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Villegas LI, Ferretti L, Wiehe T, Waldvogel A, Schiffer PH. Parthenogenomics: Insights on mutation rates and nucleotide diversity in parthenogenetic Panagrolaimus nematodes. Ecol Evol 2024; 14:e10831. [PMID: 38192904 PMCID: PMC10771965 DOI: 10.1002/ece3.10831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 12/11/2023] [Accepted: 12/13/2023] [Indexed: 01/10/2024] Open
Abstract
Asexual reproduction is assumed to lead to the accumulation of deleterious mutations, and reduced heterozygosity due to the absence of recombination. Panagrolaimid nematode species display different modes of reproduction. Sexual reproduction with distinct males and females, asexual reproduction through parthenogenesis in the genus Panagrolaimus, and hermaphroditism in Propanagrolaimus. Here, we compared genomic features of free-living nematodes in populations and species isolated from geographically distant regions to study diversity, and genome-wide differentiation under different modes of reproduction. We firstly estimated genome-wide spontaneous mutation rates in a triploid parthenogenetic Panagrolaimus, and a diploid hermaphroditic Propanagrolaimus via long-term mutation accumulation lines. Secondly, we calculated population genetic parameters including nucleotide diversity, and fixation index (F ST) between populations of asexually and sexually reproducing nematodes. Thirdly, we used phylogenetic network methods on sexually and asexually reproducing Panagrolaimus populations to understand evolutionary relationships between them. The estimated mutation rate was slightly lower for the asexual population, as expected for taxa with this reproductive mode. Natural polyploid asexual populations revealed higher nucleotide diversity. Despite their common ancestor, a gene network revealed a high level of genetic differentiation among asexual populations. The elevated heterozygosity found in the triploid parthenogens could be explained by the third genome copy. Given their tendentially lower mutation rates it can be hypothesized that this is part of the mechanism to evade Muller's ratchet. Our findings in parthenogenetic triploid nematode populations seem to challenge common expectations of evolution under asexuality.
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Affiliation(s)
| | | | - Thomas Wiehe
- Institute for GeneticsUniversity of CologneKölnGermany
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Haider M, Schilling MP, Moest MH, Steiner FM, Schlick‐Steiner BC, Arthofer W. Evolutionary history of an Alpine Archaeognath ( Machilis pallida): Insights from different variant. Ecol Evol 2023; 13:e10227. [PMID: 37404697 PMCID: PMC10316371 DOI: 10.1002/ece3.10227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 05/31/2023] [Accepted: 06/09/2023] [Indexed: 07/06/2023] Open
Abstract
Reconstruction of species histories is a central aspect of evolutionary biology. Patterns of genetic variation within and among populations can be leveraged to elucidate evolutionary processes and demographic histories. However, interpreting genetic signatures and unraveling the contributing processes can be challenging, in particular for non-model organisms with complex reproductive modes and genome organization. One way forward is the combined consideration of patterns revealed by different molecular markers (nuclear vs. mitochondrial) and types of variants (common vs. rare) that differ in their age, mode, and rate of evolution. Here, we applied this approach to RNAseq data generated for Machilis pallida (Archaeognatha), an Alpine jumping bristletail considered parthenogenetic and triploid. We generated de novo transcriptome and mitochondrial assemblies to obtain high-density data to investigate patterns of mitochondrial and common and rare nuclear variation in 17 M. pallida individuals sampled from all known populations. We find that the different variant types capture distinct aspects of the evolutionary history and discuss the observed patterns in the context of parthenogenesis, polyploidy, and survival during glaciation. This study highlights the potential of different variant types to gain insights into evolutionary scenarios even from challenging but often available data and the suitability of M. pallida and the genus Machilis as a study system for the evolution of sexual strategies and polyploidization during environmental change. We also emphasize the need for further research which will be stimulated and facilitated by these newly generated resources and insights.
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Affiliation(s)
- Marlene Haider
- Department of Ecology, Molecular Ecology GroupUniversity of InnsbruckInnsbruckAustria
| | - Martin P. Schilling
- Department of Ecology, Molecular Ecology GroupUniversity of InnsbruckInnsbruckAustria
| | - Markus H. Moest
- Department of Ecology, Molecular Ecology GroupUniversity of InnsbruckInnsbruckAustria
| | - Florian M. Steiner
- Department of Ecology, Molecular Ecology GroupUniversity of InnsbruckInnsbruckAustria
| | | | - Wolfgang Arthofer
- Department of Ecology, Molecular Ecology GroupUniversity of InnsbruckInnsbruckAustria
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Wang P, Zhao D, Li J, Su J, Zhang C, Li S, Fan F, Dai Z, Liao X, Mao Z, Bi C, Zhang X. Artificial Diploid Escherichia coli by a CRISPR Chromosome-Doubling Technique. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2205855. [PMID: 36642845 PMCID: PMC9982549 DOI: 10.1002/advs.202205855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Revised: 12/06/2022] [Indexed: 06/17/2023]
Abstract
Synthetic biology has been represented by the creation of artificial life forms at the genomic scale. In this work, a CRISPR-based chromosome-doubling technique is designed to first construct an artificial diploid Escherichia coli cell. The stable single-cell diploid E. coli is isolated by both maximal dilution plating and flow cytometry, and confirmed with quantitative PCR, fluorescent in situ hybridization, and third-generation genome sequencing. The diploid E. coli has a greatly reduced growth rate and elongated cells at 4-5 µm. It is robust against radiation, and the survival rate after exposure to UV increased 40-fold relative to WT. As a novel life form, the artificial diploid E. coli is an ideal substrate for research fundamental questions in life science concerning polyploidy. And this technique may be applied to other bacteria.
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Affiliation(s)
- Pengju Wang
- Tianjin Institute of Industrial BiotechnologyChinese Academy of SciencesTianjin300308P. R. China
- Key Laboratory of Systems Microbial BiotechnologyChinese Academy of SciencesTianjin300308P. R. China
| | - Dongdong Zhao
- Tianjin Institute of Industrial BiotechnologyChinese Academy of SciencesTianjin300308P. R. China
- Key Laboratory of Systems Microbial BiotechnologyChinese Academy of SciencesTianjin300308P. R. China
| | - Ju Li
- College of Life ScienceTianjin Normal UniversityTianjin300382P. R. China
| | - Junchang Su
- Tianjin Institute of Industrial BiotechnologyChinese Academy of SciencesTianjin300308P. R. China
- School of Biological EngineeringDalian Polytechnic UniversityDalian116034P. R. China
| | - Chunzhi Zhang
- School of Biological EngineeringDalian Polytechnic UniversityDalian116034P. R. China
| | - Siwei Li
- Tianjin Institute of Industrial BiotechnologyChinese Academy of SciencesTianjin300308P. R. China
- Key Laboratory of Systems Microbial BiotechnologyChinese Academy of SciencesTianjin300308P. R. China
| | - Feiyu Fan
- Tianjin Institute of Industrial BiotechnologyChinese Academy of SciencesTianjin300308P. R. China
- Key Laboratory of Systems Microbial BiotechnologyChinese Academy of SciencesTianjin300308P. R. China
| | - Zhubo Dai
- Tianjin Institute of Industrial BiotechnologyChinese Academy of SciencesTianjin300308P. R. China
- Key Laboratory of Systems Microbial BiotechnologyChinese Academy of SciencesTianjin300308P. R. China
| | - Xiaoping Liao
- Tianjin Institute of Industrial BiotechnologyChinese Academy of SciencesTianjin300308P. R. China
- Biodesign CenterKey Laboratory of Systems Microbial BiotechnologyTianjin Institute of Industrial BiotechnologyChinese Academy of SciencesTianjin300308P. R. China
| | - Zhitao Mao
- Tianjin Institute of Industrial BiotechnologyChinese Academy of SciencesTianjin300308P. R. China
- Biodesign CenterKey Laboratory of Systems Microbial BiotechnologyTianjin Institute of Industrial BiotechnologyChinese Academy of SciencesTianjin300308P. R. China
| | - Changhao Bi
- Tianjin Institute of Industrial BiotechnologyChinese Academy of SciencesTianjin300308P. R. China
- Key Laboratory of Systems Microbial BiotechnologyChinese Academy of SciencesTianjin300308P. R. China
| | - Xueli Zhang
- Tianjin Institute of Industrial BiotechnologyChinese Academy of SciencesTianjin300308P. R. China
- Key Laboratory of Systems Microbial BiotechnologyChinese Academy of SciencesTianjin300308P. R. China
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Radačovská A, Čisovská Bazsalovicsová E, Šoltys K, Štefka J, Minárik G, Gustinelli A, Chugunova JK, Králová-Hromadová I. Unique genetic structure of the human tapeworm Dibothriocephalus latus from the Alpine lakes region - a successful adaptation? Parasitology 2022; 149:1106-1118. [PMID: 35570686 PMCID: PMC11010471 DOI: 10.1017/s0031182022000634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 04/22/2022] [Accepted: 04/29/2022] [Indexed: 11/07/2022]
Abstract
Dibothriocephalus latus is the most frequent causative agent of fish-borne zoonosis (diphyllobothriosis) in Europe, where it is currently circulating mainly in the Alpine lakes region (ALR) and Russia. Three mitochondrial genes (cox1, cob and nad3) and 6 microsatellite loci were analysed to determine how is the recently detected triploidy/parthenogenesis in tapeworms from ALR displayed at the DNA level. A geographically distant population from the Krasnoyarsk Reservoir in Russia (RU-KR) was analysed as a comparative population. One or 2 alleles of each microsatellite locus was detected in plerocercoids from RU-KR, corresponding to the microsatellite pattern of a diploid organism. In contrast, 1–3 alleles were observed in tapeworms from ALR, in accordance with their triploidy. The high diversity of mitochondrial haplotypes in D. latus from RU-KR implied an original and relatively stable population, but the identical structure of mitochondrial genes of tapeworms from ALR was probably a consequence of a bottleneck typical of introduced populations. These results indicated that the diploid/sexually reproducing population from RU-KR was ancestral, located within the centre of the distribution of the species, and the triploid/parthenogenetically reproducing subalpine population was at the margin of the distribution. The current study revealed the allelic structure of the microsatellite loci in the triploid tapeworm for the first time.
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Affiliation(s)
- Alžbeta Radačovská
- Institute of Parasitology, Slovak Academy of Sciences, Hlinkova 3, 04001 Košice, Slovakia
| | | | - Katarína Šoltys
- Department of Microbiology and Virology, Faculty of Natural Sciences, Comenius University in Bratislava, Ilkovičova 6, 84215 Bratislava, Slovakia
| | - Jan Štefka
- Biology Centre CAS, Institute of Parasitology, Branišovská 31, 37005 České Budějovice, Czech Republic
- Faculty of Science, University of South Bohemia, Branišovská 1760, 37005 České Budějovice, Czech Republic
| | - Gabriel Minárik
- Medirex, a.s., Galvaniho 17/C, P.O. Box 143, 82016 Bratislava, Slovakia
| | - Andrea Gustinelli
- Department of Veterinary Medical Sciences, University of Bologna, Via Tolara di Sopra 50, 40064 Ozzano Emilia, BO, Italy
| | - Julia K. Chugunova
- Krasnoyarsk Branch of the Russian Federal Research Institute of Fisheries and Oceanography ‘VNIRO’, Parizhskoi Kommuny, 33, 660097 Krasnoyarsk, Russia
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Sluys R. Biogeography and diversification of the freshwater planarian Crenobia alpina sensu lato (Platyhelminthes, Tricladida): A synthetic review. ZOOL ANZ 2022. [DOI: 10.1016/j.jcz.2022.05.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Wang L, Dong ZM, Chen GW, Sluys R, Liu DZ. Integrative descriptions of two new species of Dugesia from Hainan Island, China (Platyhelminthes, Tricladida, Dugesiidae). Zookeys 2021; 1028:1-28. [PMID: 33883965 PMCID: PMC8041735 DOI: 10.3897/zookeys.1028.60838] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 02/24/2021] [Indexed: 11/30/2022] Open
Abstract
Two new species of the genus Dugesia (Platyhelminthes, Tricladida, Dugesiidae) from Hainan Island of China are described on the basis of morphological, karyological and molecular data. Dugesiasemiglobosa Chen & Dong, sp. nov. is mainly characterized by a hemispherical, asymmetrical penis papilla with ventrally displaced ejaculatory duct opening terminally at tip of penis papilla; vasa deferentia separately opening into mid-dorsal portion of intrabulbar seminal vesicle; two diaphragms in the ejaculatory duct; copulatory bursa formed by expansion of bursal canal, lined with complex stratified epithelium, which projects through opening in bursa towards intestine, without having open communication with the gut; mixoploid chromosome complement diploid (2n = 16) and triploid (3n = 24), with metacentric chromosomes. Dugesiamajuscula Chen & Dong, sp. nov. is mainly characterized by oviducts opening asymmetrically into female reproductive system; hyperplasic ovaries; expanded posterior section of bursal canal; vasa deferentia separately opening into mid-dorsal portion of seminal vesicle; asymmetrical penis papilla due to ventral course of ejaculatory duct, which has subterminal and dorsal opening at tip papilla; mixoploid chromosome complement diploid (2n = 16) and triploid (3n = 24); chromosomes metacentric. Apart from their anatomy, separate species status of the two new species is supported also by their genetic distances and by their positions in the phylogenetic tree. The sexualization process may have been induced by the lower temperatures, in comparison with their natural habitat, under which the worms were cultured in the laboratory.
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Affiliation(s)
- Lei Wang
- College of Life Science, Henan Normal University, Xinxiang, 453007 Henan, China Henan Normal University Xinxiang China.,Medical College, Xinxiang University, Xinxiang 453003, China Naturalis Biodiversity Center Leiden Netherlands
| | - Zi-Mei Dong
- College of Life Science, Henan Normal University, Xinxiang, 453007 Henan, China Henan Normal University Xinxiang China
| | - Guang-Wen Chen
- College of Life Science, Henan Normal University, Xinxiang, 453007 Henan, China Henan Normal University Xinxiang China
| | - Ronald Sluys
- Naturalis Biodiversity Center, Leiden, the Netherlands Xinxiang University Xinxiang China
| | - De-Zeng Liu
- College of Life Science, Henan Normal University, Xinxiang, 453007 Henan, China Henan Normal University Xinxiang China
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Verberk WC, Atkinson D, Hoefnagel KN, Hirst AG, Horne CR, Siepel H. Shrinking body sizes in response to warming: explanations for the temperature-size rule with special emphasis on the role of oxygen. Biol Rev Camb Philos Soc 2021; 96:247-268. [PMID: 32959989 PMCID: PMC7821163 DOI: 10.1111/brv.12653] [Citation(s) in RCA: 102] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 08/28/2020] [Accepted: 08/28/2020] [Indexed: 01/04/2023]
Abstract
Body size is central to ecology at levels ranging from organismal fecundity to the functioning of communities and ecosystems. Understanding temperature-induced variations in body size is therefore of fundamental and applied interest, yet thermal responses of body size remain poorly understood. Temperature-size (T-S) responses tend to be negative (e.g. smaller body size at maturity when reared under warmer conditions), which has been termed the temperature-size rule (TSR). Explanations emphasize either physiological mechanisms (e.g. limitation of oxygen or other resources and temperature-dependent resource allocation) or the adaptive value of either a large body size (e.g. to increase fecundity) or a short development time (e.g. in response to increased mortality in warm conditions). Oxygen limitation could act as a proximate factor, but we suggest it more likely constitutes a selective pressure to reduce body size in the warm: risks of oxygen limitation will be reduced as a consequence of evolution eliminating genotypes more prone to oxygen limitation. Thus, T-S responses can be explained by the 'Ghost of Oxygen-limitation Past', whereby the resulting (evolved) T-S responses safeguard sufficient oxygen provisioning under warmer conditions, reflecting the balance between oxygen supply and demands experienced by ancestors. T-S responses vary considerably across species, but some of this variation is predictable. Body-size reductions with warming are stronger in aquatic taxa than in terrestrial taxa. We discuss whether larger aquatic taxa may especially face greater risks of oxygen limitation as they grow, which may be manifested at the cellular level, the level of the gills and the whole-organism level. In contrast to aquatic species, terrestrial ectotherms may be less prone to oxygen limitation and prioritize early maturity over large size, likely because overwintering is more challenging, with concomitant stronger end-of season time constraints. Mechanisms related to time constraints and oxygen limitation are not mutually exclusive explanations for the TSR. Rather, these and other mechanisms may operate in tandem. But their relative importance may vary depending on the ecology and physiology of the species in question, explaining not only the general tendency of negative T-S responses but also variation in T-S responses among animals differing in mode of respiration (e.g. water breathers versus air breathers), genome size, voltinism and thermally associated behaviour (e.g. heliotherms).
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Affiliation(s)
- Wilco C.E.P. Verberk
- Department of Animal Ecology and Physiology, Institute for Water and Wetland ResearchRadboud UniversityHeyendaalseweg 1356525 AJNijmegenThe Netherlands
| | - David Atkinson
- Department of Evolution, Ecology and BehaviourUniversity of LiverpoolLiverpoolL69 7ZBU.K.
| | - K. Natan Hoefnagel
- Department of Animal Ecology and Physiology, Institute for Water and Wetland ResearchRadboud UniversityHeyendaalseweg 1356525 AJNijmegenThe Netherlands
- Faculty of Science and Engineering, Ocean Ecosystems — Energy and Sustainability Research Institute GroningenUniversity of GroningenNijenborgh 79747 AGGroningenThe Netherlands
| | - Andrew G. Hirst
- School of Environmental SciencesUniversity of LiverpoolLiverpoolL69 3GPU.K.
- Centre for Ocean Life, DTU AquaTechnical University of DenmarkLyngbyDenmark
| | - Curtis R. Horne
- School of Environmental SciencesUniversity of LiverpoolLiverpoolL69 3GPU.K.
| | - Henk Siepel
- Department of Animal Ecology and Physiology, Institute for Water and Wetland ResearchRadboud UniversityHeyendaalseweg 1356525 AJNijmegenThe Netherlands
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Monnens M, Thijs S, Briscoe AG, Clark M, Frost EJ, Littlewood DTJ, Sewell M, Smeets K, Artois T, Vanhove MPM. The first mitochondrial genomes of endosymbiotic rhabdocoels illustrate evolutionary relaxation of atp8 and genome plasticity in flatworms. Int J Biol Macromol 2020; 162:454-469. [PMID: 32512097 DOI: 10.1016/j.ijbiomac.2020.06.025] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 06/02/2020] [Accepted: 06/03/2020] [Indexed: 02/02/2023]
Abstract
The first three mitochondrial (mt) genomes of endosymbiotic turbellarian flatworms are characterised for the rhabdocoels Graffilla buccinicola, Syndesmis echinorum and S. kurakaikina. Interspecific comparison of the three newly obtained sequences and the only previously characterised rhabdocoel, the free-living species Bothromesostoma personatum, reveals high mt genomic variability, including numerous rearrangements. The first intrageneric comparison within rhabdocoels shows that gene order is not fully conserved even between congeneric species. Atp8, until recently assumed absent in flatworms, was putatively annotated in two sequences. Selection pressure was tested in a phylogenetic framework and is shown to be significantly relaxed in this and another protein-coding gene: cox1. If present, atp8 appears highly derived in platyhelminths and its functionality needs to be addressed in future research. Our findings for the first time allude to a large degree of undiscovered (mt) genomic plasticity in rhabdocoels. It merits further attention whether this variation is correlated with a symbiotic lifestyle. Our results illustrate that this phenomenon is widespread in flatworms as a whole and not exclusive to the better-studied neodermatans.
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Affiliation(s)
- Marlies Monnens
- Hasselt University, Centre for Environmental Sciences, Research Group Zoology: Biodiversity and Toxicology, Agoralaan Gebouw D, B-3590 Diepenbeek, Belgium.
| | - Sofie Thijs
- Hasselt University, Centre for Environmental Sciences, Research Group Environmental Biology, Agoralaan Gebouw D, B-3590 Diepenbeek, Belgium.
| | - Andrew G Briscoe
- Department of Life Sciences, Natural History Museum, Cromwell Road, London SW7 5BD, United Kingdom.
| | - Miriam Clark
- School of Biological Sciences, University of Auckland, New Zealand.
| | - Emily Joy Frost
- School of Biological Sciences, University of Auckland, New Zealand.
| | - D Tim J Littlewood
- Department of Life Sciences, Natural History Museum, Cromwell Road, London SW7 5BD, United Kingdom.
| | - Mary Sewell
- School of Biological Sciences, University of Auckland, New Zealand.
| | - Karen Smeets
- Hasselt University, Centre for Environmental Sciences, Research Group Zoology: Biodiversity and Toxicology, Agoralaan Gebouw D, B-3590 Diepenbeek, Belgium.
| | - Tom Artois
- Hasselt University, Centre for Environmental Sciences, Research Group Zoology: Biodiversity and Toxicology, Agoralaan Gebouw D, B-3590 Diepenbeek, Belgium.
| | - Maarten P M Vanhove
- Hasselt University, Centre for Environmental Sciences, Research Group Zoology: Biodiversity and Toxicology, Agoralaan Gebouw D, B-3590 Diepenbeek, Belgium; Laboratory of Biodiversity and Evolutionary Genomics, University of Leuven, Charles Deberiotstraat 32, B-3000 Leuven, Belgium; Zoology Unit, Finnish Museum of Natural History, University of Helsinki, P.O. Box 17, Helsinki FI-00014, Finland; Department of Botany and Zoology, Faculty of Science, Masaryk University, Kotlářská 2, 611 37 Brno, Czech Republic.
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van de Pol ILE, Flik G, Verberk WCEP. Triploidy in zebrafish larvae: Effects on gene expression, cell size and cell number, growth, development and swimming performance. PLoS One 2020; 15:e0229468. [PMID: 32119699 PMCID: PMC7051096 DOI: 10.1371/journal.pone.0229468] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 02/06/2020] [Indexed: 12/14/2022] Open
Abstract
There is renewed interest in the regulation and consequences of cell size adaptations in studies on understanding the ecophysiology of ectotherms. Here we test if induction of triploidy, which increases cell size in zebrafish (Danio rerio), makes for a good model system to study consequences of cell size. Ideally, diploid and triploid zebrafish should differ in cell size, but should otherwise be comparable in order to be suitable as a model. We induced triploidy by cold shock and compared diploid and triploid zebrafish larvae under standard rearing conditions for differences in genome size, cell size and cell number, development, growth and swimming performance and expression of housekeeping genes and hsp70.1. Triploid zebrafish have larger but fewer cells, and the increase in cell size matched the increase in genome size (+ 50%). Under standard conditions, patterns in gene expression, ontogenetic development and larval growth were near identical between triploids and diploids. However, under demanding conditions (i.e. the maximum swimming velocity during an escape response), triploid larvae performed poorer than their diploid counterparts, especially after repeated stimuli to induce swimming. This result is consistent with the idea that larger cells have less capacity to generate energy, which becomes manifest during repeated physical exertion resulting in increased fatigue. Triploidy induction in zebrafish appears a valid method to increase specifically cell size and this provides a model system to test for consequences of cell size adaptation for the energy budget and swimming performance of this ectothermic vertebrate.
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Affiliation(s)
- Iris L. E. van de Pol
- Department of Animal Ecology and Physiology, Institute for Water and Wetland Research, Radboud University, Nijmegen, The Netherlands
- * E-mail:
| | - Gert Flik
- Department of Animal Ecology and Physiology, Institute for Water and Wetland Research, Radboud University, Nijmegen, The Netherlands
| | - Wilco C. E. P. Verberk
- Department of Animal Ecology and Physiology, Institute for Water and Wetland Research, Radboud University, Nijmegen, The Netherlands
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Abstract
Planarians are on the rise as a model system for regeneration and stem cell dynamics. Almost in parallel the interest in planarian field biology has declined. Besides representing an independent research discipline in its own right, understanding of the natural habitat is also directly relevant to optimizing culture conditions in the laboratory. Moreover, the current laboratory models are but few of hundreds of planarian species worldwide. Their adaptation to a wide range of ecological niches has resulted in a fascinating diversity of regenerative abilities, body size, reproduction strategies, and life expectancy, to name just a few. With the currently ongoing establishment of large planarian species collections, such phenotypic diversity becomes accessible to comparative mechanistic analysis in the laboratory. Overall, we hope that this chapter inspires an integral view of the planarian model system that not only includes the molecular and cellular processes under investigation but also the evolutionary forces that shaped them in the first place.
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Affiliation(s)
- Miquel Vila-Farré
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Jochen C Rink
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany.
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