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Mateusz Buczek
Faculty of Biology and Earth Sciences, Jagiellonian University
Institute of Environmental Sciences
Poland

Antler quality in red deer: a test of Hamilton and Zuk hypothesis

poster 

Author(s): Buczek, M, Radwan, J, Okarma, H

Summary:

The evolution and maintenance of elaborate secondary sexual traits in males has been the subject of intense interest since Darwin. Hamilton and Zuk (1982) hypothesis of parasite-mediated sexual selection suggests that genetically resistant males can afford to invest more in costly ornaments. Therefore elaborated sexual traits can serve as honest indicators of male health and parasite load. We study the association between the MHC (Major Histocompatibility Complex) class II genes, gastro-intestinal and lung parasite burden and the development of antler (sexual ornament) in red deer (Cervus elaphus). We analyzed associations between antler elaboration (mass and 8 other measurements) and parasite burden (lung nematode larva, abomasum nematodes and fecal egg counts). We found a very complex pattern of relationships. The mass of antler was significantly affected by the lung nematode larva burden. We used 8 antler measurements to describe antler size using principal component analysis (PCA). PC1 (explaining 80% of variance in antler size) was significantly affected by lung nematodes burden and PC3 (explaining 5% of variance) by abomasum nematode burden. We will additionally present results of analyses investigating the effect of MHC genotype on parasite load.

Enrique Gonzalez Tortuero
Faculty of Biology of the Ludwig-Maximilien-University
Department Biology II
Germany

Bioinformatic analysis of amplicon sequencing data to study spatial and temporal variation in a Daphnia microparasite

poster 

Author(s): Gonzalez Tortuero, E, Rusek, J, Giessler, S, Petrusek, A, Wolinska, J

Summary:

Caullerya mesnili (Opisthokonta, Ichthyosporea) is an endoparasite infecting Daphnia (Crustacea, Cladocera) gut. This protozoan has high virulence and a strong genetic specificity for the infection, thus it seems to be a good model to study host-parasite coevolution dynamics. However, little is known about population structure of this microparasite. Previous work based on cloned sequences has shown that variation of the ITS region (internal transcribed spacer of ribosomal DNA) can be used to analyse spatial and temporal variation in C. mesnili. However, high-throughput next generation sequencing (NGS) allows much larger scale analyses. In this work we will present a bioinformatic pipeline analysing 392 bp long ITS amplicons from Caullerya obtained from 454 pyrosequencing. With this approach, it is possible to study in detail aspects such as the spatio-temporal distribution of Caullerya in different host populations or clones. We will also demonstrate the comparison of patterns obtained by cloning with the NGS approach.

Nellie Konijnendijk
KU Leuven
Belgium

Can differential gene expression explain differential host resistance?

poster 

Author(s): Konijnendijk, N, Raeymaekers, J, Howes, T, Milan, M, Volckaert, F

Summary:

Our ability to find signatures of selection in the genome is rapidly increasing. As a consequence we now know that strong selection leading to local adaptation can affect many regions in the genome. However, not all local adaptations result in structural gene changes. Changes in regulation of existing genes might be at least as important. To what extend this happens and whether selection only affects genes directly related to the focal trait, or also other gene classes is for many cases unknown. Host-parasite systems are very suitable for testing the importance of gene expression alterations in local adaptation. Selection is often strong due to the fact that parasites can have a big impact of fitness of the individual, making it probable we can pick up alterations in expression. Start and finish of changes in gene expression are much easier to predict than for many other (somatic) traits and temporal an spatial fluctuations in parasite abundance are common in nature, which may favor changes in gene expression rather than genetic changes as they are much easier to reverse. We used the F2 generation of two populations of stickleback fish that differ in host resistance, in order to identify which genes are involved in resistance and to understand whether heritable differences in resistance across populations are linked to differential gene expression. We infected naive fish with Gyrodactylus gasterostei, a parasitic flatworm and tracked the infection by counting parasites on the skin over time. Targeting the beginning and peak of the infection, we used microarrays to identify differential gene expression across the genome. We will present whether differences in host resistance result in differential expression patterns among populations and whether infection only affects immune related genes or a wider set of genes, thereby contributing to a better understanding of the role of gene expression alterations in host adaptation to parasites.

Sabine Giessler
Ludwig-Maximilians-University Munich
Department Biologie II
Germany

Capturing the population structure of microparasites: using ITS-sequence data and a pooled DNA approach

poster 

Author(s): Giessler, S, Wolinska, J

Summary:

The internal transcribed spacer (ITS) region of nuclear ribosomal DNA is a central target not only for molecular identification of different taxa and strains but also for analyses of population structure of wild microparasite communities. Importantly, the multi-copy nature of this region allows for successful amplification of low quantity samples of the target DNA, a common problem in studies on unicellular, unculturable microparasites. We analysed ITS-sequences from the protozoan parasite Caullerya mesnili (class Ichthyosporea) infecting waterflea (Daphnia) hosts, across several host population samples. We showed that analysing representative ITS-types (as identified by statistical parsimony networks) is a suitable method to address relevant polymorphism. The spatial patterns were consistent regardless of whether parasite DNA was extracted from individual hosts or pooled host samples. Remarkably, the efficiency to detect different sequence types was even higher after sample pooling. As shown by simulations, an easily manageable number of sequences from pooled DNA samples was already sufficient to resolve the spatial population structure in this system. In summary, the ITS-region analysed from pooled DNA samples can provide valuable insights into the spatial and temporal dynamics of microparasites. Moreover, for the analysis of sequence variation in multi-copy gene regions, the application of statistical parsimony network analysis is clearly advantageous.

Christoph Kurze
Martin-Luther-University Halle-Wittenberg
Institute of Biology
Germany

Cell sacrifice in the gut: an adaptive response towards Nosema spp. infection in honey bees

poster 

Author(s): Kurze, C, Huang, Q, Moritz, RFA

Summary:

The microsporidian Nosema ceranae is a natural parasite of the Asian honeybee Apis cerana but is now also a widespread cause of Nosemosis in the European honey bee A. mellifera. N. cerana infections can have severe effects on honey bee fitness at the individual and colony level. We found that the extensive breeding effort by Danish beekeepers against the native microsporidian parasite N. apis has produced a Nosema tolerant honey bee strain, which revealed a strongly up-regulated immune response when challenged by N. cerana infection compared to an unselected strain. After transmission via the fecal-oral route, spores normally germinate in the midgut, where they penetrate, replicate and destroy the cells of the gut epithelium. To understand the effect of the altered immune response on the level of infestation and destruction of the midgut epithelium, we compare sections between the selected and an unselected strain over the course of infection. We discuss these results in the context of an adaptive immune response and other underlying biological mechanisms of the selected strain against N. ceranae infection.

Meriem Belheouane
Max Planck Institute for evolutionary biology, Plon, Germany
Evolutionary genetics
Germany

Characterization of candidate genes from a QTL analysis of the skin microbiota in house mice

poster 

Author(s): Belheouane, M, Ibrahim, S, Baines, JF

Summary:

Meriem BELHEOUANE1,2, Saleh IBRAHIM3 and John F. BAINES1,2 1Institute for Experimental Medicine, Christian-Albrechts-University of Kiel, Germany 2Max Planck Institute for Evolutionary Biology, Plön, Germany 3Department of Dermatology, University of Lübeck, Lübeck, Germany

The skin is a complex ecosystem inhabited by diverse microbial communities, and various factors including host genetics, immune status and the environment influence community structure and diversity over space and time. Several skin diseases are postulated to have a microbial component, but little is known about the underlying mechanisms or origins of disease susceptibility. To measure the host genetic contribution to the structure and diversity of the skin microbiota and its potential contribution to disease, we performed quantitative trait locus (QTL) mapping of both autoimmune skin blistering and bacterial traits in an advanced intercross between house mouse strains derived from multiple subspecies. To understand the evolutionary origin of host genetic variability influencing both individual bacterial abundances and susceptibility to disease, we are subjecting candidate regions to more detailed molecular population genetic analysis in natural populations of house mice. In parallel, bacterial species with putative probiotic effects will be cultured and subject to genomic analysis to shed light on the role of host - commensal microbe coevolution in maintaining homeostasis of the skin community.

Sophie Gryseels
Faculty of Sciences, University of Antwerp
Department of Biology
Belgium

Contrasting evolutionary patterns in recent and deep time suggest old origins for East-African arenaviruses and strong specificity to their multimammate mouse hosts

poster 

Author(s): Gryseels, S, Baird, SJE, Makundi, R, Borremans, B, Bryjová, A, Leirs, H, Goüy de Bellocq, J

Summary:

To understand the relationship between evolutionary histories of zoonotic RNA viruses and their hosts, we study patterns of viral divergence across a host geographic range structured by both recent and ancient events. We focus on East African arenaviruses closely related to the virus causing human Lassa fever in West Africa and which infect the same natural host, the multimammate mouse Mastomys natalensis. We sampled at regular intervals along a 200 km transect in Tanzania, capturing a total of 1284 multimammate mice, of which 57 harbored arenaviruses. Multilocus microsatellite, mitochondrial and Y chromosome markers reveal a cryptic host contact zone between two M. natalensis taxa along the transect, with one admixed central locality and the surrounding 11 localities dominated by one of either taxon. The host mitochondrial lineages split about 1 million years ago and the current zone is likely the outcome of secondary contact of M. natalensis geographic isolates some thousands of years ago, driven by Holocene climate oscillations. We show that each M. natalensis taxon hosts a very distinct arenavirus, yet both arenavirus species are present in the host-admixed locality. Both hosts and viruses show further genetic differentiation within each host-taxon’s ranges, but on this level the geographic patterns of host and virus structure are not correlated. These observations suggest that recent host evolutionary history has little effect on recent arenaviral divergence (despite similar differentiation time scales), yet host-virus associations at a deeper taxonomic level have likely persisted since their shared isolation during the last glacial cycle, predating current ancestry estimates for these RNA viruses. Furthermore, if arenavirus species are unable to cross between pairs of taxonomically cryptic host sister taxa in geographic contact, a rapid arenavirus spread across M. natalensis’ pan-African range, likely home to many such cryptic taxa, seems remote.

Anna Rosanas-Urgell
Institute of Tropical Medicine
Biomedical Sciences
Belgium

Erythrocyte polymorphisms associated with protection against P. vivax malaria in Papua New Guinea children

poster 

Author(s): Rosanas-Urgell, A, Kattenberg, E, Lin, E, Robinson, L, Rarau, P, Nicolas, S, Manning, L, Moses, L, Peter, S, Ivo, M

Summary:

Malaria parasites have long coexisted with hominid ancestors: P. falciparum might had infected humans before the out-of-Africa migration and followed the human expansion throughout the tropics. This long-term interaction may have driven the co-evolution of the host-parasite and left evolutionary foot-prints in both human and parasite genomes. According to the “malaria hypothesis”, the high frequencies of deleterious mutations of some human populations are probably due to the strong selective pressure of malaria A remarkable range of polymorphisms have been associated with protection against malaria.Populations of the South West Pacific, a co-endemic region for all four human malaria parasite species, are highly diverse and exhibit a range of unique red blood cell polymorphisms, with geographical patterns paralleling malaria endemicity. We conducted three independent studies in the Madang area of Papua New Guinea to analyse the association of South East Asian Ovalocytosis (SAO) (caused by band 3 deletion SLC4A1∆27) and Gerbich negative blood group (caused by a deletion in exon3 of the glycophorin C gene (GYPC)), with protection against P. vivax malaria, testing the hypothesis that P. vivax malaria contributed to the selection of those polymorphisms. Our results showed that SAO was associated with a 46% reduction in risk of clinical P. vivax episodes in a cohort of infants 3-21 months and a 52-55% reduction in P. vivax reinfection in children 5-14 yrs. A case-control study of children 0.5–14 yrs revealed the potential for a strong protection against severe P. vivax malaria. Analysis of Gerbich blood group variants in a cohort of children 1-3 yrs showed that GYPC homozygote is associated with strong protection against P. vivax malaria and that the strength of protection increases with parasitemia. This strongly suggest that P. vivax malaria may have contributed to shaping the unique host genetic adaptations to malaria in Asian and Pacific populations.

Kathrin Näpflin
Institute of Integrative Biology ETH Zurich
Switzerland

Evasion or suppression? Infection strategies of a trypanosome gut parasite of bumblebees

poster 

Author(s): Näpflin, K

Summary:

Parasites can either avoid host detection (evasion) or actively suppress host immune responses (suppression) in order to infect their hosts. These two strategies could have important consequences for multiple infections. Evasion would not be beneficial in mixed infection if the co-infecting strain fails to also evade, but immune suppression would benefit both infecting strains irrespective of the other co-infecting strain’s strategy. Co-infection, in turn, provides the opportunity for both parasite competition and sexual recombination. The bumblebee Bombus terrestris is commonly infected by multiple strains of the trypanosome gut parasite Crithidia bombi in nature. We tested whether successful infection is achieved by suppressing or evading the host’s immune system by experimentally infecting workers of several colonies with Crithidia strains that were either highly or lowly infective. We used both single and mixed inocula of C. bombi clones, where mixed infections consisted of pairings between a highly and a lowly infective strain. We measured host gene expression of 27 candidate genes and quantified infection intensities within the same individual 18 hours post infection. We discuss implications and insights into the complex genetics of host-parasite interactions.

Cassandra Marinosci
ISEM, UMR 5554
Diversity
France

Experimental adaptation of the phytophagous spider mite, Tetranychus urticae to a new host plant

poster 

Author(s): Marinosci, C, Devaux, C, Olivieri, I

Summary:

Our ultimate goal is to identify the underlying genetic mechanisms of adaptation of phytophagous mites, Tetranychus urticae, to tomato plants, i.e. a new host species. For this purpose, we transferred in replicate lines on tomato plants individuals from two experimental groups consisting of independent ancestral populations previously maintained for four hundred generations on cucumber and bean plants. For each of the four (two ancestral and two evolved) treatments we measured on tomato leaves individual changes in life-history traits after 25 generations and then calculated growth rates from female individual measures; an additional one-generation transfer on tomato leaves before measures allowed control of potential genotype × environment effects. After 25 generations, growth rate of individuals originating from the cucumber ancestral populations was identical between the replicate lines maintained on cucumber and those transferred on tomato plants, despite the male adult survival being higher for the latter. In contrast, growth rate was higher for individuals transferred on tomato than those maintained on bean plants, mainly due to an increase in female fecundity and a decrease in the development time of both male and female individuals transferred on tomato plants. We are now comparing these data obtained on tomato leaves to similar data measured on entire tomato plants so as to evaluate potential differences in induced-defenses between leaves and plants, and subsequent potential differences in adaptation measures.

Contacts

Chairman: Octávio S. Paulo
Tel: 00 351 217500614 direct
Tel: 00 351 217500000 ext22359
Fax: 00 351 217500028
email: mail@eseb2013.com

Address

XIV Congress of the European Society for Evolutionary Biology

Organization Team
Department of Animal Biology (DBA)
Faculty of Sciences of the University of Lisbon
P-1749-016 Lisbon
Portugal

Website

Computational Biology & Population Genomics Group 
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