51
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Karr TL, Walters JR. Panning for sperm gold: Isolation and purification of apyrene and eupyrene sperm from lepidopterans. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2015; 63:152-158. [PMID: 26141489 DOI: 10.1016/j.ibmb.2015.06.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 06/01/2015] [Accepted: 06/10/2015] [Indexed: 06/04/2023]
Abstract
We describe a simple and straightforward procedure for the purification and separation of apyrene and eupyrene forms of lepidopteran sperm. The procedure is generally applicable to both butterfly and moth species with results varying according to the relative amounts of sperm produced and size of sperm storage organs. The technique relies upon inherent differences between eupyene sperm bundles and free apyrene sperm morphology. These differences allow for separation of the sperm morphs by repeated "panning" of sperm bundles into the center of a plastic dish. The purified eupyrene sperm bundles can then be removed and apyrene sperm collected from the supernatant by centrifugation. Efficacy of the purification process was confirmed by light microscopy and gel electrophoresis of the resulting fractions. Both one- and two-dimensional gel electrophoresis identified significant protein differences between the fractions further suggesting that the panning procedure effectively separated eurpyrene from apyrene sperm. The panning procedure should provide a convenient and accessible technique for further studies of sperm biology in lepidopterans.
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Affiliation(s)
- Timothy L Karr
- Department of Ecology and Evolution, 2041 Haworth Hall, 1200 Sunnyside Avenue, Lawrence, KS 66045, USA.
| | - James R Walters
- Department of Ecology and Evolution, 2041 Haworth Hall, 1200 Sunnyside Avenue, Lawrence, KS 66045, USA
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52
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Fritzsche K, Timmermeyer N, Wolter M, Michiels NK. Female, but not male, nematodes evolve under experimental sexual coevolution. Proc Biol Sci 2015; 281:20140942. [PMID: 25339719 DOI: 10.1098/rspb.2014.0942] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Coevolution between the sexes is often considered to be male-driven: the male genome is constantly scanned by selection for traits that increase relative male fertilization success. Whenever these traits are harmful to females, the female genome is scanned for resistance traits. The resulting antagonistic coevolution between the sexes is analogous to Red Queen dynamics, where adaptation and counteradaptation keep each other in check. However, the underlying assumption that male trait evolution precedes female trait counteradaptation has received few empirical tests. Using the gonochoristic nematode Caenorhabditis remanei, we now show that 20 generations of relaxed versus increased sexual selection pressure lead to female, but not to male, trait evolution, questioning the generality of a male-driven process.
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Affiliation(s)
- K Fritzsche
- Department of Animal Evolutionary Ecology, Institute for Evolution and Ecology, University of Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany
| | - N Timmermeyer
- Department of Animal Evolutionary Ecology, Institute for Evolution and Ecology, University of Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany
| | - M Wolter
- Department of Animal Evolutionary Ecology, Institute for Evolution and Ecology, University of Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany
| | - N K Michiels
- Department of Animal Evolutionary Ecology, Institute for Evolution and Ecology, University of Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany
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53
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Kahrl AF, Cox RM. Diet affects ejaculate traits in a lizard with condition-dependent fertilization success. Behav Ecol 2015. [DOI: 10.1093/beheco/arv105] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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54
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Abstract
Recent research has filled many gaps about Caenorhabditis natural history, simultaneously exposing how much remains to be discovered. This awareness now provides means of connecting ecological and evolutionary theory with diverse biological patterns within and among species in terms of adaptation, sexual selection, breeding systems, speciation, and other phenomena. Moreover, the heralded laboratory tractability of C. elegans, and Caenorhabditis species generally, provides a powerful case study for experimental hypothesis testing about evolutionary and ecological processes to levels of detail unparalleled by most study systems. Here, I synthesize pertinent theory with what we know and suspect about Caenorhabditis natural history for salient features of biodiversity, phenotypes, population dynamics, and interactions within and between species. I identify topics of pressing concern to advance Caenorhabditis biology and to study general evolutionary processes, including the key opportunities to tackle problems in dispersal dynamics, competition, and the dimensionality of niche space.
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Affiliation(s)
- Asher D Cutter
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
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55
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Palopoli MF, Peden C, Woo C, Akiha K, Ary M, Cruze L, Anderson JL, Phillips PC. Natural and experimental evolution of sexual conflict within Caenorhabditis nematodes. BMC Evol Biol 2015; 15:93. [PMID: 25994934 PMCID: PMC4455605 DOI: 10.1186/s12862-015-0377-2] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Accepted: 05/08/2015] [Indexed: 12/04/2022] Open
Abstract
Background Although males and females need one another in order to reproduce, they often have different reproductive interests, which can lead to conflict between the sexes. The intensity and frequency of male-male competition for fertilization opportunities is thought to be an important contributor to this conflict. The nematode genus Caenorhabditis provides an opportunity to test this hypothesis because the frequency of males varies widely among species with different mating systems. Results We find evidence that there is strong inter- and intra-sexual conflict within C. remanei, a dioecious species composed of equal frequencies of males and females. In particular, some C. remanei males greatly reduce female lifespan following mating, and their sperm have a strong competitive advantage over the sperm of other males. In contrast, our results suggest that both types of conflict have been greatly reduced within C. elegans, which is an androdioecious species that is composed of self-fertilizing hermaphrodites and rare males. Using experimental evolution in mutant C. elegans populations in which sperm production is blocked in hermaphrodites (effectively converting them to females), we find that the consequences of sexual conflict observed within C. remanei evolve rapidly within C. elegans populations experiencing high levels of male-male competition. Conclusions Together, these complementary data sets support the hypothesis that the intensity of intersexual conflict varies with the intensity of competition among males, and that male-induced collateral damage to mates can evolve very rapidly within populations.
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Affiliation(s)
| | - Colin Peden
- Institute of Ecology and Evolution, University of Oregon, OR 97403, Eugene, USA.
| | - Caitlin Woo
- Department of Biology, Bowdoin College, ME 04011, Brunswick, USA.
| | - Ken Akiha
- Department of Biology, Bowdoin College, ME 04011, Brunswick, USA.
| | - Megan Ary
- Institute of Ecology and Evolution, University of Oregon, OR 97403, Eugene, USA. .,Current address: South Lane School District, OR 97424, Cottage Grove, USA.
| | - Lori Cruze
- Institute of Ecology and Evolution, University of Oregon, OR 97403, Eugene, USA. .,Current address: Department of Obstetrics and Gynecology, Medical University of South Carolina, SC 29412, Charleston, USA.
| | - Jennifer L Anderson
- Institute of Ecology and Evolution, University of Oregon, OR 97403, Eugene, USA. .,Current address: INRA, UR1037 LPGP, Campus de Beaulieu, F-35000, Rennes, France.
| | - Patrick C Phillips
- Institute of Ecology and Evolution, University of Oregon, OR 97403, Eugene, USA.
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56
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Boulton RA, Collins LA, Shuker DM. Beyond sex allocation: the role of mating systems in sexual selection in parasitoid wasps. Biol Rev Camb Philos Soc 2015; 90:599-627. [PMID: 24981603 PMCID: PMC4409842 DOI: 10.1111/brv.12126] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Revised: 05/19/2014] [Accepted: 05/28/2014] [Indexed: 11/30/2022]
Abstract
Despite the diverse array of mating systems and life histories which characterise the parasitic Hymenoptera, sexual selection and sexual conflict in this taxon have been somewhat overlooked. For instance, parasitoid mating systems have typically been studied in terms of how mating structure affects sex allocation. In the past decade, however, some studies have sought to address sexual selection in the parasitoid wasps more explicitly and found that, despite the lack of obvious secondary sexual traits, sexual selection has the potential to shape a range of aspects of parasitoid reproductive behaviour and ecology. Moreover, various characteristics fundamental to the parasitoid way of life may provide innovative new ways to investigate different processes of sexual selection. The overall aim of this review therefore is to re-examine parasitoid biology with sexual selection in mind, for both parasitoid biologists and also researchers interested in sexual selection and the evolution of mating systems more generally. We will consider aspects of particular relevance that have already been well studied including local mating structure, sex allocation and sperm depletion. We go on to review what we already know about sexual selection in the parasitoid wasps and highlight areas which may prove fruitful for further investigation. In particular, sperm depletion and the costs of inbreeding under chromosomal sex determination provide novel opportunities for testing the role of direct and indirect benefits for the evolution of mate choice.
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Affiliation(s)
- Rebecca A Boulton
- Centre for Biological Diversity, School of Biology, University of St AndrewsDyers Brae, Greenside place, Fife KY16 9TH, U.K.
| | - Laura A Collins
- Centre for Biological Diversity, School of Biology, University of St AndrewsDyers Brae, Greenside place, Fife KY16 9TH, U.K.
| | - David M Shuker
- Centre for Biological Diversity, School of Biology, University of St AndrewsDyers Brae, Greenside place, Fife KY16 9TH, U.K.
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57
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Abstract
Male nematode worms may make larger sperm than hermaphrodite worms, but this is not the only reason that sperm from males have a competitive edge.
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Affiliation(s)
- Ronald E Ellis
- Department of Molecular Biology, Rowan University School of Osteopathic Medicine, Stratford, United States
| | - Qing Wei
- Rowan University Graduate School of Biomedical Sciences, Stratford, United States
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58
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Hansen JM, Chavez DR, Stanfield GM. COMP-1 promotes competitive advantage of nematode sperm. eLife 2015; 4:e05423. [PMID: 25789512 PMCID: PMC4400581 DOI: 10.7554/elife.05423] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 03/16/2015] [Indexed: 12/24/2022] Open
Abstract
Competition among sperm to fertilize oocytes is a ubiquitous feature of sexual reproduction as well as a profoundly important aspect of sexual selection. However, little is known about the cellular mechanisms sperm use to gain competitive advantage or how these mechanisms are regulated genetically. In this study, we utilize a forward genetic screen in Caenorhabditis elegans to identify a gene, comp-1, whose function is specifically required in competitive contexts. We show that comp-1 functions in sperm to modulate their migration through and localization within the reproductive tract, thereby promoting their access to oocytes. Contrary to previously described models, comp-1 mutant sperm show no defects in size or velocity, thereby defining a novel pathway for preferential usage. Our results indicate not only that sperm functional traits can influence the outcome of sperm competition, but also that these traits can be modulated in a context-dependent manner depending on the presence of competing sperm.
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Affiliation(s)
- Jody M Hansen
- Department of Human Genetics, University of Utah, Salt Lake City, United States
| | - Daniela R Chavez
- Department of Human Genetics, University of Utah, Salt Lake City, United States
| | - Gillian M Stanfield
- Department of Human Genetics, University of Utah, Salt Lake City, United States
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59
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Dutilleul M, Bonzom JM, Lecomte C, Goussen B, Daian F, Galas S, Réale D. Rapid evolutionary responses of life history traits to different experimentally-induced pollutions in Caenorhabditis elegans. BMC Evol Biol 2014; 14:252. [PMID: 25491302 PMCID: PMC4272515 DOI: 10.1186/s12862-014-0252-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Accepted: 11/20/2014] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Anthropogenic disturbances can lead to intense selection pressures on traits and very rapid evolutionary changes. Evolutionary responses to environmental changes, in turn, reflect changes in the genetic structure of the traits, accompanied by a reduction of evolutionary potential of the populations under selection. Assessing the effects of pollutants on the evolutionary responses and on the genetic structure of populations is thus important to understanding the mechanisms that entail specialization to novel environmental conditions or resistance to novel stressors. RESULTS Using an experimental evolution approach we exposed Caenorhabditis elegans populations to uranium, salt and alternating uranium-salt environments over 22 generations. We analyzed the changes in the average values of life history traits and the consequences at the demographic level in these populations. We also estimated the phenotypic and genetic (co)variance structure of these traits at different generations. Compared to populations in salt, populations in uranium showed a reduction of the stability of their trait structure and a higher capacity to respond by acclimation. However, the evolutionary responses of traits were generally lower for uranium compared to salt treatment; and the evolutionary responses to the alternating uranium-salt environment were between those of constant environments. Consequently, at the end of the experiment, the population rate of increase was higher in uranium than in salt and intermediate in the alternating environment. CONCLUSIONS Our multigenerational experiment confirmed that rapid adaptation to different polluted environments may involve different evolutionary responses resulting in demographic consequences. These changes are partly explained by the effects of the pollutants on the genetic (co)variance structure of traits and the capacity of acclimation to novel conditions. Finally, our results in the alternating environment may confirm the selection of a generalist type in this environment.
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Affiliation(s)
- Morgan Dutilleul
- Département des Sciences Biologiques, Université du Québec À Montréal, Montreal, Canada.
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV/SERIS/LECO, Cadarache, Bât 183, BP 3, 13115, St Paul-lez-Durance, France.
- Université de Montpellier 1, Faculté de pharmacie, Laboratoire de Toxicologie, BP 14491, F-34093, Montpellier Cedex 5, France.
| | - Jean-Marc Bonzom
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV/SERIS/LECO, Cadarache, Bât 183, BP 3, 13115, St Paul-lez-Durance, France.
| | - Catherine Lecomte
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV/SERIS/LECO, Cadarache, Bât 183, BP 3, 13115, St Paul-lez-Durance, France.
| | - Benoit Goussen
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV/SERIS/LECO, Cadarache, Bât 183, BP 3, 13115, St Paul-lez-Durance, France.
- Unit "Models for ecotoxicology and toxicology" (METO) INERIS Parc ALATA, BP2 60550, Verneuil-en-Halatte, France.
| | - Fabrice Daian
- Institut de Biologie du Développement de Marseille-Luminy, UMR7288, CNRS, F-13288, Marseille Cedex 9, France.
| | - Simon Galas
- Université de Montpellier 1, Faculté de pharmacie, Laboratoire de Toxicologie, BP 14491, F-34093, Montpellier Cedex 5, France.
| | - Denis Réale
- Département des Sciences Biologiques, Université du Québec À Montréal, Montreal, Canada.
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60
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Haeussler E, Schmera D, Baur B. Parasitic mites influence intra- and interpopulational variation in sperm length in a simultaneous hermaphrodite land snail (Gastropoda: Helicidae). Biol J Linn Soc Lond 2014. [DOI: 10.1111/bij.12377] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ellen Haeussler
- Section of Conservation Biology; Department of Environmental Sciences; University of Basel; St. Johanns-Vorstadt 10 CH-4056 Basel Switzerland
| | - Denes Schmera
- Section of Conservation Biology; Department of Environmental Sciences; University of Basel; St. Johanns-Vorstadt 10 CH-4056 Basel Switzerland
| | - Bruno Baur
- Section of Conservation Biology; Department of Environmental Sciences; University of Basel; St. Johanns-Vorstadt 10 CH-4056 Basel Switzerland
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61
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Shinya R, Hasegawa K, Chen A, Kanzaki N, Sternberg PW. Evidence of hermaphroditism and sex ratio distortion in the fungal feeding nematode Bursaphelenchus okinawaensis. G3 (BETHESDA, MD.) 2014; 4:1907-17. [PMID: 25122669 PMCID: PMC4199697 DOI: 10.1534/g3.114.012385] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Accepted: 08/01/2014] [Indexed: 11/18/2022]
Abstract
Nematodes have many different reproductive strategies along with their divergent life histories; the ability of hermaphrodite to self- and cross-fertilize is useful for genetic manipulation. Here, we demonstrate the hermaphroditism of the fungal feeding nematode Bursaphelenchus okinawaensis, which was formerly described as a parthenogenetic nematode, and we show its other unique sexual characteristics. To determine that it is hermaphroditic, we performed the following experiments: observation of the pronuclear and chromosome behavior during oogenesis and early embryogenesis; observation of spermatogenesis during the fourth larval stage; investigation of sperm utilization; and investigation of phenotypic segregation after cross-mating using a chemically induced visible mutant. We then investigated the mating preferences and spermatid size difference between males and hermaphrodites. B. okinawaensis males successfully mated only with sperm-depleted old hermaphrodites, and the spermatid sizes of males were almost the same as those of hermaphrodites. Moreover, the sex ratio of cross-fertilized progeny was highly skewed toward hermaphrodites. B. okinawaensis is phylogenetically distant from established model nematodes such as C. elegans and is more closely related to some economically relevant parasitic nematodes. This newly discovered hermaphroditic nematode has great potential for evolutionary and parasitological research.
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Affiliation(s)
- Ryoji Shinya
- Howard Hughes Medical Institute and Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125 Department of the Environmental Biology, College of Bioscience and Biotechnology, Chubu University, Kasugai 487-8501 Japan
| | - Koichi Hasegawa
- Department of the Environmental Biology, College of Bioscience and Biotechnology, Chubu University, Kasugai 487-8501 Japan
| | - Anthony Chen
- Howard Hughes Medical Institute and Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125
| | - Natsumi Kanzaki
- Forestry and Forest Products Research Institute, Tsukuba 305-8687, Japan
| | - Paul W Sternberg
- Howard Hughes Medical Institute and Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125
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62
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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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63
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Abstract
Intense reproductive competition often continues long after animals finish mating. In many species, sperm from one male compete with those from others to find and fertilize oocytes. Since this competition occurs inside the female reproductive tract, she often influences the outcome through physical or chemical factors, leading to cryptic female choice. Finally, traits that help males compete with each other are sometimes harmful to females, and female countermeasures may thwart the interests of males, which can lead to an arms race between the sexes known as sexually antagonistic coevolution. New studies from Caenorhabditis nematodes suggest that males compete with each other by producing sperm that migrate aggressively and that these sperm may be more likely to win access to oocytes. However, one byproduct of this competition appears to be an increased probability that these sperm will go astray, invading the ovary, prematurely activating oocytes, and sometimes crossing basement membranes and leaving the gonad altogether. These harmful effects are sometimes observed in crosses between animals of the same species but are most easily detected in interspecies crosses, leading to dramatically lowered fitness, presumably because the competitiveness of the sperm and the associated female countermeasures are not precisely matched. This mismatch is most obvious in crosses involving individuals from androdioecious species (which have both hermaphrodites and males), as predicted by the lower levels of sperm competition these species experience. These results suggest a striking example of sexually antagonistic coevolution and dramatically expand the value of nematodes as a laboratory system for studying postcopulatory interactions.
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Affiliation(s)
- Ronald E. Ellis
- Department of Molecular Biology, Rowan University SOM, Stratford, New Jersey, United States of America
| | - Lukas Schärer
- Evolutionary Biology, Zoological Institute, University of Basel, Basel, Switzerland
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64
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Ellis RE, Stanfield GM. The regulation of spermatogenesis and sperm function in nematodes. Semin Cell Dev Biol 2014; 29:17-30. [PMID: 24718317 PMCID: PMC4082717 DOI: 10.1016/j.semcdb.2014.04.005] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Accepted: 04/01/2014] [Indexed: 12/12/2022]
Abstract
In the nematode C. elegans, both males and self-fertile hermaphrodites produce sperm. As a result, researchers have been able to use a broad range of genetic and genomic techniques to dissect all aspects of sperm development and function. Their results show that the early stages of spermatogenesis are controlled by transcriptional and translational processes, but later stages are dominated by protein kinases and phosphatases. Once spermatids are produced, they participate in many interactions with other cells - signals from the somatic gonad determine when sperm activate and begin to crawl, signals from the female reproductive tissues guide the sperm, and signals from sperm stimulate oocytes to mature and be ovulated. The sperm also show strong competitive interactions with other sperm and oocytes. Some of the molecules that mediate these processes have conserved functions in animal sperm, others are conserved proteins that have been adapted for new roles in nematode sperm, and some are novel proteins that provide insights into evolutionary change. The advent of new techniques should keep this system on the cutting edge of research in cellular and reproductive biology.
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Affiliation(s)
- Ronald E Ellis
- Department of Molecular Biology, Rowan University SOM, B303 Science Center, 2 Medical Center Drive, Stratford, NJ 08084, United States.
| | - Gillian M Stanfield
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, United States
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65
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Prakash S, Prithiviraj E, Suresh S, Lakshmi NV, Ganesh MK, Anuradha M, Ganesh L, Dinesh P. Morphological diversity of sperm: A mini review. IRANIAN JOURNAL OF REPRODUCTIVE MEDICINE 2014; 12:239-42. [PMID: 24976817 PMCID: PMC4071627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Subscribe] [Scholar Register] [Received: 12/27/2012] [Revised: 07/13/2013] [Accepted: 11/17/2013] [Indexed: 11/21/2022]
Abstract
Sperms are highly specialized cells for delivering DNA from male to the ovum. Incredibly, wide degree of diversity in sperm morphology in their basic structures i.e. head, middle piece and tail is found across species. Differences in terms of overall size of the sperm, shape and number of sperm produced are also incredible. One of the key for this variations or diversity in sperm may be associated with female reproductive tract, sperm competition, testicular size and sperm size and number. Establishing a correlation between sperm morphology and factors influencing them is a phenomenal task. In this mini-review these associations and the anatomical and functional adaptations among different from of sperm cells that have evolved to optimize fertilization success are discussed. Nevertheless, explaining these morphological diversities in sperm cells is a challenging question and it seems that evolutionary biologists have only recently engaged in exploring its links and patterns. From the literatures it seems that there is no causal relationship between sperm size and testicular size, however, the accumulated knowledge do indicates evolution of sperm morphology across species has some associations with female reproductive tract, sperm competition and sperm size and number, however interpreting these results for phylogentic correlations should be approached with caution.
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Affiliation(s)
- Seppan Prakash
- Department of Anatomy, Dr. Arcot Lakshmanasamy Mudaliar Postgraduate Institute of Basic Medical Sciences, University of Madras, Taramani Campus, Chennai, India
| | - Elumalai Prithiviraj
- Department of Anatomy, Dr. Arcot Lakshmanasamy Mudaliar Postgraduate Institute of Basic Medical Sciences, University of Madras, Taramani Campus, Chennai, India
| | - Sekar Suresh
- Department of Anatomy, Dr. Arcot Lakshmanasamy Mudaliar Postgraduate Institute of Basic Medical Sciences, University of Madras, Taramani Campus, Chennai, India
| | - Nagella Venkata Lakshmi
- Department of Anatomy, Dr. Arcot Lakshmanasamy Mudaliar Postgraduate Institute of Basic Medical Sciences, University of Madras, Taramani Campus, Chennai, India
| | - Mohanraj Karthik Ganesh
- Department of Anatomy, Dr. Arcot Lakshmanasamy Mudaliar Postgraduate Institute of Basic Medical Sciences, University of Madras, Taramani Campus, Chennai, India
| | - Murugesan Anuradha
- Department of Anatomy, Dr. Arcot Lakshmanasamy Mudaliar Postgraduate Institute of Basic Medical Sciences, University of Madras, Taramani Campus, Chennai, India
| | - Lakshmanan Ganesh
- Department of Anatomy, Dr. Arcot Lakshmanasamy Mudaliar Postgraduate Institute of Basic Medical Sciences, University of Madras, Taramani Campus, Chennai, India
| | - Premavathy Dinesh
- Department of Anatomy, Dr. Arcot Lakshmanasamy Mudaliar Postgraduate Institute of Basic Medical Sciences, University of Madras, Taramani Campus, Chennai, India
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66
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Ramm SA, Schärer L. The evolutionary ecology of testicular function: size isn't everything. Biol Rev Camb Philos Soc 2014; 89:874-88. [DOI: 10.1111/brv.12084] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Revised: 12/23/2013] [Accepted: 01/12/2014] [Indexed: 12/22/2022]
Affiliation(s)
- Steven A. Ramm
- Evolutionary Biology; Bielefeld University; Morgenbreede 45 33615 Bielefeld Germany
| | - Lukas Schärer
- Evolutionary Biology; Zoological Institute, University of Basel; Vesalgasse 1 4051 Basel Switzerland
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67
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Abstract
Interactions between the germ line and the soma help optimize reproductive success. We discovered a phenomenon linking reproductive status to longevity: In both hermaphroditic and gonochoristic Caenorhabditis, mating leads to female shrinking and death, compressing postreproductive life span. Male sperm induces germline- and DAF-9/DAF-12-dependent shrinking, osmotic stress susceptibility, and subsequent life-span decrease, whereas seminal fluid induces DAF-16-dependent life-span decrease and fat loss. Our study provides insight into the communication between males and the female germ line and soma to regulate reproduction and longevity, revealing a high-reproduction, low-life-span state induced by mating. Postmating somatic collapse may be an example of the sexually antagonistic influence that males in many species exert on female behavior to maximize their own reproductive success.
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Affiliation(s)
- Cheng Shi
- Lewis-Sigler Institute for Integrative Genomics and Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Coleen T. Murphy
- Lewis-Sigler Institute for Integrative Genomics and Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
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No experimental evidence for sneaking in a west african cichlid fish with extremely long sperm. INTERNATIONAL JOURNAL OF EVOLUTIONARY BIOLOGY 2014; 2013:714304. [PMID: 24386589 PMCID: PMC3872403 DOI: 10.1155/2013/714304] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Accepted: 10/10/2013] [Indexed: 11/17/2022]
Abstract
Alternative reproductive tactics are widespread in fishes, increasing the potential for sperm competition. Sperm competition has enormous impact on both variation in sperm numbers and sperm size. In cichlids, the sperm competition risk is very divergent and longer sperm are usually interpreted as adaptation to sperm competition. Here we examined whether sneaking tactics exist in Pelvicachromis taeniatus, a socially monogamous cichlid with biparental brood care from West Africa. The small testis indicates low gonadal investment which is typical for genetically monogamous species. In contrast, sperm length with up to 85 μm is extraordinarily long. We examined the reproductive behaviour of ten groups with a male-biased sex ratio under semi-natural conditions via continuous video recording. We recorded spawning site preferences and correlates of reproductive success and conducted paternity tests using microsatellites. Safe breeding sites that could be successfully defended were preferred. All offspring could be assigned to their parents and no multiple paternities were detected. Body size of spawning pairs predicted their spawning probability and offspring hatching rate suggesting benefits from mating with large individuals. Our study suggests low risk of sperm competition under the given conditions in P. taeniatus and thus first evidence for genetic monogamy in a substrate breeding cichlid.
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69
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Sharma MD, Minder AM, Hosken DJ. No association between sperm competition and sperm length variation across dung flies (Scathophagidae). J Evol Biol 2013; 26:2341-9. [PMID: 24016061 DOI: 10.1111/jeb.12232] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Revised: 07/03/2013] [Accepted: 07/04/2013] [Indexed: 11/29/2022]
Abstract
Sperm length is extremely variable across species, but a general explanation for this variation is lacking. However, when the risk of sperm competition is high, sperm length is predicted to be less variable within species, and there is some evidence for this in birds and social insects. Here, we examined intraspecific variation in sperm length, both within and between males, and its potential associations with sperm competition risk and variation in female reproductive tract morphology across dung flies. We used two measures of variation in sperm size, and testis size was employed as our index of sperm competition risk. We found no evidence of associations between sperm length variation and sperm competition or female reproductive tract variation. These results suggest that variation in sperm competition risk may not always be associated with variation in sperm morphology, and the cause(s) of sperm length variation in dung flies remains unclear.
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Affiliation(s)
- M D Sharma
- Centre for Conservation & Ecology, College of Life and Environmental Sciences, University of Exeter, Tremough, Penryn, UK
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70
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Soper DM, Neiman M, Savytskyy OP, Zolan ME, Lively CM. Spermatozoa Production by Triploid Males in the New Zealand Freshwater Snail Potamopyrgus antipodarum.. Biol J Linn Soc Lond 2013; 110:227-234. [PMID: 24307744 PMCID: PMC3844136 DOI: 10.1111/bij.12085] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Revised: 03/03/2013] [Accepted: 03/05/2013] [Indexed: 11/28/2022]
Abstract
Asexual lineages derived from dioecious taxa are typically assumed to be all female. Even so, asexual females from a variety of animal taxa occasionally produce males. The existence of these males sets the stage for potential gene flow across asexual lineages as well as between sexual and asexual lineages. A recent study showed that asexual triploid female Potamopyrgus antipodarum, a New Zealand freshwater snail often used as a model to study sexual reproduction, occasionally produce triploid male offspring. Here, we show that these triploid male P. antipodarum 1) have testes that produce morphologically normal sperm, 2) make larger sperm cells that contain more nuclear DNA than the sperm produced by diploid sexual males, and 3) produce sperm that range in DNA content from haploid to diploid, and are often aneuploid. Analysis of meiotic chromosomes of triploid males showed that aberrant pairing during prophase I likely accounts for the high variation in DNA content among sperm. These results indicate that triploid male P. antipodarum produce sperm, but the extent to which these sperm are able to fertilize female ova remains unclear. Our results also suggest that the general assumption of sterility in triploid males should be more closely examined in other species in which such males are occasionally produced.
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Affiliation(s)
- Deanna M. Soper
- Department of Biology, Indiana University, Bloomington, IN, USA
| | - Maurine Neiman
- Department of Biology, University of Iowa, Iowa City, IA, USA
| | | | - Miriam E. Zolan
- Department of Biology, Indiana University, Bloomington, IN, USA
| | - Curt M. Lively
- Department of Biology, Indiana University, Bloomington, IN, USA
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71
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Manier MK, Belote JM, Berben KS, Lüpold S, Ala-Honkola O, Collins WF, Pitnick S. Rapid diversification of sperm precedence traits and processes among three sibling Drosophila species. Evolution 2013; 67:2348-62. [PMID: 23888856 DOI: 10.1111/evo.12117] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Accepted: 03/12/2013] [Indexed: 01/13/2023]
Abstract
Postcopulatory sexual selection is credited with driving rapid evolutionary diversification of reproductive traits and the formation of reproductive isolating barriers between species. This judgment, however, has largely been inferred rather than demonstrated due to general lack of knowledge about processes and traits underlying variation in competitive fertilization success. Here, we resolved processes determining sperm fate in twice-mated females, using transgenic Drosophila simulans and Drosophila mauritiana populations with fluorescently labeled sperm heads. Comparisons among these two species and Drosophila melanogaster revealed a shared motif in the mechanisms of sperm precedence, with postcopulatory sexual selection potentially occurring during any of the three discrete stages: (1) insemination; (2) sperm storage; and (3) sperm use for fertilization, and involving four distinct phenomena: (1) sperm transfer; (2) sperm displacement; (3) sperm ejection; and (4) sperm selection for fertilizations. Yet, underlying the qualitative similarities were significant quantitative differences in nearly every relevant character and process. We evaluate these species differences in light of concurrent investigations of within-population variation in competitive fertilization success and postmating/prezygotic reproductive isolation in hybrid matings between species to forge an understanding of the relationship between microevolutionary processes and macroevolutionary patterns as pertains to postcopulatory sexual selection in this group.
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Affiliation(s)
- Mollie K Manier
- Department of Biology, Syracuse University, Syracuse, New York 13244, USA
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72
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Niksirat H, Kouba A, Pšenička M, Kuklina I, Kozák P. Ultrastructure of spermatozoa from three genera of crayfish Orconectes, Procambarus and Astacus (Decapoda: Astacoidea): New findings and comparisons. ZOOL ANZ 2013. [DOI: 10.1016/j.jcz.2012.06.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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73
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74
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75
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Singaravelu G, Singson A. Calcium signaling surrounding fertilization in the nematode Caenorhabditis elegans. Cell Calcium 2012; 53:2-9. [PMID: 23218668 DOI: 10.1016/j.ceca.2012.11.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Revised: 11/02/2012] [Accepted: 11/03/2012] [Indexed: 01/17/2023]
Abstract
Calcium plays a prominent role during fertilization in many animals. This review focuses on roles of Ca(2+) during the events around fertilization in the model organism, Caenorhabditis elegans. Specifically, the role of Ca(2+) in sperm, oocytes and the surrounding somatic tissues during fertilization will be discussed, with the focus on sperm activation, meiotic maturation of oocytes, ovulation, sperm-egg interaction and fertilization.
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76
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Abstract
Females frequently mate with several males, whose sperm then compete to fertilize available ova. Sperm competition represents a potent selective force that is expected to shape male expenditure on the ejaculate. Here, we review empirical data that illustrate the evolutionary consequences of sperm competition. Sperm competition favors the evolution of increased testes size and sperm production. In some species, males appear capable of adjusting the number of sperm ejaculated, depending on the perceived levels of sperm competition. Selection is also expected to act on sperm form and function, although the evidence for this remains equivocal. Comparative studies suggest that sperm length and swimming speed may increase in response to selection from sperm competition. However, the mechanisms driving this pattern remain unclear. Evidence that sperm length influences sperm swimming speed is mixed and fertilization trials performed across a broad range of species demonstrate inconsistent relationships between sperm form and function. This ambiguity may in part reflect the important role that seminal fluid proteins (sfps) play in affecting sperm function. There is good evidence that sfps are subject to selection from sperm competition, and recent work is pointing to an ability of males to adjust their seminal fluid chemistry in response to sperm competition from rival males. We argue that future research must consider sperm and seminal fluid components of the ejaculate as a functional unity. Research at the genomic level will identify the genes that ultimately control male fertility.
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Affiliation(s)
- Leigh W Simmons
- Centre for Evolutionary Biology, , School of Animal Biology (M092), The University of Western Australia, Crawley, Western Australia 6009, Australia.
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77
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Miersch C, Döring F. Sex differences in carbohydrate metabolism are linked to gene expression in Caenorhabditis elegans. PLoS One 2012; 7:e44748. [PMID: 22984551 PMCID: PMC3439400 DOI: 10.1371/journal.pone.0044748] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2012] [Accepted: 08/06/2012] [Indexed: 11/18/2022] Open
Abstract
The male and the hermaphrodite forms of the nematode Caenorhabditis elegans (C. elegans) differ markedly in anatomy, nervous system and behavior at adulthood. Using the male mutants fog-2, him-5, and him-8, we compared body proportions and composition, and aspects of carbohydrate metabolism and gene expression between the C. elegans sexes in three adult stages. In all experiments, both sexes were grown on the same plate and separated using flow cytometry. The fat to fat-free mass ratio and the body volume-adjusted fat mass is similar between the sexes, although the body size is more than 50% smaller in adult males than in age-matched hermaphrodites. The volume-adjusted total RNA content is approximately 2-fold lower in males. Biochemical and NMR-based analyses reveal higher trehalose levels and much lower glucose levels in males than in hermaphrodites. The resulting trehalose-to-glucose ratio is 5.4-fold higher in males. These sex differences are reflected in gene expression data because the genes encoding key enzymes of the glycolysis and trehalose synthesis pathways are more highly expressed in males than in hermaphrodites. Notably, expression of the phosphofructokinase gene (C50F4.2) is 29-fold higher in males. Comparative analysis of gene expression data identifies 285 male-specific and 160 hermaphrodite-specific genes. These include transcription factor and C-type lectin-encoding genes. More than 35% of all C-type lectin genes are more highly expressed in males. The expression of many C-type lectin genes differs by a factor of >100 between the sexes. In conclusion, we found sex differences in carbohydrate metabolism that are linked to gene expression and identified certain lectin genes that are differentially expressed by the C. elegans sexes.
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Affiliation(s)
- Claudia Miersch
- Department of Molecular Prevention, Institute of Human Nutrition and Food Science, Christian-Albrechts-University of Kiel, Kiel, Germany
| | - Frank Döring
- Department of Molecular Prevention, Institute of Human Nutrition and Food Science, Christian-Albrechts-University of Kiel, Kiel, Germany
- * E-mail:
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78
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Smith JR, Stanfield GM. A seminal fluid protease activates sperm motility in C. elegans males. WORM 2012; 1:151-4. [PMID: 24058840 PMCID: PMC3670406 DOI: 10.4161/worm.19502] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Accepted: 01/26/2012] [Indexed: 01/13/2023]
Abstract
Seminal fluid factors have been shown to play a significant role in fertility in many animals. However, little is known about the contributions of seminal fluid to male fertility in C. elegans. In this commentary, we summarize our recent finding of a seminal fluid sperm activator, the serine protease TRY-5. TRY-5 is required for males to activate sperm, yet surprisingly it is not required for male fertility, likely due to redundancy with an activator present in hermaphrodites. TRY-5 is transferred to hermaphrodites during mating in a series of distinct release events just prior to transfer of sperm. Thus, we propose a model in which TRY-5 cleaves sperm cell surface proteins to trigger sperm maturation. We discuss other possible roles for seminal fluid factors in C. elegans and prospects for using TRY-5 as a marker for studies of male mating behavior and seminal fluid secretion.
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Affiliation(s)
- Joseph R. Smith
- Department of Human Genetics; University of Utah; Salt Lake City, UT USA
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79
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Thomas CG, Woodruff GC, Haag ES. Causes and consequences of the evolution of reproductive mode in Caenorhabditis nematodes. Trends Genet 2012; 28:213-20. [PMID: 22480920 DOI: 10.1016/j.tig.2012.02.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2011] [Revised: 02/24/2012] [Accepted: 02/27/2012] [Indexed: 12/12/2022]
Abstract
Reproduction is directly connected to the suite of developmental and physiological mechanisms that enable it, but how it occurs also has consequences for the genetics, ecology and longer term evolutionary potential of a lineage. In the nematode Caenorhabditis elegans, anatomically female XX worms can self-fertilize their eggs. This ability evolved recently and in multiple Caenorhabditis lineages from male-female ancestors, providing a model for examining both the developmental causes and longer term consequences of a novel, convergently evolved reproductive mode. Here, we review recent work that implicates translation control in the evolution of XX spermatogenesis, with different selfing lineages possessing both reproducible and idiosyncratic features. We also discuss the consequences of selfing, which leads to a rapid loss of variation and relaxation of natural and sexual selection on mating-related traits, and may ultimately put selfing lineages at a higher risk of extinction.
