenue, AB24 2TZ, Aberdeen, Scotland, UK aut NATIONALLICENCE 773 0- Immunogenetics Springer-Verlag 58/5-6(2006-06-01), 390-395 0093-7711 58:5-6<390 2006 58 251 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer