@article{NguyenMamonekeneVateretal.2020, author = {Nguyen, Manh Duy Linh and Mamonekene, Victor and Vater, Marianne and Bartsch, Peter and Tiedemann, Ralph and Kirschbaum, Frank}, title = {Ontogeny of electric organ and electric organ discharge in Campylomormyrus rhynchophorus (Teleostei: Mormyridae)}, series = {Journal of comparative physiology; A, Neuroethology, sensory, neural, and behavioral physiology}, volume = {206}, journal = {Journal of comparative physiology; A, Neuroethology, sensory, neural, and behavioral physiology}, number = {3}, publisher = {Springer}, address = {Berlin ; Heidelberg}, issn = {0340-7594}, doi = {10.1007/s00359-020-01411-z}, pages = {453 -- 466}, year = {2020}, abstract = {The aim of this study was a longitudinal description of the ontogeny of the adult electric organ of Campylomormyrus rhynchophorus which produces as adult an electric organ discharge of very long duration (ca. 25 ms). We could indeed show (for the first time in a mormyrid fish) that the electric organ discharge which is first produced early during ontogeny in 33-mm-long juveniles is much shorter in duration and has a different shape than the electric organ discharge in 15-cm-long adults. The change from this juvenile electric organ discharges into the adult electric organ discharge takes at least a year. The increase in electric organ discharge duration could be causally linked to the development of surface evaginations, papillae, at the rostral face of the electrocyte which are recognizable for the first time in 65-mm-long juveniles and are most prominent at the periphery of the electrocyte.}, language = {en} } @article{TomowskiLozadaGobilardJeltschetal.2023, author = {Tomowski, Maxi and Lozada-Gobilard, Sissi Donna and Jeltsch, Florian and Tiedemann, Ralph}, title = {Recruitment and migration patterns reveal a key role for seed banks in the meta-population dynamics of an aquatic plant}, series = {Scientific reports}, volume = {13}, journal = {Scientific reports}, number = {1}, publisher = {Springer Nature}, address = {London}, issn = {2045-2322}, doi = {10.1038/s41598-023-37974-5}, pages = {16}, year = {2023}, abstract = {Progressive habitat fragmentation threatens plant species with narrow habitat requirements. While local environmental conditions define population growth rates and recruitment success at the patch level, dispersal is critical for population viability at the landscape scale. Identifying the dynamics of plant meta-populations is often confounded by the uncertainty about soil-stored population compartments. We combined a landscape-scale assessment of an amphibious plant's population structure with measurements of dispersal complexity in time to track dispersal and putative shifts in functional connectivity. Using 13 microsatellite markers, we analyzed the genetic structure of extant Oenanthe aquatica populations and their soil seed banks in a kettle hole system to uncover hidden connectivity among populations in time and space. Considerable spatial genetic structure and isolation-by-distance suggest limited gene flow between sites. Spatial isolation and patch size showed minor effects on genetic diversity. Genetic similarity found among extant populations and their seed banks suggests increased local recruitment, despite some evidence of migration and recent colonization. Results indicate stepping-stone dispersal across adjacent populations. Among permanent and ephemeral demes the resulting meta-population demography could be determined by source-sink dynamics. Overall, these spatiotemporal connectivity patterns support mainland-island dynamics in our system, highlighting the importance of persistent seed banks as enduring sources of genetic diversity.}, language = {en} } @article{KorniienkoNguyenBaumgartneretal.2020, author = {Korniienko, Yevheniia and Nguyen, Linh and Baumgartner, Stephanie and Vater, Marianne and Tiedemann, Ralph and Kirschbaum, Frank}, title = {Intragenus F1-hybrids of African weakly electric fish (Mormyridae: Campylomormyrus tamandua male x C. compressirostris female) are fertile}, series = {Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology}, volume = {206}, journal = {Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology}, number = {4}, publisher = {Springer}, address = {Heidelberg}, issn = {0340-7594}, doi = {10.1007/s00359-020-01425-7}, pages = {571 -- 585}, year = {2020}, abstract = {Hybridization is widespread in fish and constitutes an important mechanism in fish speciation. There is, however, little knowledge about hybridization in mormyrids. F1-interspecies hybrids betweenCampylomormyrus tamandua male x C. compressirostris female were investigated concerning: (1) fertility; (2) survival of F2-fish and (3) new gene combinations in the F2-generation concerning the structure of the electric organ and features of the electric organ discharge. These F1-hybrids achieved sexual maturity at about 12-13.5 cm total length. A breeding group comprising six males and 13 females spawned 28 times naturally proving these F1-fish to be fertile. On average 228 eggs were spawned, the average fertilization rate was 47.8\%. Eggs started to hatch 70-72 h after fertilization, average hatching rate was 95.6\%. Average mortality rate during embryonic development amounted to 2.3\%. Average malformation rate during the free embryonic stage was 27.7\%. Exogenous feeding started on day 11. In total, we raised 353 normally developed larvae all of which died consecutively, the oldest specimen reaching an age of 5 months. During survival, the activities of the larval and adult electric organs were recorded and the structure of the adult electric organ was investigated histologically.}, language = {en} } @article{ChengDennisOsuohaetal.2023, author = {Cheng, Feng and Dennis, Alice B. and Osuoha, Josephine Ijeoma and Canitz, Julia and Kirschbaum, Frank and Tiedemann, Ralph}, title = {A new genome assembly of an African weakly electric fish (Campylomormyrus compressirostris, Mormyridae) indicates rapid gene family evolution in Osteoglossomorpha}, series = {BMC genomics}, volume = {24}, journal = {BMC genomics}, number = {1}, publisher = {BMC}, address = {London}, issn = {1471-2164}, doi = {10.1186/s12864-023-09196-6}, pages = {13}, year = {2023}, abstract = {Background Teleost fishes comprise more than half of the vertebrate species. Within teleosts, most phylogenies consider the split between Osteoglossomorpha and Euteleosteomorpha/Otomorpha as basal, preceded only by the derivation of the most primitive group of teleosts, the Elopomorpha. While Osteoglossomorpha are generally species poor, the taxon contains the African weakly electric fish (Mormyroidei), which have radiated into numerous species. Within the mormyrids, the genus Campylomormyrus is mostly endemic to the Congo Basin. Campylomormyrus serves as a model to understand mechanisms of adaptive radiation and ecological speciation, especially with regard to its highly diverse species-specific electric organ discharges (EOD). Currently, there are few well-annotated genomes available for electric fish in general and mormyrids in particular. Our study aims at producing a high-quality genome assembly and to use this to examine genome evolution in relation to other teleosts. This will facilitate further understanding of the evolution of the osteoglossomorpha fish in general and of electric fish in particular. Results A high-quality weakly electric fish (C. compressirostris) genome was produced from a single individual with a genome size of 862 Mb, consisting of 1,497 contigs with an N50 of 1,399 kb and a GC-content of 43.69\%. Gene predictions identified 34,492 protein-coding genes, which is a higher number than in the two other available Osteoglossomorpha genomes of Paramormyrops kingsleyae and Scleropages formosus. A Computational Analysis of gene Family Evolution (CAFE5) comparing 33 teleost fish genomes suggests an overall faster gene family turnover rate in Osteoglossomorpha than in Otomorpha and Euteleosteomorpha. Moreover, the ratios of expanded/contracted gene family numbers in Osteoglossomorpha are significantly higher than in the other two taxa, except for species that had undergone an additional genome duplication (Cyprinus carpio and Oncorhynchus mykiss). As potassium channel proteins are hypothesized to play a key role in EOD diversity among species, we put a special focus on them, and manually curated 16 Kv1 genes. We identified a tandem duplication in the KCNA7a gene in the genome of C. compressirostris. Conclusions We present the fourth genome of an electric fish and the third well-annotated genome for Osteoglossomorpha, enabling us to compare gene family evolution among major teleost lineages. Osteoglossomorpha appear to exhibit rapid gene family evolution, with more gene family expansions than contractions. The curated Kv1 gene family showed seven gene clusters, which is more than in other analyzed fish genomes outside Osteoglossomorpha. The KCNA7a, encoding for a potassium channel central for EOD production and modulation, is tandemly duplicated which may related to the diverse EOD observed among Campylomormyrus species.}, language = {en} } @article{RomeroMujalliRochowKahletal.2021, author = {Romero Mujalli, Daniel and Rochow, Markus and Kahl, Sandra and Paraskevopoulou, Sofia and Folkertsma, Remco and Jeltsch, Florian and Tiedemann, Ralph}, title = {Adaptive and nonadaptive plasticity in changing environments}, series = {Ecology and evolution}, volume = {11}, journal = {Ecology and evolution}, number = {11}, publisher = {John Wiley \& Sons, Inc.}, address = {New Jersey}, issn = {2045-7758}, doi = {10.1002/ece3.7485}, pages = {6341 -- 6357}, year = {2021}, abstract = {Populations adapt to novel environmental conditions by genetic changes or phenotypic plasticity. Plastic responses are generally faster and can buffer fitness losses under variable conditions. Plasticity is typically modeled as random noise and linear reaction norms that assume simple one-to- one genotype-phenotype maps and no limits to the phenotypic response. Most studies on plasticity have focused on its effect on population viability. However, it is not clear, whether the advantage of plasticity depends solely on environmental fluctuations or also on the genetic and demographic properties (life histories) of populations. Here we present an individual-based model and study the relative importance of adaptive and nonadaptive plasticity for populations of sexual species with different life histories experiencing directional stochastic climate change. Environmental fluctuations were simulated using differentially autocorrelated climatic stochasticity or noise color, and scenarios of directiona climate change. Nonadaptive plasticity was simulated as a random environmental effect on trait development, while adaptive plasticity as a linear, saturating, or sinusoidal reaction norm. The last two imposed limits to the plastic response and emphasized flexible interactions of the genotype with the environment. Interestingly, this assumption led to (a) smaller phenotypic than genotypic variance in the population (many-to- one genotype-phenotype map) and the coexistence of polymorphisms, and (b) the maintenance of higher genetic variation—compared to linear reaction norms and genetic determinism—even when the population was exposed to a constant environment for several generations. Limits to plasticity led to genetic accommodation, when costs were negligible, and to the appearance of cryptic variation when limits were exceeded. We found that adaptive plasticity promoted population persistence under red environmental noise and was particularly important for life histories with low fecundity. Populations produing more offspring could cope with environmental fluctuations solely by genetic changes or random plasticity, unless environmental change was too fast.}, language = {en} }