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Affiliation(s)
- Cristel G Thomas
- Department of Biology, University of Maryland, College Park, MD 20742, USA
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80
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Shifferman EM. It's all in your head: the role of quantity estimation in sperm competition. Proc Biol Sci 2012; 279:833-40. [PMID: 22171084 PMCID: PMC3259941 DOI: 10.1098/rspb.2011.2256] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2011] [Accepted: 11/25/2011] [Indexed: 11/12/2022] Open
Abstract
The study of animal cognition has provided valuable data throughout the years, yet its reliance on laboratory work leaves some open questions. The main question is whether animals employ cognition in daily decision-making. The following discussion uses sperm competition (SC) as a test case for demonstrating the effect of cognition on routine choices, in this case, sexual selection. Cognition is manifested here by males' ability to represent the number of rivals competing with them. I claim that response to SC is driven by quantity estimation and the ability to assess competition magnitude cognitively. Hence, cognition can determine males' response to SC, and consequentially it can be selected within this context. This supports the argument that cognition constitutes an integral part of an individual's toolbox in solving real-life problems, and shows that physical and behavioural phenomena can expose cognition to selection and facilitate its evolution.
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Affiliation(s)
- Eran M Shifferman
- Konrad Lorenz Institute for Evolution and Cognition Research, Adolf Lorenz Gasse 2, 3422 Altenberg, Austria.
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81
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Nematode sperm maturation triggered by protease involves sperm-secreted serine protease inhibitor (Serpin). Proc Natl Acad Sci U S A 2012; 109:1542-7. [PMID: 22307610 DOI: 10.1073/pnas.1109912109] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Spermiogenesis is a series of poorly understood morphological, physiological and biochemical processes that occur during the transition of immotile spermatids into motile, fertilization-competent spermatozoa. Here, we identified a Serpin (serine protease inhibitor) family protein (As_SRP-1) that is secreted from spermatids during nematode Ascaris suum spermiogenesis (also called sperm activation) and we showed that As_SRP-1 has two major functions. First, As_SRP-1 functions in cis to support major sperm protein (MSP)-based cytoskeletal assembly in the spermatid that releases it, thereby facilitating sperm motility acquisition. Second, As_SRP-1 released from an activated sperm inhibits, in trans, the activation of surrounding spermatids by inhibiting vas deferens-derived As_TRY-5, a trypsin-like serine protease necessary for sperm activation. Because vesicular exocytosis is necessary to create fertilization-competent sperm in many animal species, components released during this process might be more important modulators of the physiology and behavior of surrounding sperm than was previously appreciated.
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82
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Ruan QL, Ju JJ, Li YH, Li XB, Liu R, Liang GY, Zhang J, Pu YP, Wang DY, Yin LH. Chlorpyrifos exposure reduces reproductive capacity owing to a damaging effect on gametogenesis in the nematode Caenorhabditis elegans. J Appl Toxicol 2011; 32:527-35. [PMID: 22180373 DOI: 10.1002/jat.1783] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2011] [Revised: 11/04/2011] [Accepted: 11/04/2011] [Indexed: 12/22/2022]
Abstract
Previous studies have revealed that chlorpyrifos exposure adversely affects the reproductive capacity of male rodents. The present study investigated the reproductive toxicity of chlorpyrifos exposure and possible related mechanisms using the nematode Caenorhabditis elegans. L4 nematode larvae were exposed to chlorpyrifos at concentrations of 0.003, 0.03, 0.3 and 3.0 mg l(-1) for different durations. In addition to decreased brood size, reduced spermatid size, increased percentage of abnormal spermatids, suppressed spermatid activation and motility of sperm, damaged oocyte morphology, increased numbers of apoptotic cells and unfertilized oocytes were observed in nematodes exposed to various concentrations of chlorpyrifos. Moreover, expression patterns of the genes spe-10, spe-15, fer-1, prg-1, glp-1, mlh-1, cyb-3, ced-3, ced-4 and ced-9 (which are associated with spermatid size, spermatid activation and morphology, oocyte morphology, oocyte function, and apoptosis) were altered after chlorpyrifos exposure. Therefore, chlorpyrifos exposure may adversely affect fertility in nematodes by influencing both spermatogenesis and oogenesis. Alterations in the expression patterns of genes involved in gametogenesis may explain the corresponding changes in gametogenesis in nematodes exposed to chlorpyrifos. Hence, the model organism Caenorhabditis elegans is recommended for assessment of reproductive toxicity relating to gametogenesis.
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Affiliation(s)
- Qin-Li Ruan
- Key Laboratory of Environmental Medicine Engineering in Ministry of Education, Department of Occupational and Environmental Health, School of Public Health, Southeast University, Nanjing, China
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83
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Sperm development and motility are regulated by PP1 phosphatases in Caenorhabditis elegans. Genetics 2011; 190:143-57. [PMID: 22042574 DOI: 10.1534/genetics.111.135376] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Sperm from different species have evolved distinctive motility structures, including tubulin-based flagella in mammals and major sperm protein (MSP)-based pseudopods in nematodes. Despite such divergence, we show that sperm-specific PP1 phosphatases, which are required for male fertility in mouse, function in multiple processes in the development and motility of Caenorhabditis elegans amoeboid sperm. We used live-imaging analysis to show the PP1 phosphatases GSP-3 and GSP-4 (GSP-3/4) are required to partition chromosomes during sperm meiosis. Postmeiosis, tracking fluorescently labeled sperm revealed that both male and hermaphrodite sperm lacking GSP-3/4 are immotile. Genetic and in vitro activation assays show lack of GSP-3/4 causes defects in pseudopod development and the rate of pseudopodial treadmilling. Further, GSP-3/4 are required for the localization dynamics of MSP. GSP-3/4 shift localization in concert with MSP from fibrous bodies that sequester MSP at the base of the pseudopod, where directed MSP disassembly facilitates pseudopod contraction. Consistent with a role for GSP-3/4 as a spatial regulator of MSP disassembly, MSP is mislocalized in sperm lacking GSP-3/4. Although a requirement for PP1 phosphatases in nematode and mammalian sperm suggests evolutionary conservation, we show PP1s have independently evolved sperm-specific paralogs in separate lineages. Thus PP1 phosphatases are highly adaptable and employed across a broad range of sexually reproducing species to regulate male fertility.
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84
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Gómez Montoto L, Varea Sánchez M, Tourmente M, Martín-Coello J, Luque-Larena JJ, Gomendio M, Roldan ERS. Sperm competition differentially affects swimming velocity and size of spermatozoa from closely related muroid rodents: head first. Reproduction 2011; 142:819-30. [PMID: 21954130 DOI: 10.1530/rep-11-0232] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Sperm competition favours an increase in sperm swimming velocity that maximises the chances that sperm will reach the ova before rival sperm and fertilise. Comparative studies have shown that the increase in sperm swimming speed is associated with an increase in total sperm size. However, it is not known which are the first evolutionary steps that lead to increases in sperm swimming velocity. Using a group of closely related muroid rodents that differ in levels of sperm competition, we here test the hypothesis that subtle changes in sperm design may represent early evolutionary changes that could make sperm swim faster. Our findings show that as sperm competition increases so does sperm swimming speed. Sperm swimming velocity is associated with the size of all sperm components. However, levels of sperm competition are only related to an increase in sperm head area. Such increase is a consequence of an increase in the length of the sperm head, and also of the presence of an apical hook in some of the species studied. These findings suggest that the presence of a hook may modify the sperm head in such a way that would help sperm swim faster and may also be advantageous if sperm with larger heads are better able to attach to the epithelial cells lining the lower isthmus of the oviduct where sperm remain quiescent before the final race to reach the site of fertilisation.
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Affiliation(s)
- Laura Gómez Montoto
- Reproductive Ecology and Biology Group, Museo Nacional de Ciencias Naturales (CSIC), Madrid, Spain
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85
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Murray RL, Cutter AD. Experimental evolution of sperm count in protandrous self-fertilizing hermaphrodites. ACTA ACUST UNITED AC 2011; 214:1740-7. [PMID: 21525321 DOI: 10.1242/jeb.053181] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Sperm count evolution is driven by sexual selection, with an added role of selection on gamete resource allocation for hermaphrodite spermatogenesis. However, self-fertilization by hermaphrodites retards sexual selection and results in the evolution of reduced investment in sperm or pollen. In contrast to reproduction limited by female gametes (Bateman's Principle), self-fertilizing Caenorhabditis elegans hermaphrodites exhibit sperm-limited reproduction. Caenorhabditis elegans hermaphrodites are thought to experience a fitness trade-off between lifetime fecundity and generation time: longer sperm production decreases the risk of self-sperm depletion, but at the same time delays the onset of selfing and thus increases egg-to-egg generation time. Theory predicts that shorter larval development will favor lower sperm counts and longer development will favor more sperm. To investigate how developmental trajectories affect the evolution of sperm production, we performed experimental evolution by directly competing alleles controlling hermaphrodite sperm count, conducted under different environmental conditions that alter development time. Results are partially consistent with theory: rapid larval development generally favored alleles encoding production of few sperm. However, we identify some previously unrecognized simplifications of the theory and its application to our experimental system. In addition, we evaluated the generality of sperm limitation in C. elegans. Although optimal growth conditions yield sperm limitation, non-optimal conditions induce oocyte limitation, suggesting that this species might conform to Bateman's Principle under many natural settings. These findings demonstrate how developmental trajectories can shape the fitness landscape for the evolution of reproduction and sperm traits, even without sexual selection.
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Affiliation(s)
- Rosalind L Murray
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON M5S3B2, Canada
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86
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Baldi C, Viviano J, Ellis RE. A bias caused by ectopic development produces sexually dimorphic sperm in nematodes. Curr Biol 2011; 21:1416-20. [PMID: 21835620 DOI: 10.1016/j.cub.2011.07.034] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2011] [Revised: 06/07/2011] [Accepted: 07/21/2011] [Indexed: 10/17/2022]
Abstract
Self-fertile hermaphrodites have evolved independently several times in the genus Caenorhabditis [1, 2]. These XX hermaphrodites make smaller sperm than males [3, 4], which they use to fertilize their own oocytes. Because larger sperm outcompete smaller sperm in nematodes [3-5], it had been assumed that this dimorphism evolved in response to sperm competition. However, we show that it was instead caused by a developmental bias. When we transformed females of the species Caenorhabditis remanei into hermaphrodites [6], their sperm were significantly smaller than those of males. Because this species never makes hermaphrodites in the wild, this dimorphism cannot be due to selection. Instead, analyses of the related nematode Caenorhabditis elegans suggest that this dimorphism might reflect the development of sperm within the distinct physiological environment of the hermaphrodite gonad. These results reveal a new mechanism for some types of developmental bias-the effects of a novel physical location alter the development of ectopic cells in predictable ways.
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Affiliation(s)
- Christopher Baldi
- Graduate School of Biomedical Sciences, The UMDNJ School of Osteopathic Medicine, B303 Science Center, 2 Medical Center Drive, Stratford, NJ 08084, USA
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87
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Iwata Y, Shaw P, Fujiwara E, Shiba K, Kakiuchi Y, Hirohashi N. Why small males have big sperm: dimorphic squid sperm linked to alternative mating behaviours. BMC Evol Biol 2011; 11:236. [PMID: 21831296 PMCID: PMC3176235 DOI: 10.1186/1471-2148-11-236] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2011] [Accepted: 08/10/2011] [Indexed: 11/25/2022] Open
Abstract
Background Sperm cells are the target of strong sexual selection that may drive changes in sperm structure and function to maximize fertilisation success. Sperm evolution is regarded to be one of the major consequences of sperm competition in polyandrous species, however it can also be driven by adaptation to the environmental conditions at the site of fertilization. Strong stabilizing selection limits intra-specific variation, and therefore polymorphism, among fertile sperm (eusperm). Here we analyzed reproductive morphology differences among males employing characteristic alternative mating behaviours, and so potentially different conditions of sperm competition and fertilization environment, in the squid Loligo bleekeri. Results Large consort males transfer smaller (average total length = 73 μm) sperm to a female's internal sperm storage location, inside the oviduct; whereas small sneaker males transfer larger (99 μm) sperm to an external location around the seminal receptacle near the mouth. No significant difference in swimming speed was observed between consort and sneaker sperm. Furthermore, sperm precedence in the seminal receptacle was not biased toward longer sperm, suggesting no evidence for large sperm being favoured in competition for space in the sperm storage organ among sneaker males. Conclusions Here we report the first case, in the squid Loligo bleekeri, where distinctly dimorphic eusperm are produced by different sized males that employ alternative mating behaviours. Our results found no evidence that the distinct sperm dimorphism was driven by between- and within-tactic sperm competition. We propose that presence of alternative fertilization environments with distinct characteristics (i.e. internal or external), whether or not in combination with the effects of sperm competition, can drive the disruptive evolution of sperm size.
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Affiliation(s)
- Yoko Iwata
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Penglais, Aberystwyth, SY23 3DA, UK.
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Seidel HS, Ailion M, Li J, van Oudenaarden A, Rockman MV, Kruglyak L. A novel sperm-delivered toxin causes late-stage embryo lethality and transmission ratio distortion in C. elegans. PLoS Biol 2011; 9:e1001115. [PMID: 21814493 PMCID: PMC3144186 DOI: 10.1371/journal.pbio.1001115] [Citation(s) in RCA: 124] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2010] [Accepted: 06/16/2011] [Indexed: 12/25/2022] Open
Abstract
The evolutionary fate of an allele ordinarily depends on its contribution to host fitness. Occasionally, however, genetic elements arise that are able to gain a transmission advantage while simultaneously imposing a fitness cost on their hosts. We previously discovered one such element in C. elegans that gains a transmission advantage through a combination of paternal-effect killing and zygotic self-rescue. Here we demonstrate that this element is composed of a sperm-delivered toxin, peel-1, and an embryo-expressed antidote, zeel-1. peel-1 and zeel-1 are located adjacent to one another in the genome and co-occur in an insertion/deletion polymorphism. peel-1 encodes a novel four-pass transmembrane protein that is expressed in sperm and delivered to the embryo via specialized, sperm-specific vesicles. In the absence of zeel-1, sperm-delivered PEEL-1 causes lethal defects in muscle and epidermal tissue at the 2-fold stage of embryogenesis. zeel-1 is expressed transiently in the embryo and encodes a novel six-pass transmembrane domain fused to a domain with sequence similarity to zyg-11, a substrate-recognition subunit of an E3 ubiquitin ligase. zeel-1 appears to have arisen recently, during an expansion of the zyg-11 family, and the transmembrane domain of zeel-1 is required and partially sufficient for antidote activity. Although PEEL-1 and ZEEL-1 normally function in embryos, these proteins can act at other stages as well. When expressed ectopically in adults, PEEL-1 kills a variety of cell types, and ectopic expression of ZEEL-1 rescues these effects. Our results demonstrate that the tight physical linkage between two novel transmembrane proteins has facilitated their co-evolution into an element capable of promoting its own transmission to the detriment of organisms carrying it.
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Affiliation(s)
- Hannah S. Seidel
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, United States of America
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, United States of America
| | - Michael Ailion
- Department of Biology, University of Utah, Salt Lake City, Utah, United States of America
| | - Jialing Li
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Alexander van Oudenaarden
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Matthew V. Rockman
- Department of Biology, New York University, New York, New York, United States of America
- Center for Genomics and Systems Biology, New York University, New York, New York, United States of America
| | - Leonid Kruglyak
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, United States of America
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, United States of America
- Howard Hughes Medical Institute, Chevy Chase, Maryland, United States of America
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89
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Martel V, Darrouzet E, Boivin G. Phenotypic plasticity in the reproductive traits of a parasitoid. JOURNAL OF INSECT PHYSIOLOGY 2011; 57:682-687. [PMID: 21320506 DOI: 10.1016/j.jinsphys.2011.01.018] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2010] [Revised: 01/18/2011] [Accepted: 01/19/2011] [Indexed: 05/30/2023]
Abstract
Organisms show phenotypic plasticity--the capacity for a given genotype to express different phenotypes--in response to changes in the environment. Among the several factors that can cause phenotypic plasticity, nutritional constraints during development can affect the size of organisms and, consequently, affect most life-history traits, including reproductive traits. As their larvae are restricted by the amount of food contained in their host, parasitoids are a good model to study phenotypic plasticity related to size. The phenotypic plasticity of reproductive traits was investigated in the egg parasitoid Trichogramma euproctidis (Hymenoptera: Trichogrammatidae) by using host species of different sizes. Adult size, sperm storage organs (seminal vesicles and spermatheca), number of sperm stored and gamete size (sperm and oocyte) are all influenced by the host species; larger individuals have larger organs which contain more sperm, and both sperm and oocytes are correlated with adult size. However, while females become larger than males and mature larger oocytes in larger hosts, increase in sperm length stops after a given threshold.
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Affiliation(s)
- Véronique Martel
- Horticultural Research and Development Centre, Agriculture and Agri-Food Canada, 430 Boul. Gouin, St-Jean-sur-Richelieu, Québec J3B3E6, Canada.
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90
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Murray RL, Kozlowska JL, Cutter AD. Heritable determinants of male fertilization success in the nematode Caenorhabditis elegans. BMC Evol Biol 2011; 11:99. [PMID: 21492473 PMCID: PMC3096603 DOI: 10.1186/1471-2148-11-99] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2010] [Accepted: 04/14/2011] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Sperm competition is a driving force in the evolution of male sperm characteristics in many species. In the nematode Caenorhabditis elegans, larger male sperm evolve under experimentally increased sperm competition and larger male sperm outcompete smaller hermaphrodite sperm for fertilization within the hermaphrodite reproductive tract. To further elucidate the relative importance of sperm-related traits that contribute to differential reproductive success among males, we quantified within- and among-strain variation in sperm traits (size, rate of production, number transferred, competitive ability) for seven male genetic backgrounds known previously to differ with respect to some sperm traits. We also quantified male mating ability in assays for rates of courtship and successful copulation, and then assessed the roles of these pre- and post-mating traits in first- and second-male fertilization success. RESULTS We document significant variation in courtship ability, mating ability, sperm size and sperm production rate. Sperm size and production rate were strong indicators of early fertilization success for males that mated second, but male genetic backgrounds conferring faster sperm production make smaller sperm, despite virgin males of all genetic backgrounds transferring indistinguishable numbers of sperm to mating partners. CONCLUSIONS We have demonstrated that sperm size and the rate of sperm production represent dominant factors in determining male fertilization success and that C. elegans harbors substantial heritable variation for traits contributing to male reproductive success. C. elegans provides a powerful, tractable system for studying sexual selection and for dissecting the genetic basis and evolution of reproduction-related traits.
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Affiliation(s)
- Rosalind L Murray
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, M5S 3B2, Ontario, Canada
- School of Biological and Environmental Sciences, University of Stirling, Stirling, FK9 4LA, UK
| | - Joanna L Kozlowska
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, M5S 3B2, Ontario, Canada
| | - Asher D Cutter
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, M5S 3B2, Ontario, Canada
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91
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Lüpold S, Wistuba J, Damm OS, Rivers JW, Birkhead TR. Sperm competition leads to functional adaptations in avian testes to maximize sperm quantity and quality. Reproduction 2011; 141:595-605. [PMID: 21307271 DOI: 10.1530/rep-10-0501] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The outcome of sperm competition (i.e. competition for fertilization between ejaculates from different males) is primarily determined by the relative number and quality of rival sperm. Therefore, the testes are under strong selection to maximize both sperm number and quality, which are likely to result in trade-offs in the process of spermatogenesis (e.g. between the rate of spermatogenesis and sperm length or sperm energetics). Comparative studies have shown positive associations between the level of sperm competition and both relative testis size and the proportion of seminiferous (sperm-producing) tissue within the testes. However, it is unknown how the seminiferous tissue itself or the process of spermatogenesis might evolve in response to sperm competition. Therefore, we quantified the different germ cell types and Sertoli cells (SC) in testes to assess the efficiency of sperm production and its associations with sperm length and mating system across 10 species of New World Blackbirds (Icteridae) that show marked variation in sperm length and sperm competition level. We found that species under strong sperm competition generate more round spermatids (RS)/spermatogonium and have SC that support a greater number of germ cells, both of which are likely to increase the maximum sperm output. However, fewer of the RS appeared to elongate to mature spermatozoa in these species, which might be the result of selection for discarding spermatids with undesirable characteristics as they develop. Our results suggest that, in addition to overall size and gross morphology, testes have also evolved functional adaptations to maximize sperm quantity and quality.
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Affiliation(s)
- Stefan Lüpold
- Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield S10 2TN, UK.
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92
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Schärer L, Littlewood DTJ, Waeschenbach A, Yoshida W, Vizoso DB. Mating behavior and the evolution of sperm design. Proc Natl Acad Sci U S A 2011; 108:1490-5. [PMID: 21220334 PMCID: PMC3029721 DOI: 10.1073/pnas.1013892108] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Sperm are the most diverse of all animal cell types, and much of the diversity in sperm design is thought to reflect adaptations to the highly variable conditions under which sperm function and compete to achieve fertilization. Recent work has shown that these conditions often evolve rapidly as a consequence of multiple mating, suggesting a role for sexual selection and sexual conflict in the evolution of sperm design. However, very little of the striking diversity in sperm design is understood functionally, particularly in internally fertilizing organisms. We use phylogenetic comparative analyses covering 16 species of the hermaphroditic flatworm genus Macrostomum to show that a complex sperm design is associated with reciprocal mating and that this complexity is lost secondarily when hypodermic insemination--sperm injection through the epidermis--evolves. Specifically, the complex sperm design, which includes stiff lateral bristles, is likely a male persistence trait associated with sexual conflicts over the fate of received ejaculates and linked to female resistance traits, namely an intriguing postcopulatory sucking behavior and a thickened epithelium of the sperm-receiving organ. Our results suggest that the interactions between sperm donor, sperm, and sperm recipient can change drastically when hypodermic insemination evolves, involving convergent evolution of a needle-like copulatory organ, a simpler sperm design, and a simpler female genital morphology. Our study documents that a shift in the mating behavior may alter fundamentally the conditions under which sperm compete and thereby lead to a drastic change in sperm design.
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Affiliation(s)
- Lukas Schärer
- Evolutionary Biology, Zoological Institute, University of Basel, 4051 Basel, Switzerland.
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93
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Abstract
Although the general events surrounding fertilization in many species are well described, the molecular underpinnings of fertilization are still poorly understood. Caenorhabditis elegans has emerged as a powerful model system for addressing the molecular and cell biological mechanism of fertilization. A primary advantage is the ability to isolate and propagate mutants that effect gametes and no other cells. This chapter provides conceptual guidelines for the identification, maintenance, and experimental approaches for the study fertility mutants.
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Affiliation(s)
- Brian D. Geldziler
- Waksman Institute, Rutgers University, Dept. of Microbiology and Molecular Genetics
| | - Matthew R. Marcello
- