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Sun X, Cheng J. Phylogenetic Signal Dissection of Heterogeneous 28S and 16S rRNA Genes in Spinicaudata (Branchiopoda, Diplostraca). Genes (Basel) 2021; 12:1705. [PMID: 34828311 PMCID: PMC8625258 DOI: 10.3390/genes12111705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 10/20/2021] [Accepted: 10/26/2021] [Indexed: 12/05/2022] Open
Abstract
It is still a challenge to reconstruct the deep phylogenetic relationships within spinicaudatans, and there are several different competing hypotheses regarding the interrelationships among Eocyzicidae, Cyzicidae s. s., Leptestheriidae, and Limnadiidae of the Suborder Spinicaudata. In order to explore the source of the inconsistencies, we focus on the sequence variation and the structure model of two rRNA genes based on extensive taxa sampling. The comparative sequence analysis revealed heterogeneity across species and the existence of conserved motifs in all spinicaudatan species. The level of intraspecific heterogeneity differed among species, which suggested that some species might have undergone a relaxed concerted evolution with respect to the 28S rRNA gene. The Bayesian analyses were performed on nuclear (28S rRNA, EF1α) and mitochondrial (16S rRNA, COI) genes. Further, we investigated compositional heterogeneity between lineages and assessed the potential for phylogenetic noise compared to signal in the combined data set. Reducing the non-phylogenetic signals and application of optimal rRNA model recovered a topology congruent with inference from the transcriptome data, whereby Limnadiidae was placed as a sister group to Leptestheriidae + Eocyzicidae with high support (topology I). Tests of alternative hypotheses provided implicit support for four competing topologies, and topology I was the best.
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Affiliation(s)
| | - Jinhui Cheng
- State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology and Center for Excellence in Life and Palaeoenvironment, Chinese Academy of Sciences, No. 39, Beijing Eastroad, Nanjing 210008, China;
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2
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Chromosome-Wide Evolution and Sex Determination in the Three-Sexed Nematode Auanema rhodensis. G3-GENES GENOMES GENETICS 2019; 9:1211-1230. [PMID: 30770412 PMCID: PMC6469403 DOI: 10.1534/g3.119.0011] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Trioecy, a mating system in which males, females and hermaphrodites co-exist, is a useful system to investigate the origin and maintenance of alternative mating strategies. In the trioecious nematode Auanema rhodensis, males have one X chromosome (XO), whereas females and hermaphrodites have two (XX). The female vs. hermaphrodite sex determination mechanisms have remained elusive. In this study, RNA-seq analyses show a 20% difference between the L2 hermaphrodite and female gene expression profiles. RNAi experiments targeting the DM (doublesex/mab-3) domain transcription factor dmd-10/11 suggest that the hermaphrodite sexual fate requires the upregulation of this gene. The genetic linkage map (GLM) shows that there is chromosome-wide heterozygosity for the X chromosome in F2 hermaphrodite-derived lines originated from crosses between two parental inbred strains. These results confirm the lack of recombination of the X chromosome in hermaphrodites, as previously reported. We also describe conserved chromosome elements (Nigon elements), which have been mostly maintained throughout the evolution of Rhabditina nematodes. The seven-chromosome karyotype of A. rhodensis, instead of the typical six found in other rhabditine species, derives from fusion/rearrangements events involving three Nigon elements. The A. rhodensis X chromosome is the smallest and most polymorphic with the least proportion of conserved genes. This may reflect its atypical mode of father-to-son transmission and its lack of recombination in hermaphrodites and males. In conclusion, this study provides a framework for studying the evolution of chromosomes in rhabditine nematodes, as well as possible mechanisms for the sex determination in a three-sexed species.
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Ford RE, Weeks SC. Intersexual conflict in androdioecious clam shrimp: Do androdioecious hermaphrodites evolve to avoid mating with males? Ethology 2018. [DOI: 10.1111/eth.12738] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Rebecah E. Ford
- Program In Integrated Biosciences; Department of Biology; The University of Akron; Akron OH USA
| | - Stephen C. Weeks
- Program In Integrated Biosciences; Department of Biology; The University of Akron; Akron OH USA
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4
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Sabnis NJ, Kulkarni MR, Padhye SM, Pai K. Hatching phenology, life history and population dynamics of the Oriental clam shrimp Eulimnadia indocylindrova Durga Prasad and Simhachalam with notes on phenology patterns in the Spinicaudata. J NAT HIST 2017. [DOI: 10.1080/00222933.2017.1355996] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Nikita J. Sabnis
- Department of Zoology, Savitribai Phule Pune University, Pune, India
| | - Mihir R. Kulkarni
- Department of Zoology, Savitribai Phule Pune University, Pune, India
| | - Sameer M. Padhye
- Wildlife Information Liaison Development Society, Coimbatore, India
| | - Kalpana Pai
- Department of Zoology, Savitribai Phule Pune University, Pune, India
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5
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De la Varga H, Le Tacon F, Lagoguet M, Todesco F, Varga T, Miquel I, Barry-Etienne D, Robin C, Halkett F, Martin F, Murat C. Five years investigation of female and male genotypes in périgord black truffle (Tuber melanosporum
Vittad.) revealed contrasted reproduction strategies. Environ Microbiol 2017; 19:2604-2615. [DOI: 10.1111/1462-2920.13735] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 03/17/2017] [Accepted: 03/17/2017] [Indexed: 11/27/2022]
Affiliation(s)
- Herminia De la Varga
- UMR1136 Interactions Arbres-Microorganismes, Laboratoire d'Excellence ARBRE; INRA, Université de Lorraine; Champenoux F-54280 France
| | - François Le Tacon
- UMR1136 Interactions Arbres-Microorganismes, Laboratoire d'Excellence ARBRE; INRA, Université de Lorraine; Champenoux F-54280 France
| | - Mélanie Lagoguet
- UMR1136 Interactions Arbres-Microorganismes, Laboratoire d'Excellence ARBRE; INRA, Université de Lorraine; Champenoux F-54280 France
| | - Flora Todesco
- UMR1136 Interactions Arbres-Microorganismes, Laboratoire d'Excellence ARBRE; INRA, Université de Lorraine; Champenoux F-54280 France
| | - Torda Varga
- UMR1136 Interactions Arbres-Microorganismes, Laboratoire d'Excellence ARBRE; INRA, Université de Lorraine; Champenoux F-54280 France
| | - Igor Miquel
- UMR1136 Interactions Arbres-Microorganismes, Laboratoire d'Excellence ARBRE; INRA, Université de Lorraine; Champenoux F-54280 France
| | | | - Christophe Robin
- UMR 1121 Laboratoire Agronomie-Environnement, Nancy-Colmar; INRA, Université de Lorraine; Vandoeuvre-les-Nancy 54518 France
| | - Fabien Halkett
- UMR1136 Interactions Arbres-Microorganismes, Laboratoire d'Excellence ARBRE; INRA, Université de Lorraine; Champenoux F-54280 France
| | - Francis Martin
- UMR1136 Interactions Arbres-Microorganismes, Laboratoire d'Excellence ARBRE; INRA, Université de Lorraine; Champenoux F-54280 France
| | - Claude Murat
- UMR1136 Interactions Arbres-Microorganismes, Laboratoire d'Excellence ARBRE; INRA, Université de Lorraine; Champenoux F-54280 France
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6
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Pannell JR, Auld JR, Brandvain Y, Burd M, Busch JW, Cheptou PO, Conner JK, Goldberg EE, Grant AG, Grossenbacher DL, Hovick SM, Igic B, Kalisz S, Petanidou T, Randle AM, de Casas RR, Pauw A, Vamosi JC, Winn AA. The scope of Baker's law. THE NEW PHYTOLOGIST 2015; 208:656-67. [PMID: 26192018 DOI: 10.1111/nph.13539] [Citation(s) in RCA: 107] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Accepted: 05/27/2015] [Indexed: 05/13/2023]
Abstract
Baker's law refers to the tendency for species that establish on islands by long-distance dispersal to show an increased capacity for self-fertilization because of the advantage of self-compatibility when colonizing new habitat. Despite its intuitive appeal and broad empirical support, it has received substantial criticism over the years since it was proclaimed in the 1950s, not least because it seemed to be contradicted by the high frequency of dioecy on islands. Recent theoretical work has again questioned the generality and scope of Baker's law. Here, we attempt to discern where the idea is useful to apply and where it is not. We conclude that several of the perceived problems with Baker's law fall away when a narrower perspective is adopted on how it should be circumscribed. We emphasize that Baker's law should be read in terms of an enrichment of a capacity for uniparental reproduction in colonizing situations, rather than of high selfing rates. We suggest that Baker's law might be tested in four different contexts, which set the breadth of its scope: the colonization of oceanic islands, metapopulation dynamics with recurrent colonization, range expansions with recurrent colonization, and colonization through species invasions.
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Affiliation(s)
- John R Pannell
- Department of Ecology and Evolution, University of Lausanne, 1015, Lausanne, Switzerland
| | - Josh R Auld
- Department of Biology, West Chester University, West Chester, PA, 19383, USA
| | - Yaniv Brandvain
- Department of Plant Biology, University of Minnesota, St Paul, MN, 55108, USA
| | - Martin Burd
- School of Biological Sciences, Monash University, Melbourne, VIC, 3800, Australia
| | - Jeremiah W Busch
- School of Biological Sciences, Washington State University, Pullman, WA, 99164, USA
| | - Pierre-Olivier Cheptou
- CEFE UMR 5175, CNRS, Universite de Montpellier, Université Paul-Valery Montpellier, EPHE, CEFE 34293, Montpellier Cedex 05, France
| | - Jeffrey K Conner
- Kellogg Biological Station and Department of Plant Biology, Michigan State University, Hickory Corners, MI, 49060, USA
| | - Emma E Goldberg
- Department of Ecology, Evolution, and Behavior, University of Minnesota, St Paul, MN, 55108, USA
| | | | | | - Stephen M Hovick
- Department of Evolution, Ecology, and Organismal Biology, The Ohio State University, Columbus, OH, 43210, USA
| | - Boris Igic
- Department of Biological Sciences, University of Illinois at Chicago, 840 W Taylor St, M/C 067, Chicago, IL, 60607, USA
| | - Susan Kalisz
- Department of Biology, University of Pittsburgh, Pittsburgh, PA, 15260, USA
| | - Theodora Petanidou
- Laboratory of Biogeography and Ecology, Department of Geography, University of the Aegean, 81100 Mytilene, Lesvos, Greece
| | - April M Randle
- Department of Environmental Science, University of San Francisco, San Francisco, CA, 94117-1049, USA
| | - Rafael Rubio de Casas
- CEFE UMR 5175, CNRS, Universite de Montpellier, Université Paul-Valery Montpellier, EPHE, CEFE 34293, Montpellier Cedex 05, France
- Departmento Ecología, Facultad de Ciencias, Universidad de Granada, UGR, 18071, Granada, Spain
- Estación Experimental de Zonas Áridas, EEZA-CSIC, Carretera de Sacramento s/n, La Cañada de San Urbano, EEZA 04120, Almeria, Spain
| | - Anton Pauw
- Department of Botany and Zoology, Stellenbosch University, Stellenbosch, 7602, South Africa
| | - Jana C Vamosi
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, T2N1N4, Canada
| | - Alice A Winn
- Department of Biological Science, Florida State University, Tallahassee, FL, 32306, USA
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Transition in sexual system and sex chromosome evolution in the tadpole shrimp Triops cancriformis. Heredity (Edinb) 2015; 115:37-46. [PMID: 25757406 PMCID: PMC4815504 DOI: 10.1038/hdy.2015.10] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Revised: 01/13/2015] [Accepted: 01/14/2015] [Indexed: 12/19/2022] Open
Abstract
Transitions in sexual system and reproductive mode may affect the course of sex chromosome evolution, for instance by altering the strength of sexually antagonistic selection. However, there have been few studies of sex chromosomes in systems where such transitions have been documented. The European tadpole shrimp, Triops cancriformis, has undergone a transition from dioecy to androdioecy (a sexual system where hermaphrodites and males coexist), offering an excellent opportunity to test the impact of this transition on the evolution of sex chromosomes. To identify sex-linked markers, to understand mechanisms of sex determination and to investigate differences between sexual systems, we carried out a genome-wide association study using restriction site-associated DNA sequencing (RAD-seq) of 47 males, females and hermaphrodites from one dioecious and one androdioecious population. We analysed 22.9 Gb of paired-end sequences and identified and scored >3000 high coverage novel genomic RAD markers. Presence–absence of markers, single-nucleotide polymorphism association and read depth identified 52 candidate sex-linked markers. We show that sex is genetically determined in T. cancriformis, with a ZW system conserved across dioecious and androdioecious populations and that hermaphrodites have likely evolved from females. We also show that the structure of the sex chromosomes differs strikingly, with a larger sex-linked region in the dioecious population compared with the androdioecious population.
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Ellis RE, Lin SY. The evolutionary origins and consequences of self-fertility in nematodes. F1000PRIME REPORTS 2014; 6:62. [PMID: 25165561 PMCID: PMC4126538 DOI: 10.12703/p6-62] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Self-fertile hermaphrodites have evolved from male/female ancestors in many nematode species, and this transition occurred on three independent occasions in the genus Caenorhabditis. Genetic analyses in Caenorhabditis show that the origin of hermaphrodites required two types of changes: alterations to the sex-determination pathway that allowed otherwise female animals to make sperm during larval development, and the production of signals from the gonad that caused these sperm to activate and fertilize oocytes. Comparisons of C. elegans and C. briggsae hermaphrodites show that the ancestral sex-determination pathway has been altered in multiple unique ways. Some of these changes must have precipitated the production of sperm in XX animals, and others were modifying mutations that increased the efficiency of hermaphroditic reproduction. Reverse genetic experiments show that XX animals acquired the ability to activate sperm by co-opting one of the two redundant pathways that normally work in males. Finally, the adoption of a hermaphroditic lifestyle had profound effects on ecological and sexual interactions and genomic organization. Thus, nematode mating systems are ideal for elucidating the origin of novel traits, and studying the influence of developmental processes on evolutionary change.
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Weeks SC, Brantner JS, Astrop TI, Ott DW, Rabet N. The Evolution of Hermaphroditism from Dioecy in Crustaceans: Selfing Hermaphroditism Described in a Fourth Spinicaudatan Genus. Evol Biol 2013. [DOI: 10.1007/s11692-013-9265-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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10
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Kanzaki N, Ragsdale EJ, Herrmann M, Susoy V, Sommer RJ. Two androdioecious and one dioecious new species of pristionchus (nematoda: diplogastridae): new reference points for the evolution of reproductive mode. J Nematol 2013; 45:172-194. [PMID: 24115783 PMCID: PMC3792836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Indexed: 06/02/2023] Open
Abstract
Rhabditid nematodes are one of a few animal taxa in which androdioecious reproduction, involving hermaphrodites and males, is found. In the genus Pristionchus, several cases of androdioecy are known, including the model species P. pacificus. A comprehensive understanding of the evolution of reproductive mode depends on dense taxon sampling and careful morphological and phylogenetic reconstruction. In this article, two new androdioecious species, P. boliviae n. sp. and P. mayeri n. sp., and one gonochoristic outgroup, P. atlanticus n. sp., are described on morphological, molecular, and biological evidence. Their phylogenetic relationships are inferred from 26 ribosomal protein genes and a partial SSU rRNA gene. Based on current representation, the new androdioecious species are sister taxa, indicating either speciation from an androdioecious ancestor or rapid convergent evolution in closely related species. Male sexual characters distinguish the new species, and new characters for six closely related Pristionchus species are presented. Male papillae are unusually variable in P. boliviae n. sp. and P. mayeri n. sp., consistent with the predictions of "selfing syndrome." Description and phylogeny of new androdioecious species, supported by fuller outgroup representation, establish new reference points for mechanistic studies in the Pristionchus system by expanding its comparative context.
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Affiliation(s)
- Natsumi Kanzaki
- Forest Pathology Laboratory, Forestry and Forest Products Research Institute, 1 Matsunosato, Tsukuba, Ibaraki 305-8687 Japan
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11
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Baeza JA, Fuentes MS. Exploring phylogenetic informativeness and nuclear copies of mitochondrial DNA (numts) in three commonly used mitochondrial genes: mitochondrial phylogeny of peppermint, cleaner, and semi-terrestrial shrimps (Caridea:Lysmata,Exhippolysmata, andMerguia). Zool J Linn Soc 2013. [DOI: 10.1111/zoj.12044] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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12
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Addis A, Fabiano F, Delogu V, Carcupino M. Reproductive system morphology of Lightiella magdalenina(Crustacea, Cephalocarida): functional and adaptive implications. INVERTEBR REPROD DEV 2013. [DOI: 10.1080/07924259.2012.704408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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13
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Mathers TC, Hammond RL, Jenner RA, Zierold T, Hänfling B, Gómez A. High lability of sexual system over 250 million years of evolution in morphologically conservative tadpole shrimps. BMC Evol Biol 2013; 13:30. [PMID: 23384124 PMCID: PMC3585860 DOI: 10.1186/1471-2148-13-30] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2012] [Accepted: 01/25/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Sexual system is a key factor affecting the genetic diversity, population structure, genome structure and the evolutionary potential of species. The sexual system androdioecy - where males and hermaphrodites coexist in populations - is extremely rare, yet is found in three crustacean groups, barnacles, a genus of clam shrimps Eulimnadia, and in the order Notostraca, the tadpole shrimps. In the ancient crustacean order Notostraca, high morphological conservatism contrasts with a wide diversity of sexual systems, including androdioecy. An understanding of the evolution of sexual systems in this group has been hampered by poor phylogenetic resolution and confounded by the widespread occurrence of cryptic species. Here we use a multigene supermatrix for 30 taxa to produce a comprehensive phylogenetic reconstruction of Notostraca. Based on this phylogenetic reconstruction we use character mapping techniques to investigate the evolution of sexual systems. We also tested the hypothesis that reproductive assurance has driven the evolution of androdioecy in Notostraca. RESULTS Character mapping analysis showed that sexual system is an extremely flexible trait within Notostraca, with repeated shifts between gonochorism and androdioecy, the latter having evolved a minimum of five times. In agreement with the reproductive assurance hypothesis androdioecious notostracans are found at significantly higher latitudes than gonochoric ones indicating that post glacial re-colonisation may have selected for the higher colonisation ability conferred by androdioecy. CONCLUSIONS In contrast to their conserved morphology, sexual system in Notostraca is highly labile and the rare reproductive mode androdioecy has evolved repeatedly within the order. Furthermore, we conclude that this lability of sexual system has been maintained for at least 250 million years and may have contributed to the long term evolutionary persistence of Notostraca. Our results further our understanding of the evolution of androdioecy and indicate that reproductive assurance is a recurrent theme involved in the evolution of this sexual system.
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Affiliation(s)
- Thomas C Mathers
- School of Biological, Biomedical and Environmental Sciences, University of Hull, Hull, HU6 7RX, UK
| | - Robert L Hammond
- Department of Biology, University of Leicester, University Road, Leicester, LE1 7RH, UK
| | - Ronald A Jenner
- Department of Life Sciences, The Natural History Museum, Cromwell Road, London, SW7 5BD, United Kingdom
| | - Thorid Zierold
- School of Biological, Biomedical and Environmental Sciences, University of Hull, Hull, HU6 7RX, UK
- Museum für Naturkunde Chemnitz, Moritzstrasse 20, D-09111, Chemnitz, Germany
| | - Bernd Hänfling
- School of Biological, Biomedical and Environmental Sciences, University of Hull, Hull, HU6 7RX, UK
| | - Africa Gómez
- School of Biological, Biomedical and Environmental Sciences, University of Hull, Hull, HU6 7RX, UK
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Rabet N, Godinho LB, Montero D, Lacau S. Exploration of the egg shell structure of three NeotropicalEulimnadiaspecies: a new insight into genus taxonomy (Crustacea: Branchiopoda: Spinicaudata). STUDIES ON NEOTROPICAL FAUNA AND ENVIRONMENT 2012. [DOI: 10.1080/01650521.2012.711967] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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15
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Weeks SC. The role of androdioecy and gynodioecy in mediating evolutionary transitions between dioecy and hermaphroditism in the animalia. Evolution 2012. [PMID: 23206127 DOI: 10.1111/j.1558-5646.2012.01714.x] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Dioecy (gonochorism) is dominant within the Animalia, although a recent review suggests hermaphroditism is also common. Evolutionary transitions from dioecy to hermaphroditism (or vice versa) have occurred frequently in animals, but few studies suggest the advantage of such transitions. In particular, few studies assess how hermaphroditism evolves from dioecy or whether androdioecy or gynodioecy should be an "intermediate" stage, as noted in plants. Herein, these transitions are assessed by documenting the numbers of androdioecious and gynodioecious animals and inferring their ancestral reproductive mode. Both systems are rare, but androdioecy was an order of magnitude more common than gynodioecy. Transitions from dioecious ancestors were commonly to androdioecy rather than gynodioecy. Hermaphrodites evolving from sexually dimorphic dioecious ancestors appear to be constrained to those with female-biased sex allocation; such hermaphrodites replace females to coexist with males. Hermaphrodites evolving from sexually monomorphic dioecious ancestors were not similarly constrained. Species transitioning from hermaphroditic ancestors were more commonly androdioecious than gynodioecious, contrasting with similar transitions in plants. In animals, such transitions were associated with size specialization between the sexes, whereas in plants these transitions were to avoid inbreeding depression. Further research should frame these reproductive transitions in a theoretical context, similar to botanical studies.
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Affiliation(s)
- Stephen C Weeks
- Department of Biology, Program in Integrated Bioscience, The University of Akron, Akron, Ohio 44325-3908, USA.
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16
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Chasnov JR. The evolution from females to hermaphrodites results in a sexual conflict over mating in androdioecious nematode worms and clam shrimp. J Evol Biol 2010; 23:539-56. [PMID: 20074309 DOI: 10.1111/j.1420-9101.2009.01919.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The nematode worm Caenorhabditis elegans and the clam shrimp Eulimnadia texana are two well-studied androdioecious species consisting mostly of self-fertilizing hermaphrodites and few males. To understand how androdioecy can evolve, a simple two-step mathematical model of the evolutionary pathway from a male-female species to a selfing-hermaphrodite species is constructed. First, the frequency of mutant females capable of facultative self-fertilization increases if the benefits of reproductive assurance exceed the cost. Second, hermaphrodites become obligate self-fertilizers if the fitness of selfed offspring exceeds one-half the fitness of outcrossed offspring. Genetic considerations specific to C. elegans and E. texana show that males may endure as descendants of the ancestral male-female species. These models combined with an extensive literature review suggest a sexual conflict over mating in these androdioecious species: selection favours hermaphrodites that self and males that outcross. The strength of selection on hermaphrodites and males differs, however. Males that fail to outcross suffer a genetic death. Hermaphrodites may never encounter a rare male, and those that do and outcross only bear less fecund offspring. This asymmetric sexual conflict results in an evolutionary stand-off: rare, but persistent males occasionally fertilize common, but reluctant hermaphrodites. A consequence of this stand-off may be an increase in the longevity of the androdioecious mating system.
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Affiliation(s)
- J R Chasnov
- Department of Mathematics, Hong Kong University of Science and Technology, Kowloon, Hong Kong.
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17
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Velonà A, Luchetti A, Scanabissi F, Mantovani B. Genetic variability and reproductive modalities in European populations ofTriops cancriformis(Crustacea, Branchiopoda, Notostraca). ACTA ACUST UNITED AC 2009. [DOI: 10.1080/11250000902785314] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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18
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WEEKS SC, CHAPMAN EG, ROGERS DC, SENYO DM, HOEH WR. Evolutionary transitions among dioecy, androdioecy and hermaphroditism in limnadiid clam shrimp (Branchiopoda: Spinicaudata). J Evol Biol 2009; 22:1781-99. [DOI: 10.1111/j.1420-9101.2009.01813.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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19
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Consequences of inbreeding depression due to sex-linked loci for the maintenance of males and outcrossing in branchiopod crustaceans. Genet Res (Camb) 2008; 90:73-84. [DOI: 10.1017/s0016672307008981] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
SummaryAndrodioecy, where males co-occur with hermaphrodites, is a rare sexual system in plants and animals. It has a scattered phylogenetic distribution, but it is common and has persisted for long periods of evolutionary time in branchiopod crustaceans. An earlier model of the maintenance of males with hermaphrodites in this group, by Ottoet al.(1993), considered the importance of male–hermaphrodite encounter rates, sperm limitation, male versus hermaphrodite viability and inbreeding depression suffered by selfed progeny. Here I advance this model in two ways: (1) by exploring the conditions that would allow the invasion of hermaphrodites into a dioecious population and that of females into an androdioecious population; and (2) by incorporating a term that accounts for the potential effects of genetic load linked to a dominant hermaphrodite-determining allele in androdioecious populations. The new model makes plausible sense of observations made in populations of the speciesEulimnadia texana, one of a number of related species whose common ancestor evolved hermaphroditism (and androdioecy) from dioecy. In particular, it offers an explanation for the long evolutionary persistence of androdioecy in branchiopods and suggests reasons for why dioecy has not re-evolved in the clade. Finally, it provides a rather unusual illustration of the implications of the degeneration of loci linked to a sex-determining locus.
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Eppley SM, Pannell JR. DENSITY-DEPENDENT SELF-FERTILIZATION AND MALE VERSUS HERMAPHRODITE SIRING SUCCESS IN AN ANDRODIOECIOUS PLANT. Evolution 2007; 61:2349-59. [PMID: 17711472 DOI: 10.1111/j.1558-5646.2007.00195.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Models of mating-system evolution emphasize the importance of frequency-dependent interactions among mating partners. It is also known that outcross siring success and the selfing rate in self-compatible hermaphrodites can be density dependent. Here, we use array experiments to show that the mating system (i.e., the outcrossing rate) and the siring success of morphs with divergent sex allocation strategies are both density dependent and frequency dependent in androdioecious populations of the wind-pollinated, annual plant Mercurialis annua. In particular, the outcrossing rate is a decreasing function of the mean interplant distance, regulated by a negative exponential pollen fall-off curve. Our results indicate that pollen dispersed from a male inflorescence are over 60% more likely to sire outcrossed progeny than equivalent pollen dispersed from hermaphrodites, likely due to the fact that males, but not hermaphrodites, disperse their pollen from erect inflorescence stalks. Because of this difference, and because males of M. annua produce much more pollen than hermaphrodites, the presence of males in the experimental arrays reduced both the selfing rate and the outcross siring success of hermaphrodites. We use our results to infer a density threshold below which males are unable to persist with hermaphrodites but above which they can invade hermaphroditic populations. We discuss our findings in the context of a metapopulation model, in which males can only persist in well-established populations but are excluded from small, sparse populations, for example, in the early stages of colonization.
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Affiliation(s)
- Sarah M Eppley
- Department of Plant Sciences, University of Oxford, Oxford, UK.
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Dolgin ES, Charlesworth B, Baird SE, Cutter AD. INBREEDING AND OUTBREEDING DEPRESSION IN CAENORHABDITIS NEMATODES. Evolution 2007; 61:1339-52. [PMID: 17542844 DOI: 10.1111/j.1558-5646.2007.00118.x] [Citation(s) in RCA: 123] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The nematode Caenorhabditis elegans reproduces primarily by self-fertilization of hermaphrodites, yet males are present at low frequencies in natural populations (androdioecy). The ancestral state of C. elegans was probably gonochorism (separate males and females), as in its relative C. remanei. Males may be maintained in C. elegans because outcrossed individuals escape inbreeding depression. The level of inbreeding depression is, however, expected to be low in such a highly selfing species, compared with an outcrosser like C. remanei. To investigate these issues, we measured life-history traits in the progeny of inbred versus outcrossed C. elegans and C. remanei individuals derived from recently isolated natural populations. In addition, we maintained inbred lines of C. remanei through 13 generations of full-sibling mating. Highly inbred C. remanei showed dramatic reductions in brood size and relative fitness compared to outcrossed individuals, with evidence of both direct genetic and maternal-effect inbreeding depression. This decline in fitness accumulated over time, causing extinction of nearly 90% of inbred lines, with no evidence of purging of deleterious mutations from the remaining lines. In contrast, pure strains of C. elegans performed better than crosses between strains, indicating outbreeding depression. The results are discussed in relation to the evolution of androdioecy and the effect of mating system on the level of inbreeding depression.
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Affiliation(s)
- Elie S Dolgin
- Institute of Evolutionary Biology, University of Edinburgh, King's Buildings, Edinburgh, UK.
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WEEKS STEPHENC, REED SADIEK, CESARI MICHELE, SCANABISSI FRANCA. Production of intersexes and the evolution of androdioecy in the clam shrimpEulimnadia texana(Crustacea, Branchiopoda, Spinicaudata). INVERTEBR REPROD DEV 2006. [DOI: 10.1080/07924259.2006.9652200] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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