| 1. |
- Ejsmond, Maciej J., et al.
(author)
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Adaptive immune response selects for postponed maturation and increased body size
- 2023
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In: Functional Ecology. - : John Wiley & Sons. - 0269-8463 .- 1365-2435. ; 37:11, s. 2883-2894
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Journal article (peer-reviewed)abstract
- The Major Histocompatibility Complex (MHC) genes encode proteins that initiate the adaptive immune response by presenting pathogen-derived antigenic peptides to T lymphocytes. Host–pathogen coevolution drives MHC polymorphism, introducing intraspecific variation in host life expectancy. This variation interacts with optimal growth strategy, as growth increases reproductive potential. While mortality rate and body size-dependent fecundity are major factors shaping life histories, the effect of intraspecific variation in MHC-based immunity on the evolution of growth strategies and host body size remains unknown.Here, we model how host MHC–pathogen coevolution—and its concomitant impact on host mortality—can affect the evolution of host life histories, as represented by age at maturation and body size. Life histories were compared in scenarios with and without adaptive immune response under equal population-level mortality rates.We show that host–pathogen coevolutionary dynamics selects for postponed maturation and increased body size. Although MHC genes and genes that determine body size were physically unlinked, selection imposed by the Red Queen process generated linkage disequilibrium between immunocompetent MHC alleles and the maturation-postponing alleles that prolong growth phase and increase body size. Particularly large body size was attained when pathogens mutated slowly, thus allowing the advantage of resistant MHC alleles to persist over multiple generations.The emergence of adaptive immunity, which is pathogen-specific and enables immunological memory, is considered a major evolutionary innovation of vertebrates. Our work suggests that the adaptive immune response, mediated by polymorphic MHC genes, may drive the evolution of host body size. This form of adaptive immunity may have thus predisposed vertebrates to evolve large body size and exhibit the macroevolutionary patterns of increasing body size over time that have been detected in comparative studies.
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| 2. |
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| 3. |
- Fijarczyk, Anna, et al.
(author)
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Nuclear and mitochondrial phylogeography of the European fire‐bellied toads Bombina bombina and Bombina variegata supports their independent histories
- 2011
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In: Molecular Ecology. - 0962-1083 .- 1365-294X. ; 20:16, s. 3381-3398
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Journal article (peer-reviewed)abstract
- Exact location and number of glacial refugia still remain unclear for many European cold-blooded terrestrial vertebrates. We performed a fine-scaled multilocus phylogeographic analysis of two Bombina species combining mitochondrial variation of 950 toads from 385 sites and nuclear genes (Rag-1, Ncx-1) from a subset of samples to reconstruct their colonization and contemporary variation patterns. We identified the lowlands northwest of the Black Sea and the Carpathians to be important refugial areas for B. bombina and B. variegata,respectively. This result emphasizes the importance of Central European refugia for ectothermic terrestrial species, far north of the Mediterranean areas regarded as exclusive glacial refugia for the animals. Additional refugia for B. variegata have been located in the southern Apennines and Balkans. In contrast, no evidence for the importance of other east European plains as refugial regions has been found. The distribution of mtDNA and Ncx-1 variation suggests the presence of local refugia near the Black Sea for B. bombina; however, coalescent simulations did not allow to distinguish whether one or two refugia were present in the region. Strong genetic drift apparently accompanied postglacial expansions reducing diversity in the colonization areas. Extended sampling, coupled with the multilocus isolation with migration analysis, revealed a limited and geographically restricted gene flow from the Balkan to Carpathian populations ofB. variegata. However, despite proximity of inferred B. bombina and B. variegata refugia, gene exchange between them was not detected.
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| 4. |
- Herczeg, Dávid, et al.
(author)
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Genomic analysis reveals complex population structure within the smooth newt, Lissotriton vulgaris, in Central Europe.
- 2023
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In: Ecology and Evolution. - 2045-7758. ; 13:9, s. 10478-10478
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Journal article (peer-reviewed)abstract
- Species with wide-range distributions usually display high genetic variation. This variation can be partly explained by historical lineages that were temporally isolated from each other and are back into secondary reproductive contact, and partly by local adaptations. The smooth newt ( Lissotriton vulgaris) is one of the most widely distributed amphibians species across Eurasia and forms a species complex with a partially overlapping distribution and morphology. In the present study, we explored the population genomic structure of smooth newt lineages in the Carpathian Basin (CB) relying on single-nucleotide polymorphisms. Our dataset included new and previously published data to study the secondary contact zone between lineages in the CB and also tested for the barrier effect of rivers to gene flow between these lineages. We confirmed the presence of the South L. v. vulgaris Lineage distributed in Transdanubia and we provided new distribution records of L. v. ampelensis inhabiting the eastern territories of the CB. High genetic diversity of smooth newts was observed, especially in the North Hungarian Mountains and at the interfluves of the main rivers in the South with four distinct lineages of L. v. vulgaris and one lineage of L. v. ampelensis showing a low level of admixture with the spatially closest L. v. vulgaris lineage. Moreover, admixture detected at the interfluve of the main rivers (i.e. Danube and Tisza) suggested a secondary contact zone in the area. Finally, we found that the river Danube has a very weak effect on population divergence, while the river Tisza is a geographical barrier limiting gene flow between smooth newt lineages. As the range boundaries of L. v. vulgaris and L. v. ampelensis in the CB coincide with the river Tisza, our study underpins the influence of rivers in lineage diversification.
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| 5. |
- Herdegen, Magdalena, et al.
(author)
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Heterozygosity, sexual ornament and body size in the crested newt
- 2013
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In: Journal of Zoology. - : Wiley. - 0952-8369 .- 1469-7998. ; 291:2, s. 146-153
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Journal article (peer-reviewed)abstract
- Both genome-wide heterozygosity and heterozygosity at major histocompatibility complex (MHC) genes are often associated with higher fitness. Recent theoretical work indicates that sexual ornaments may reveal information about individual heterozygosity, and that preference for such ornaments may benefit females via the increased heterozygosity of their progeny. Here, we used path analysis to investigate the direct and indirect (via body size used as an index of condition) effects of heterozygosity at six microsatellite loci and the MHC class II DAB gene on the size of a sexual ornament, the crest, in the crested newt Triturus cristatus. We found that microsatellite heterozygosity, but not MHC heterozygosity, significantly predicted male body size, and that male body size significantly predicted crest height. However, there was no direct effect of MHC or microsatellite heterozygosity on crest height. Furthermore, microsatellite heterozygosity significantly increased with age, indicating that it had a positive effect on survival. Overall, our results are consistent with the hypothesis that heterozygosity determines condition, and that variation in condition is expressed as variation in sexual ornamentation.
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| 6. |
- Nadachowska-Brzyska, Krystyna, et al.
(author)
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Interspecific hybridization increases MHC class II diversity in two sister species of newts
- 2012
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In: Molecular Ecology. - 0962-1083 .- 1365-294X. ; 21:4, s. 887-906
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Journal article (peer-reviewed)abstract
- Our understanding of the evolutionary mechanisms generating variation within the highly polymorphic major histocompatibility complex (MHC) genes remains incomplete. Assessing MHC variation across multiple populations, of recent and ancient divergence, may facilitate understanding of geographical and temporal aspects of variation. Here, we applied 454 sequencing to perform a large-scale, comprehensive analysis of MHC class II in the closely related, hybridizing newts, Lissotriton vulgaris (Lv) and Lissotriton montandoni (Lm). Our study revealed an extensive (299 alleles) geographically structured polymorphism. Populations at the southern margin of the Lvdistribution, inhabited by old and distinct lineages (southern Lv), exhibited moderate MHC variation and strong population structure, indicating little gene flow or extensive local adaptation. Lissotriton vulgaris in central Europe and the northern Balkans (northern Lv) and almost all Lm populations had a high MHC variation. A much higher proportion of MHC alleles was shared between Lm and northern Lvthan between Lm and southern Lv. Strikingly, the average pairwise FST between northern Lv and Lm was significantly lower than between northern and southern Lv for MHC, but not for microsatellites. Thus, high MHC variation in Lm and northern Lv may result from gene flow between species. We hypothesize that the interspecific exchange of MHC genes may be facilitated by frequency-dependent selection. A marginally significant correlation between the MHC and microsatellite allelic richness indicates that demographic factors may have contributed to the present-day pattern of MHC variation, but unequivocal signatures of adaptive evolution in MHC class II sequences emphasize the role of selection on a longer timescale.
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| 7. |
- Nadachowska, Krystyna, et al.
(author)
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Characterization of microsatellite loci in the Carpathian newt (Lissotriton montandoni)
- 2010
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In: Herpetological Journal. - 0268-0130. ; 20:2, s. 107-110
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Journal article (peer-reviewed)abstract
- Seven polymorphic microsatellite loci were developed for the Carpathian newt (Lissotriton montandoni) and tested for cross-amplification in multiple geographic groups of its sister species L. vulgaris. Genetic variation was characterized for 52 L. montandoni from two sites from Poland and Romania, reflecting the geographic range of the species. The number of alleles per locus ranged from six to 13 and the observed heterozygosity ranged from 0.20 to 0.87. Significant excess of homozygotes detected at two loci may suggest the presence of null alleles. No evidence for linkage disequilibrium between loci was detected. The cross-amplification success was variable, suggesting that the use of the markers developed in the present study may be limited to geographically restricted groups of the smooth newt.
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| 8. |
- Nadachowska, Krystyna, et al.
(author)
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Divergence in the face of gene flow : the case of two newts (Amphibia: Salamandridae)
- 2009
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In: Molecular biology and evolution. - : Oxford University Press (OUP). - 0737-4038 .- 1537-1719. ; 26:4, s. 829-841
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Journal article (peer-reviewed)abstract
- Understanding the process of divergence requires the quantitative characterization of patterns of gene flow between diverging taxa. New and powerful coalescent-based methods give insight into these processes in unprecedented details by enabling the reconstruction of the temporal distribution of past gene flow. Here, we use sequence variation at eight nuclear markers and mitochondrial DNA (mtDNA) in multiple populations to study diversity, divergence, and gene flow between two subspecies of a salamander, the smooth newt (Lissotriton vulgaris kosswigi and Lissotriton vulgaris vulgaris) in Turkey. The ranges of both subspecies encompass mainly the areas of this important glacial refugial area. Populations in refugia where species have been present for a long time and differentiated in situ should better preserve the record of past gene flow than young populations in postglacial expansion areas. Sequence diversity in both subspecies was substantial (nuclear πsil = 0.69% and 1.31%). We detected long-term demographic stability in these refugial populations with large effective population sizes (Ne) of the order of 1.5–3 × 105 individuals. Gene trees and the isolation with migration (IM) analysis complemented by tests of nested IM models showed that despite deep, pre-Pleistocene divergence of the studied newts, asymmetric introgression from vulgaristo kosswigi has occurred, with signatures of recent gene flow in mtDNA and an anonymous nuclear marker, and evidence for more ancient introgression in nuclear introns. The distribution of migration times raises the intriguing possibility that even the initial divergence may have occurred in the face of gene flow.
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| 9. |
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| 10. |
- Radwan, Jacek, et al.
(author)
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MHC diversity, malaria and lifetime reproductive success in collared flycatchers
- 2012
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In: Molecular Ecology. - 0962-1083 .- 1365-294X. ; 21:10, s. 2469-2479
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Journal article (peer-reviewed)abstract
- Major histocompatibility complex (MHC) genes encode proteins involved in the recognition of parasite-derived antigens. Their extreme polymorphism is presumed to be driven by co-evolution with parasites. Hostparasite co-evolution was also hypothesized to optimize within-individual MHC diversity at the intermediate level. Here, we use unique data on lifetime reproductive success (LRS) of female collared flycatchers to test whether LRS is associated with within-individual MHC class II diversity. We also examined the association between MHC and infection with avian malaria. Using 454 sequencing, we found that individual flycatchers carry between 3 and 23 functional MHC class II B alleles. Predictions of the optimality hypothesis were not confirmed by our data as the prevalence of blood parasites decreased with functional MHC diversity. Furthermore, we did not find evidence for an association between MHC diversity and LRS.
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| 11. |
- Zagalska-Neubauer, Magdalena, et al.
(author)
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454 sequencing reveals extreme complexity of the class II Major Histocompatibility Complex in the collared flycatcher
- 2010
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In: BMC Evolutionary Biology. - : Springer Science and Business Media LLC. - 1471-2148. ; 10:1, s. 395-
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Journal article (peer-reviewed)abstract
- Background: Because of their functional significance, the Major Histocompatibility Complex (MHC) class I and II genes have been the subject of continuous interest in the fields of ecology, evolution and conservation. In some vertebrate groups MHC consists of multiple loci with similar alleles; therefore, the multiple loci must be genotyped simultaneously. In such complex systems, understanding of the evolutionary patterns and their causes has been limited due to challenges posed by genotyping. Results: Here we used 454 amplicon sequencing to characterize MHC class IIB exon 2 variation in the collared flycatcher, an important organism in evolutionary and immuno-ecological studies. On the basis of over 152,000 sequencing reads we identified 194 putative alleles in 237 individuals. We found an extreme complexity of the MHC class IIB in the collared flycatchers, with our estimates pointing to the presence of at least nine expressed loci and a large, though difficult to estimate precisely, number of pseudogene loci. Many similar alleles occurred in the pseudogenes indicating either a series of recent duplications or extensive concerted evolution. The expressed alleles showed unambiguous signals of historical selection and the occurrence of apparent interlocus exchange of alleles. Placing the collared flycatcher's MHC sequences in the context of passerine diversity revealed transspecific MHC class II evolution within the Muscicapidae family. Conclusions: 454 amplicon sequencing is an effective tool for advancing our understanding of the MHC class II structure and evolutionary patterns in Passeriformes. We found a highly dynamic pattern of evolution of MHC class IIB genes with strong signals of selection and pronounced sequence divergence in expressed genes, in contrast to the apparent sequence homogenization in pseudogenes. We show that next generation sequencing offers a universal, affordable method for the characterization and, in perspective, genotyping of MHC systems of virtually any complexity.
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