Article

Retracted: MHC diversity and differential exposure to pathogens in kestrels (Aves: Falconidae )

Estación Biológica de Doñana (CSIC), Pabellón de Perú, Avda. Maria Luisa s/n, 41013, Sevilla, Spain.
Molecular Ecology (Impact Factor: 5.84). 02/2010; 19(4):691-705. DOI: 10.1111/j.1365-294X.2009.04507.x
Source: PubMed

ABSTRACT Pathogen diversity is thought to drive major histocompatibility complex (MHC) polymorphism given that host's immune repertories are dependent on antigen recognition capabilities. Here, we surveyed an extensive community of pathogens (n = 35 taxa) and MHC diversity in mainland versus island subspecies of the Eurasian kestrel Falco tinnunculus and in a sympatric mainland population of the phylogenetically related lesser kestrel Falco naumanni. Insular subspecies are commonly exposed to impoverished pathogen communities whilst different species' ecologies and contrasting life-history traits may lead to different levels of pathogen exposure. Although specific host traits may explain differential particular infections, overall pathogen diversity, richness and prevalence were higher in the truly cosmopolitan, euriphagous and long-distance disperser Eurasian kestrel than in the estenophagous, steppe-specialist, philopatric but long-distance migratory lesser kestrel. Accordingly, the continental population of Eurasian kestrels displayed a higher number (64 vs. 49) as well as more divergent alleles at both MHC class I and class II loci. Detailed analyses of amino acid diversity revealed that significant differences between both species were exclusive to those functionally important codons comprising the antigen binding sites. The lowest pathogen burdens and the smallest but still quite divergent set of MHC alleles (n = 16) were found in island Eurasian kestrels, where the rates of allele fixation at MHC loci seem to have occurred faster than at neutral markers. The results presented in this study would therefore support the role of pathogen diversity and abundance in shaping patterns of genetic variation at evolutionary relevant MHC genes.

0 Followers
 · 
159 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: Local adaptation is necessary for population survival and depends on the interplay between responses to selective forces and demographic processes that introduce or retain adaptive and maladaptive attributes. Host-parasite systems are dynamic, varying in space and time, where both host and parasites must adapt to their ever-changing environment in order to survive. We investigated patterns of local adaptation in raccoon populations with varying temporal exposure to the raccoon rabies virus (RRV). RRV infects approximately 85% of the population when epizootic and has been presumed to be completely lethal once contracted; however, disease challenge experiments and varying spatial patterns of RRV spread suggest some level of immunity may exist. We first assessed patterns of local adaptation in raccoon populations along the eastern seaboard of North America by contrasting spatial patterns of neutral (microsatellite loci) and functional, major histocompatibility complex (MHC) genetic diversity and structure. We explored variation of MHC allele frequencies in light of temporal population exposure to RRV (0-60 years) and specific RRV strains in infected raccoons. Our results revealed high levels of MHC variation (66 DRB exon 2 alleles) and pronounced genetic structure relative to neutral microsatellite loci, indicative of local adaptation. We found a positive association linking MHC genetic diversity and temporal RRV exposure, but no association with susceptibility and resistance to RRV strains. These results have implications for landscape epidemiology studies seeking to predict the spread of RRV and present an example of how population demographics influence the degree to which populations adapt to local selective pressures.This article is protected by copyright. All rights reserved.
    Molecular Ecology 03/2014; 23(9). DOI:10.1111/mec.12726 · 5.84 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Rhesus macaques living in western Sichuan, China, have been separated into several isolated populations due to habitat fragmentation. Previous studies based on the neutral or nearly neutral markers (mitochondrial DNA or microsatellites) showed high levels of genetic diversity and moderate genetic differentiation in the Sichuan rhesus macaques. Variation at the major histocompatibility complex (MHC) loci is widely accepted as being maintained by balancing selection, even with a low level of neutral variability in some species. However, in small and isolated or bottlenecked populations, balancing selection may be overwhelmed by genetic drift. To estimate microevolutionary forces acting on the isolated rhesus macaque populations, we examined genetic variation at Mhc-DQB1 loci in 119 wild rhesus macaques from five geographically isolated populations in western Sichuan, China, and compared the levels of MHC variation and differentiation among populations with that previously observed at neutral microsatellite markers.
    BMC Evolutionary Biology 06/2014; 14(1):130. DOI:10.1186/1471-2148-14-130 · 3.41 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Empirical evidence is accumulating that pathogens drive selection and explain common patterns of high immune gene (major histocompatibility complex, MHC) polymorphism. While most previous studies have identified that selection has acted over large time scales on the MHC, there still is a paucity of information in mammal species that demonstrates how processes operate on MHC genes in extant generations. Here we investigated 439 striped mouse individuals (Rhabdomys pumilio), trapped across seven different locations along a climatic gradient in southern Africa. Data from a previous study, conducted in the same study system, revealed that gastro-intestinal nematode infections were higher in individuals from study sites located within wetter climates compared to those from drier ones. In order to improve our understanding about the role of parasite-driven selection on the MHC in contemporary generations we tested for population divergences based on seven neutral microsatellite markers and the MHC DRB exon II locus. If divergences exist, we wanted to know if they are influenced by the spatial variation in parasite pressure mediated by different climatic conditions along the study site transect. Our analysis revealed an extensive polymorphism of 249 different MHC alleles and isolation-by-distance showed significant correlations at the microsatellite loci but not at the MHC. Nematode pressure was lowest at the driest site (Fish River Canyon, Namibia) and specifically this population revealed the highest divergence between MHC and microsatellite loci. We conclude that spatial variation in parasite pressure can facilitate local immune gene adaptations and thus mediate interactions of directional and balancing selection shaping MHC polymorphism in contemporary generations.
    Evolutionary Ecology 11/2014; 28(6):1169-1190. DOI:10.1007/s10682-014-9731-x · 2.37 Impact Factor

Full-text

Download
95 Downloads
Available from
May 30, 2014