TY - JOUR A1 - Weber, Klaus A1 - Osborn, Mary A1 - Franke, Werner W. A1 - Seib, Erinita A1 - Scheer, Ulrich A1 - Herth, Werner T1 - Identification of microtubular structures in diverse plant and animal cells by immunological cross-reaction revealed in immunofluorescence microscopy using antibodies against tubulin from porcine brain N2 - Antibody against tubulin from porcine brain was used to evaluate the immunological cross reactivity of tubulin from a variety of animal and plant cells. Indirect immunofluorescence microscopy revealed microtubule-containing structures including cytoplasmic microtubules, spindle microtubules, cilia and fIagella. Thus tubulin from diverse species of both mammals and plants show immunological cross-reactivity with tubulin from porcine brain. Results obtained by immunofluorescence microscopy are whenever possible compared with previously known ultrastructural results obtained by electron microscopy. KW - Cytologie KW - Microtubules KW - immunofluorescence KW - evolution KW - antibody KW - sperm Y1 - 1977 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-41383 ER - TY - JOUR A1 - Tomaszkiewicz, Marta A1 - Chalopin, Domitille A1 - Schartl, Manfred A1 - Galiana, Delphine A1 - Volff, Jean-Nicolas T1 - A multicopy Y-chromosomal SGNH hydrolase gene expressed in the testis of the platyfish has been captured and mobilized by a Helitron transposon JF - BMC Genetics N2 - Background: Teleost fish present a high diversity of sex determination systems, with possible frequent evolutionary turnover of sex chromosomes and sex-determining genes. In order to identify genes involved in male sex determination and differentiation in the platyfish Xiphophorus maculatus, bacterial artificial chromosome contigs from the sex-determining region differentiating the Y from the X chromosome have been assembled and analyzed. Results: A novel three-copy gene called teximY (for testis-expressed in Xiphophorus maculatus on the Y) was identified on the Y but not on the X chromosome. A highly related sequence called texim1, probably at the origin of the Y-linked genes, as well as three more divergent texim genes were detected in (pseudo) autosomal regions of the platyfish genome. Texim genes, for which no functional data are available so far in any organism, encode predicted esterases/lipases with a SGNH hydrolase domain. Texim proteins are related to proteins from very different origins, including proteins encoded by animal CR1 retrotransposons, animal platelet-activating factor acetylhydrolases (PAFah) and bacterial hydrolases. Texim gene distribution is patchy in animals. Texim sequences were detected in several fish species including killifish, medaka, pufferfish, sea bass, cod and gar, but not in zebrafish. Texim-like genes are also present in Oikopleura (urochordate), Amphioxus (cephalochordate) and sea urchin (echinoderm) but absent from mammals and other tetrapods. Interestingly, texim genes are associated with a Helitron transposon in different fish species but not in urochordates, cephalochordates and echinoderms, suggesting capture and mobilization of an ancestral texim gene in the bony fish lineage. RT-qPCR analyses showed that Y-linked teximY genes are preferentially expressed in testis, with expression at late stages of spermatogenesis (late spermatids and spermatozeugmata). Conclusions: These observations suggest either that TeximY proteins play a role in Helitron transposition in the male germ line in fish, or that texim genes are spermatogenesis genes mobilized and spread by transposable elements in fish genomes. KW - sex determination KW - testis KW - Y chromosome KW - rolling-circle transposons KW - factor acetylhydrolase activity KW - platelet activation factor KW - xiphophorus maculatus KW - oryzias-latipes KW - sequence alignment KW - DM-domain gene KW - sex-determining region KW - evolution KW - fish KW - SGNH hydrolase KW - helitron KW - transposition KW - platyfish KW - sex chromosomes Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-116746 VL - 15 IS - 44 ER - TY - JOUR A1 - Stejskal, Kerstin A1 - Streinzer, Martin A1 - Dyer, Adrian A1 - Paulus, Hannes F. A1 - Spaethe, Johannes T1 - Functional Significance of Labellum Pattern Variation in a Sexually Deceptive Orchid (Ophrys heldreichii): Evidence of Individual Signature Learning Effects JF - PLoS One N2 - Mimicking female insects to attract male pollinators is an important strategy in sexually deceptive orchids of the genus Ophrys, and some species possess flowers with conspicuous labellum patterns. The function of the variation of the patterns remains unresolved, with suggestions that these enhance pollinator communication. We investigated the possible function of the labellum pattern in Ophrys heldreichii, an orchid species in which the conspicuous and complex labellum pattern contrasts with a dark background. The orchid is pollinated exclusively by males of the solitary bee, Eucera berlandi. Comparisons of labellum patterns revealed that patterns within inflorescences are more similar than those of other conspecific plants. Field observations showed that the males approach at a great speed and directly land on flowers, but after an unsuccessful copulation attempt, bees hover close and visually scan the labellum pattern for up to a minute. Learning experiments conducted with honeybees as an accessible model of bee vision demonstrated that labellum patterns of different plants can be reliably learnt; in contrast, patterns of flowers from the same inflorescence could not be discriminated. These results support the hypothesis that variable labellum patterns in O. heldreichii are involved in flower-pollinator communication which would likely help these plants to avoid geitonogamy. KW - nectar KW - color discrimination KW - bees KW - vision KW - evolution KW - pollination KW - guides KW - honeybee KW - apis mellifera KW - insects KW - signals KW - recognize images Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-137582 VL - 10 IS - 11 ER - TY - JOUR A1 - Sieger, Charlotte Sophie A1 - Hovestadt, Thomas T1 - The degree of spatial variation relative to temporal variation influences evolution of dispersal JF - Oikos N2 - In the face of ongoing global climate and land use change, organisms have multiple possibilities to cope with the modification of their environment. The two main possibilities are to either adapt locally or disperse to a more suitable habitat. The evolution of both local adaptation and dispersal interacts and can be influenced by the spatial and temporal variation (of e.g. temperature or precipitation). In an individual based model (IBM), we explore evolution of phenotypes in landscapes with varying degree of spatial relative to global temporal variation in order to examine its influence on the evolution of dispersal, niche optimum and niche width. The relationship between temporal and spatial variation did neither influence the evolution of local adaptation in the niche optimum nor of niche widths. Dispersal probability is highly influenced by the spatio‐temporal relationship: with increasing spatial variation, dispersal probability decreases. Additionally, the shape of the distribution of the trait values over patch attributes switches from hump‐ to U‐shaped. At low spatial variance more individuals emigrate from average habitats, at high spatial variance more from extreme habitats. The comparatively high dispersal probability in extreme patches of landscapes with a high spatial variation can be explained by evolutionary succession of two kinds of adaptive response. Early in the simulations, extreme patches in landscapes with a high spatial variability act as sink habitats, where population persistence depends on highly dispersive individuals with a wide niche. With ongoing evolution, local adaptation of the remaining individuals takes over, but simultaneously a possible bet‐hedging strategy promotes higher dispersal probabilities in those habitats. Here, in generations that experience extreme shifts from the temporal mean of the patch attribute, the expected fitness becomes higher for dispersing individuals than for philopatric individuals. This means that under certain circumstances, both local adaptation and high dispersal probability can be selected for for coping with the projected environmental changes in the future. KW - bet-hedging KW - dispersal KW - ecological niche KW - evolution KW - individual based model KW - spatial variation KW - temporal variation Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-239049 VL - 129 IS - 11 SP - 1611 EP - 1622 ER - TY - JOUR A1 - Rybalka, Nataliya A1 - Wolf, Matthias A1 - Andersen, Robert A1 - Friedl, Thomas T1 - Congruence of chloroplast- and nuclear-encoded DNA sequence variations used to assess species boundaries in the soil microalga Heterococcus (Stramenopiles, Xanthophyceae) JF - BMC Evolutionary Biology N2 - Background: Heterococcus is a microalgal genus of Xanthophyceae (Stramenopiles) that is common and widespread in soils, especially from cold regions. Species are characterized by extensively branched filaments produced when grown on agarized culture medium. Despite the large number of species described exclusively using light microscopic morphology, the assessment of species diversity is hampered by extensive morphological plasticity. Results: Two independent types of molecular data, the chloroplast-encoded psbA/rbcL spacer complemented by rbcL gene and the internal transcribed spacer 2 of the nuclear rDNA cistron (ITS2), congruently recovered a robust phylogenetic structure. With ITS2 considerable sequence and secondary structure divergence existed among the eight species, but a combined sequence and secondary structure phylogenetic analysis confined to helix II of ITS2 corroborated relationships as inferred from the rbcL gene phylogeny. Intra-genomic divergence of ITS2 sequences was revealed in many strains. The 'monophyletic species concept', appropriate for microalgae without known sexual reproduction, revealed eight different species. Species boundaries established using the molecular-based monophyletic species concept were more conservative than the traditional morphological species concept. Within a species, almost identical chloroplast marker sequences (genotypes) were repeatedly recovered from strains of different origins. At least two species had widespread geographical distributions; however, within a given species, genotypes recovered from Antarctic strains were distinct from those in temperate habitats. Furthermore, the sequence diversity may correspond to adaptation to different types of habitats or climates. Conclusions: We established a method and a reference data base for the unambiguous identification of species of the common soil microalgal genus Heterococcus which uses DNA sequence variation in markers from plastid and nuclear genomes. The molecular data were more reliable and more conservative than morphological data. KW - xanthophyceae KW - psbA/rbcL spacer KW - ITS2 KW - tool KW - RBCL KW - alignment KW - evolution KW - chlorophyta KW - RNA secondary structure KW - terrestrial habitats KW - phylogenetic trees KW - mixed models KW - green algae KW - heterococcus KW - systematics KW - molecular phylogeny KW - species concept Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-121848 SN - 1471-2148 VL - 13 IS - 39 ER - TY - JOUR A1 - Poethke, Hans-Joachim A1 - Hovestadt, Thomas A1 - Mitesser, Oliver T1 - Local extinction and the evolution of dispersal rates: Causes and correlations N2 - We present the results of individual-based simulation experiments on the evolution of dispersal rates of organisms living in metapopulations. We find conflicting results regarding the relationship between local extinction rate and evolutionarily stable (ES) dispersal rate depending on which principal mechanism causes extinction: if extinction is caused by environmental catastrophes eradicating local populations, we observe a positive correlation between extinction and ES dispersal rate; if extinction is a consequence of stochastic local dynamics and environmental fluctuations, the correlation becomes ambiguous; and in cases where extinction is caused by dispersal mortality, a negative correlation between local extinction rate and ES dispersal rate emerges. We conclude that extinction rate, which both affects and is affected by dispersal rates, is not an ideal predictor for optimal dispersal rates. KW - Ausbreitung KW - Evolution KW - Computersimulation KW - Metapopulation KW - dispersal KW - evolution KW - ESS KW - metapopulation KW - extinction KW - individual-based model Y1 - 2003 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-47718 ER - TY - JOUR A1 - Mitesser, Oliver A1 - Weissel, Norbert A1 - Strohm, Erhard A1 - Poethke, Hans-Joachim T1 - Adaptive dynamic resource allocation in annual eusocial insects: Environmental variation will not necessarily promote graded control N2 - Background: According to the classical model of Macevicz and Oster, annual eusocial insects should show a clear dichotomous "bang-bang" strategy of resource allocation; colony fitness is maximised when a period of pure colony growth (exclusive production of workers) is followed by a single reproductive period characterised by the exclusive production of sexuals. However, in several species graded investment strategies with a simultaneous production of workers and sexuals have been observed. Such deviations from the "bang-bang" strategy are usually interpreted as an adaptive (bet-hedging) response to environmental fluctuations such as variation in season length or food availability. To generate predictions about the optimal investment pattern of insect colonies in fluctuating environments, we slightly modified Macevicz and Oster's classical model of annual colony dynamics and used a dynamic programming approach nested into a recurrence procedure for the solution of the stochastic optimal control problem. Results: 1) The optimal switching time between pure colony growth and the exclusive production of sexuals decreases with increasing environmental variance. 2) Yet, for reasonable levels of environmental fluctuations no deviation from the typical bang-bang strategy is predicted. 3) Model calculations for the halictid bee Lasioglossum malachurum reveal that bet-hedging is not likely to be the reason for the graded allocation into sexuals versus workers observed in this species. 4) When environmental variance reaches a critical level our model predicts an abrupt change from dichotomous behaviour to graded allocation strategies, but the transition between colony growth and production of sexuals is not necessarily monotonic. Both, the critical level of environmental variance as well as the characteristic pattern of resource allocation strongly depend on the type of function used to describe environmental fluctuations. Conclusion: Up to now bet-hedging as an evolutionary response to variation in season length has been the main argument to explain field observations of graded resource allocation in annual eusocial insect species. However, our model shows that the effect of moderate fluctuations of environmental conditions does not select for deviation from the classical bang-bang strategy and that the evolution of graded allocation strategies can be triggered only by extreme fluctuations. Detailed quantitative observations on resource allocation in eusocial insects are needed to analyse the relevance of alternative explanations, e.g. logistic colony growth or reproductive conflict between queen and workers, for the evolution of graded allocation strategies. KW - Insekten KW - Fitness KW - Evolution KW - Sozialität KW - resource allocation KW - fitness KW - evolution KW - eusociality KW - insect Y1 - 2007 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-45412 ER - TY - JOUR A1 - Matos, I A1 - Machado, M. P. A1 - Schartl, M. A1 - Coelho, M. M. T1 - Gene expression dosage regulation in an allopolyploid fish JF - PLoS ONE N2 - How allopolyploids are able not only to cope but profit from their condition is a question that remains elusive, but is of great importance within the context of successful allopolyploid evolution. One outstanding example of successful allopolyploidy is the endemic Iberian cyprinid Squalius alburnoides. Previously, based on the evaluation of a few genes, it was reported that the transcription levels between diploid and triploid S. alburnoides were similar. If this phenomenon occurs on a full genomic scale, a wide functional "diploidization'' could be related to the success of these polyploids. We generated RNA-seq data from whole juvenile fish and from adult livers, to perform the first comparative quantitative transcriptomic analysis between diploid and triploid individuals of a vertebrate allopolyploid. Together with an assay to estimate relative expression per cell, it was possible to infer the relative sizes of transcriptomes. This showed that diploid and triploid S. alburnoides hybrids have similar liver transcriptome sizes. This in turn made it valid to directly compare the S. alburnoides RNA-seq transcript data sets and obtain a profile of dosage responses across the S. alburnoides transcriptome. We found that 64% of transcripts in juveniles' samples and 44% in liver samples differed less than twofold between diploid and triploid hybrids (similar expression). Yet, respectively 29% and 15% of transcripts presented accurate dosage compensation (PAA/PA expression ratio of 1 instead of 1.5). Therefore, an exact functional diploidization of the triploid genome does not occur, but a significant down regulation of gene expression in triploids was observed. However, for those genes with similar expression levels between diploids and triploids, expression is not globally strictly proportional to gene dosage nor is it set to a perfect diploid level. This quantitative expression flexibility may be a strong contributor to overcome the genomic shock, and be an immediate evolutionary advantage of allopolyploids. KW - RNA-Seq KW - balance hypothesis KW - hybrids KW - genome KW - maize KW - Squalius alburnoides KW - cell size KW - evolution KW - heterosis KW - complex Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-143565 VL - 10 IS - 3 ER - TY - JOUR A1 - Kang, Ji Hyoun A1 - Schartl, Manfred A1 - Walter, Ronald B. A1 - Meyer, Axel T1 - Comprehensive phylogenetic analysis of all species of swordtails and platies (Pisces: Genus Xiphophorus) uncovers a hybrid origin of a swordtail fish, Xiphophorus monticolus, and demonstrates that the sexually selected sword originated in the ancestral lineage of the genus, but was lost again secondarily JF - BMC Evolutionary Biology N2 - Background: Males in some species of the genus Xiphophorus, small freshwater fishes from Meso-America, have an extended caudal fin, or sword - hence their common name "swordtails". Longer swords are preferred by females from both sworded and - surprisingly also, non-sworded (platyfish) species that belong to the same genus. Swordtails have been studied widely as models in research on sexual selection. Specifically, the pre-existing bias hypothesis was interpreted to best explain the observed bias of females in presumed ancestral lineages of swordless species that show a preference for assumed derived males with swords over their conspecific swordless males. However, many of the phylogenetic relationships within this genus still remained unresolved. Here we construct a comprehensive molecular phylogeny of all 26 known Xiphophorus species, including the four recently described species (X. kallmani, X. mayae, X. mixei and X. monticolus). We use two mitochondrial and six new nuclear markers in an effort to increase the understanding of the evolutionary relationships among the species in this genus. Based on the phylogeny, the evolutionary history and character state evolution of the sword was reconstructed and found to have originated in the common ancestral lineage of the genus Xiphophorus and that it was lost again secondarily. Results: We estimated the evolutionary relationships among all known species of the genus Xiphophorus based on the largest set of DNA markers so far. The phylogeny indicates that one of the newly described swordtail species, Xiphophorus monticolus, is likely to have arisen through hybridization since it is placed with the southern platyfish in the mitochondrial phylogeny, but with the southern swordtails in the nuclear phylogeny. Such discordance between these two types of markers is a strong indication for a hybrid origin. Additionally, by using a maximum likelihood approach the possession of the sexually selected sword trait is shown to be the most likely ancestral state for the genus Xiphophorus. Further, we provide a well supported estimation of the phylogenetic relationships between the previously unresolved northern swordtail groups. Conclusions: This comprehensive molecular phylogeny of the entire genus Xiphophorus provides evidence that a second swordtail species, X. monticolus, arose through hybridization. Previously, we demonstrated that X. clemenciae, another southern swordtail species, arose via hybridization. These findings highlight the potential key role of hybridization in the evolution of this genus and suggest the need for further investigations into how hybridization contributes to speciation more generally. KW - parten-offspring conflict KW - introgressive hybridization KW - mitochondrial DNA KW - molecular phylogeny KW - likelihood approach KW - tree selection KW - preexisting bias KW - adaptive radiation KW - evolution KW - poeciliidae Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-121853 SN - 1471-2148 VL - 13 IS - 25 ER - TY - JOUR A1 - Höhne, Christin A1 - Prokopov, Dmitry A1 - Kuhl, Heiner A1 - Du, Kang A1 - Klopp, Christophe A1 - Wuertz, Sven A1 - Trifonov, Vladimir A1 - Stöck, Matthias T1 - The immune system of sturgeons and paddlefish (Acipenseriformes): a review with new data from a chromosome‐scale sturgeon genome JF - Reviews in Aquaculture N2 - Sturgeon immunity is relevant for basic evolutionary and applied research, including caviar‐ and meat‐producing aquaculture, protection of wild sturgeons and their re‐introduction through conservation aquaculture. Starting from a comprehensive overview of immune organs, we discuss pathways of innate and adaptive immune systems in a vertebrate phylogenetic and genomic context. The thymus as a key organ of adaptive immunity in sturgeons requires future molecular studies. Likewise, data on immune functions of sturgeon‐specific pericardial and meningeal tissues are largely missing. Integrating immunological and endocrine functions, the sturgeon head kidney resembles that of teleosts. Recently identified pattern recognition receptors in sturgeon require research on downstream regulation. We review first acipenseriform data on Toll‐like receptors (TLRs), type I transmembrane glycoproteins expressed in membranes and endosomes, initiating inflammation and host defence by molecular pattern‐induced activation. Retinoic acid‐inducible gene‐I‐like (RIG‐like) receptors of sturgeons present RNA and key sensors of virus infections in most cell types. Sturgeons and teleosts share major components of the adaptive immune system, including B cells, immunoglobulins, major histocompatibility complex and the adaptive cellular response by T cells. The ontogeny of the sturgeon innate and onset of adaptive immune genes in different organs remain understudied. In a genomics perspective, our new data on 100 key immune genes exemplify a multitude of evolutionary trajectories after the sturgeon‐specific genome duplication, where some single‐copy genes contrast with many duplications, allowing tissue specialization, sub‐functionalization or both. Our preliminary conclusion should be tested by future evolutionary bioinformatics, involving all >1000 immunity genes. This knowledge update about the acipenseriform immune system identifies several important research gaps and presents a basis for future applications. KW - evolution KW - genomics KW - immune genes KW - immune organs KW - immune system KW - sturgeon Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-239865 VL - 13 IS - 3 SP - 1709 EP - 1729 ER -