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Haag ES, Fitch DHA, Delattre M. From "the Worm" to "the Worms" and Back Again: The Evolutionary Developmental Biology of Nematodes. Genetics 2018; 210:397-433. [PMID: 30287515 PMCID: PMC6216592 DOI: 10.1534/genetics.118.300243] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 08/03/2018] [Indexed: 12/13/2022] Open
Abstract
Since the earliest days of research on nematodes, scientists have noted the developmental and morphological variation that exists within and between species. As various cellular and developmental processes were revealed through intense focus on Caenorhabditis elegans, these comparative studies have expanded. Within the genus Caenorhabditis, they include characterization of intraspecific polymorphisms and comparisons of distinct species, all generally amenable to the same laboratory culture methods and supported by robust genomic and experimental tools. The C. elegans paradigm has also motivated studies with more distantly related nematodes and animals. Combined with improved phylogenies, this work has led to important insights about the evolution of nematode development. First, while many aspects of C. elegans development are representative of Caenorhabditis, and of terrestrial nematodes more generally, others vary in ways both obvious and cryptic. Second, the system has revealed several clear examples of developmental flexibility in achieving a particular trait. This includes developmental system drift, in which the developmental control of homologous traits has diverged in different lineages, and cases of convergent evolution. Overall, the wealth of information and experimental techniques developed in C. elegans is being leveraged to make nematodes a powerful system for evolutionary cellular and developmental biology.
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Affiliation(s)
- Eric S Haag
- Department of Biology, University of Maryland, College Park, Maryland 20742
| | | | - Marie Delattre
- Laboratoire de Biologie Moléculaire de la Cellule, CNRS, INSERM, Ecole Normale Supérieure de Lyon, 69007, France
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2
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Sander van Doorn G. Patterns and mechanisms of evolutionary transitions between genetic sex-determining systems. Cold Spring Harb Perspect Biol 2014; 6:cshperspect.a017681. [PMID: 24993578 DOI: 10.1101/cshperspect.a017681] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The diversity and patchy phylogenetic distribution of genetic sex-determining mechanisms observed in some taxa is thought to have arisen by the addition, modification, or replacement of regulators at the upstream end of the sex-determining pathway. Here, I review the various evolutionary forces acting on upstream regulators of sexual development that can cause transitions between sex-determining systems. These include sex-ratio selection and pleiotropic benefits, as well as indirect selection mechanisms involving sex-linked sexually antagonistic loci or recessive deleterious mutations. Most of the current theory concentrates on the population-genetic aspects of sex-determination transitions, using models that do not reflect the developmental mechanisms involved in sex determination. However, the increasing availability of molecular data creates opportunities for the development of mechanistic models that can clarify how selection and developmental architecture interact to direct the evolution of sex-determination genes.
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Affiliation(s)
- G Sander van Doorn
- Centre for Ecological and Evolutionary Studies, University of Groningen, 9700 CC Groningen, The Netherlands
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van Doorn GS. Evolutionary transitions between sex-determining mechanisms: a review of theory. Sex Dev 2013; 8:7-19. [PMID: 24335102 DOI: 10.1159/000357023] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The extraordinary diversity of sex-determining mechanisms found in nature is thought to have arisen by the addition, modification or replacement of regulators at the upstream end of the sex-determining pathway. The spread of a novel regulator of sex determination can manifest itself by an evolutionary transition between environmental and genetic sex determination, for example, or between male and female heterogamety. Both kinds of transition have occurred frequently in the course of evolution. In this paper, various evolutionary forces acting on sex-determining mutations that can bias transitions in one direction or the other are reviewed. Furthermore, the adaptive significance of the main modes of sex determination are discussed, and the common principle underlying ultimate explanations for environmental sex determination, genetic sex determination and maternal control over sex determination in the offspring are highlighted. Most of the current theory concentrates on the population-genetic aspects of sex determination transitions, using models that do not reflect the developmental mechanisms involved in sex determination. However, the increasing availability of molecular data creates opportunities for the future development of mechanistic models that will further clarify how selection and developmental architecture interact to direct the evolution of sex determination genes.
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Affiliation(s)
- G S van Doorn
- Theoretical Biology Group, Centre for Ecological and Evolutionary Studies, University of Groningen, Groningen, The Netherlands
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4
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Using Caenorhabditis to Explore the Evolution of the Germ Line. GERM CELL DEVELOPMENT IN C. ELEGANS 2013; 757:405-25. [DOI: 10.1007/978-1-4614-4015-4_14] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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Chandler CH, Chadderdon GE, Phillips PC, Dworkin I, Janzen FJ. Experimental evolution of the Caenorhabditis elegans sex determination pathway. Evolution 2011; 66:82-93. [PMID: 22220866 DOI: 10.1111/j.1558-5646.2011.01420.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Sex determination is a critical developmental decision with major ecological and evolutionary consequences, yet a large variety of sex determination mechanisms exist and we have a poor understanding of how they evolve. Theoretical and empirical work suggest that compensatory adaptations to mutations in genes involved in sex determination may play a role in the evolution of these pathways. Here, we directly address this problem using experimental evolution in Caenorhabditis elegans lines fixed for a pair of mutations in two key sex-determining genes that jointly render sex determination temperature-sensitive and cause intersexual (but still weakly to moderately fertile) phenotypes at intermediate temperatures. After 50 generations, evolved lines clearly recovered toward wild-type phenotypes. However, changes in transcript levels of key sex-determining genes in evolved lines cannot explain their partially (or in some cases, nearly completely) rescued phenotypes, implying that wild-type phenotypes can be restored independently of the transcriptional effects of these mutations. Our findings highlight the microevolutionary flexibility of sex determination pathways and suggest that compensatory adaptation to mutations can elicit novel and unpredictable evolutionary trajectories in these pathways, mirroring the phylogenetic diversity, and macroevolutionary dynamics of sex determination mechanisms.
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Affiliation(s)
- Christopher H Chandler
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, Iowa 50011, USA
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6
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Reproductive mode evolution in nematodes: insights from molecular phylogenies and recently discovered species. Mol Phylogenet Evol 2011; 61:584-92. [PMID: 21787872 DOI: 10.1016/j.ympev.2011.07.007] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2011] [Revised: 07/06/2011] [Accepted: 07/08/2011] [Indexed: 11/21/2022]
Abstract
The Phylum Nematoda has long been known to contain a great diversity of species that vary in reproductive mode, though our understanding of the evolutionary origins, causes and consequences of nematode reproductive mode change have only recently started to mature. Here we bring together and analyze recent progress on reproductive mode evolution throughout the phylum, resulting from the application of molecular phylogenetic approaches and newly discovered nematode species. Reproductive mode variation is reviewed in multiple free-living, animal-parasitic and plant-parasitic nematode groups. Discussion ranges from the model nematode Caenorhabditis elegans and its close relatives, to the plant-parasitic nematodes of the Meloidogyne genus where there is extreme variation in reproductive mode between and even within species, to the vertebrate-parasitic genus Strongyloides and related genera where reproductive mode varies across generations (heterogony). Multiple evolutionary transitions from dioecous (obligately outcrossing) to hermaphroditism and parthenogenesis in the phylum are discussed, along with one case of an evolutionary transition from hermaphroditism to doioecy in the Oscheius genus. We consider the roles of underlying genetic mechanisms in promoting reproductive plasticity in this phylum, as well as the potential evolutionary forces promoting transitions in reproductive mode.
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Baldi C, Cho S, Ellis RE. Mutations in Two Independent Pathways Are Sufficient to Create Hermaphroditic Nematodes. Science 2009; 326:1002-5. [DOI: 10.1126/science.1176013] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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8
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Kuntz SG, Schwarz EM, DeModena JA, De Buysscher T, Trout D, Shizuya H, Sternberg PW, Wold BJ. Multigenome DNA sequence conservation identifies Hox cis-regulatory elements. Genome Res 2008; 18:1955-68. [PMID: 18981268 DOI: 10.1101/gr.085472.108] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
To learn how well ungapped sequence comparisons of multiple species can predict cis-regulatory elements in Caenorhabditis elegans, we made such predictions across the large, complex ceh-13/lin-39 locus and tested them transgenically. We also examined how prediction quality varied with different genomes and parameters in our comparisons. Specifically, we sequenced approximately 0.5% of the C. brenneri and C. sp. 3 PS1010 genomes, and compared five Caenorhabditis genomes (C. elegans, C. briggsae, C. brenneri, C. remanei, and C. sp. 3 PS1010) to find regulatory elements in 22.8 kb of noncoding sequence from the ceh-13/lin-39 Hox subcluster. We developed the MUSSA program to find ungapped DNA sequences with N-way transitive conservation, applied it to the ceh-13/lin-39 locus, and transgenically assayed 21 regions with both high and low degrees of conservation. This identified 10 functional regulatory elements whose activities matched known ceh-13/lin-39 expression, with 100% specificity and a 77% recovery rate. One element was so well conserved that a similar mouse Hox cluster sequence recapitulated the native nematode expression pattern when tested in worms. Our findings suggest that ungapped sequence comparisons can predict regulatory elements genome-wide.
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Affiliation(s)
- Steven G Kuntz
- Division of Biology, California Institute of Technology, Pasadena, California 91125, USA
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Starostina NG, Lim JM, Schvarzstein M, Wells L, Spence AM, Kipreos ET. A CUL-2 ubiquitin ligase containing three FEM proteins degrades TRA-1 to regulate C. elegans sex determination. Dev Cell 2007; 13:127-39. [PMID: 17609115 PMCID: PMC2064902 DOI: 10.1016/j.devcel.2007.05.008] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2006] [Revised: 04/09/2007] [Accepted: 05/02/2007] [Indexed: 10/23/2022]
Abstract
In Caenorhabditis elegans, the Gli-family transcription factor TRA-1 is the terminal effector of the sex-determination pathway. TRA-1 activity inhibits male development and allows female fates. Genetic studies have indicated that TRA-1 is negatively regulated by the fem-1, fem-2, and fem-3 genes. However, the mechanism of this regulation has not been understood. Here, we present data that TRA-1 is regulated by degradation mediated by a CUL-2-based ubiquitin ligase complex that contains FEM-1 as the substrate-recognition subunit, and FEM-2 and FEM-3 as cofactors. CUL-2 physically associates with both FEM-1 and TRA-1 in vivo, and cul-2 mutant males share feminization phenotypes with fem mutants. CUL-2 and the FEM proteins negatively regulate TRA-1 protein levels in C. elegans. When expressed in human cells, the FEM proteins interact with human CUL2 and induce the proteasome-dependent degradation of TRA-1. This work demonstrates that the terminal step in C. elegans sex determination is controlled by ubiquitin-mediated proteolysis.
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Affiliation(s)
| | - Jae-min Lim
- Complex Carbohydrate Research Center and Department of Biochemistry, University of Georgia, Athens, GA 30602, USA
| | - Mara Schvarzstein
- Department of Molecular and Medical Genetics, University of Toronto, Toronto M5S 1A8, Canada
| | - Lance Wells
- Complex Carbohydrate Research Center and Department of Biochemistry, University of Georgia, Athens, GA 30602, USA
| | - Andrew M. Spence
- Department of Molecular and Medical Genetics, University of Toronto, Toronto M5S 1A8, Canada
| | - Edward T. Kipreos
- Department of Cellular Biology, University of Georgia, Athens, GA 30602, USA
- To whom correspondence should be addressed. Department of Cellular Biology, University of Georgia, 724 Biological Sciences Bldg., Athens, GA 30602-2607, , phone: (706) 542-3862, FAX: (706) 542-4271
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Garcia LR, LeBoeuf B, Koo P. Diversity in mating behavior of hermaphroditic and male-female Caenorhabditis nematodes. Genetics 2007; 175:1761-71. [PMID: 17277358 PMCID: PMC1855125 DOI: 10.1534/genetics.106.068304] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In this study, we addressed why Caenorhabditis elegans males are inefficient at fertilizing their hermaphrodites. During copulation, hermaphrodites generally move away from males before they become impregnated. C. elegans hermaphrodites reproduce by internal self-fertilization, so that copulation with males is not required for species propagation. The hermaphroditic mode of reproduction could potentially relax selection for genes that optimize male mating behavior. We examined males from hermaphroditic and gonochoristic (male-female copulation) Caenorhabditis species to determine if they use different sensory and motor mechanisms to control their mating behavior. Instead, we found through laser ablation analysis and behavioral observations that hermaphroditic C. briggsae and gonochoristic C. remanei and Caenorhabditis species 4, PB2801 males produce a factor that immobilizes females during copulation. This factor also stimulates the vulval slit to widen, so that the male copulatory spicules can easily insert. C. elegans and C. briggsae hermaphrodites are not affected by this factor. We suggest that sensory and motor execution of mating behavior have not significantly changed among males of different Caenorhabditis species; however, during the evolution of internal self-fertilization, hermaphrodites have lost the ability to respond to the male soporific-inducing factor.
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Affiliation(s)
- L Rene Garcia
- Department of Biology, Texas A&M University, College Station, Texas 77843-3258, USA.
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Hill RC, de Carvalho CE, Salogiannis J, Schlager B, Pilgrim D, Haag ES. Genetic flexibility in the convergent evolution of hermaphroditism in Caenorhabditis nematodes. Dev Cell 2006; 10:531-8. [PMID: 16580997 DOI: 10.1016/j.devcel.2006.02.002] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2005] [Revised: 01/25/2006] [Accepted: 02/01/2006] [Indexed: 11/28/2022]
Abstract
The self-fertile hermaphrodites of C. elegans and C. briggsae evolved from female ancestors by acquiring limited spermatogenesis. Initiation of C. elegans hermaphrodite spermatogenesis requires germline translational repression of the female-promoting gene tra-2, which allows derepression of the three male-promoting fem genes. Cessation of hermaphrodite spermatogenesis requires fem-3 translational repression. We show that C. briggsae requires neither fem-2 nor fem-3 for hermaphrodite development, and that XO Cb-fem-2/3 animals are transformed into hermaphrodites, not females as in C. elegans. Exhaustive screens for Cb-tra-2 suppressors identified another 75 fem-like mutants, but all are self-fertile hermaphrodites rather than females. Control of hermaphrodite spermatogenesis therefore acts downstream of the fem genes in C. briggsae. The outwardly similar hermaphrodites of C. elegans and C. briggsae thus achieve self-fertility via intervention at different points in the core sex determination pathway. These findings are consistent with convergent evolution of hermaphroditism, which is marked by considerable developmental genetic flexibility.
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Affiliation(s)
- Robin Cook Hill
- Department of Biology, University of Maryland, College Park, 20742, USA
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