Immunogenetics of micromammalmacroparasite interactions

Charbonnel, Nathalie; Bellocq, Joëlle Goüy de; Morand, Sergé

doi:10.1007/978-4-431-36025-4_20

Cited by 8 publications

(8 citation statements)

References 164 publications

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“…We found no significant global co‐inertia between the genetic and parasitological matrices, but this is not surprising given the difficulties related in the literature to find MHC‐parasite associations (Hedrick & Kim, 2000). This result is not inconsistent with PMBS if: (i) some important parasites, such as bacteria or viruses, were not analysed; (ii) other genes influence parasite burden (see Charbonnel et al. , 2006 for examples of genes likely to be associated with macroparasites); (iii) various strains of parasites are different enough that different alleles might confer resistance, and the genetic diversity of parasites should be included in such studies (e.g.…”

Section: Discussionmentioning

confidence: 83%

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Multiple parasites mediate balancing selection at two MHC class II genes in the fossorial water vole: insights from multivariate analyses and population genetics

Tollenaere

Bryja

Galan

et al. 2008

J of Evolutionary Biology

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We investigated the factors mediating selection acting on two MHC class II genes (DQA and DRB) in water vole (Arvicola scherman) natural populations in the French Jura Mountains. Population genetics showed significant homogeneity in allelic frequencies at the DQA1 locus as opposed to neutral markers (nine microsatellites), indicating balancing selection acting on this gene. Moreover, almost exhaustive screening for parasites, including gastrointestinal helminths, brain coccidia and antibodies against viruses responsible for zoonoses, was carried out. We applied a co‐inertia approach to the genetic and parasitological data sets to avoid statistical problems related to multiple testing. Two alleles, Arte‐DRB‐11 and Arte‐DRB‐15, displayed antagonistic associations with the nematode Trichuris arvicolae, revealing the potential parasite‐mediated selection acting on DRB locus. Selection mechanisms acting on the two MHC class II genes thus appeared different. Moreover, overdominance as balancing selection mechanism was showed highly unlikely in this system.

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Section: Discussionmentioning

confidence: 83%

“…, 1997). DQA and DRB are the most studied MHC class II genes in small mammals (Charbonnel et al. , 2006).…”

Section: Introductionmentioning

confidence: 99%

Multiple parasites mediate balancing selection at two MHC class II genes in the fossorial water vole: insights from multivariate analyses and population genetics

Tollenaere

Bryja

Galan

et al. 2008

J of Evolutionary Biology

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“…For example, the balance between cytokines promoting Th1- and Th2-type immune responses (which are broadly effective against microparasites and macroparasites, respectively) and, in turn, the modulation of these responses by regulatory T cells, is a major factor in the outcome of the host response to infection [21] , [22] . Any genetic variants that influence this balance and the resulting immune profile of an individual are likely therefore to be a major factor in determining host susceptibility [23] , [24] . As different arms of the immune response are counter-regulated, and different types of pathogen require different effector responses [25] , cytokine variation may be particularly relevant in natural populations infected by multiple pathogen species.…”

Section: Introductionmentioning

confidence: 99%

Genetic Diversity in Cytokines Associated with Immune Variation and Resistance to Multiple Pathogens in a Natural Rodent Population

et al. 2011

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Pathogens are believed to drive genetic diversity at host loci involved in immunity to infectious disease. To date, studies exploring the genetic basis of pathogen resistance in the wild have focussed almost exclusively on genes of the Major Histocompatibility Complex (MHC); the role of genetic variation elsewhere in the genome as a basis for variation in pathogen resistance has rarely been explored in natural populations. Cytokines are signalling molecules with a role in many immunological and physiological processes. Here we use a natural population of field voles (Microtus agrestis) to examine how genetic diversity at a suite of cytokine and other immune loci impacts the immune response phenotype and resistance to several endemic pathogen species. By using linear models to first control for a range of non-genetic factors, we demonstrate strong effects of genetic variation at cytokine loci both on host immunological parameters and on resistance to multiple pathogens. These effects were primarily localized to three cytokine genes (Interleukin 1 beta (Il1b), Il2, and Il12b), rather than to other cytokines tested, or to membrane-bound, non-cytokine immune loci. The observed genetic effects were as great as for other intrinsic factors such as sex and body weight. Our results demonstrate that genetic diversity at cytokine loci is a novel and important source of individual variation in immune function and pathogen resistance in natural populations. The products of these loci are therefore likely to affect interactions between pathogens and help determine survival and reproductive success in natural populations. Our study also highlights the utility of wild rodents as a model of ecological immunology, to better understand the causes and consequences of variation in immune function in natural populations including humans.

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“…Evolutionary biologists are increasingly focusing their interest on the interplay between population dynamics and natural selection (Saccheri & Hanski 2006). Molecular markers linked to host–pathogen interactions are of great potential use for increasing our understanding of these processes (reviewed in Charbonnel et al . 2006).…”

Section: Introductionmentioning

confidence: 99%

Density‐related changes in selection pattern for major histocompatibility complex genes in fluctuating populations of voles

et al. 2007

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Host-pathogen interactions are of particular interest in studies of the interplay between population dynamics and natural selection. The major histocompatibility complex (MHC) genes of demographically fluctuating species are highly suitable markers for such studies, because they are involved in initiating the immune response against pathogens and display a high level of adaptive genetic variation. We investigated whether two MHC class II genes (DQA1, DRB) were subjected to contemporary selection during increases in the density of fossorial water vole (Arvicola terrestris) populations, by comparing the neutral genetic structure of seven populations with that estimated from MHC genes. Tests for heterozygosity excess indicated that DQA1 was subject to intense balancing selection. No such selection operated on neutral markers. This pattern of selection became more marked with increasing abundance. In the low-abundance phase, when populations were geographically isolated, both overall differentiation and isolation-by-distance were more marked for MHC genes than for neutral markers. Model-based simulations identified DQA1 as an outlier (i.e. under selection) in a single population, suggesting the action of local selection in fragmented populations. The differences between MHC and neutral markers gradually disappeared with increasing effective migration between sites. In the high-abundance year, DQA1 displayed significantly lower levels of overall differentiation than the neutral markers. This gene therefore displayed stronger homogenization than observed under drift and migration alone. The observed signs of selection were much weaker for DRB. Spatial and temporal fluctuations in parasite pressure and locus-specific selection are probably the most plausible mechanisms underlying the observed changes in selection pattern during the demographic cycle.

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Immunogenetics of micromammalmacroparasite interactions

Cited by 8 publications

References 164 publications

Multiple parasites mediate balancing selection at two MHC class II genes in the fossorial water vole: insights from multivariate analyses and population genetics

Multiple parasites mediate balancing selection at two MHC class II genes in the fossorial water vole: insights from multivariate analyses and population genetics

Genetic Diversity in Cytokines Associated with Immune Variation and Resistance to Multiple Pathogens in a Natural Rodent Population

Density‐related changes in selection pattern for major histocompatibility complex genes in fluctuating populations of voles

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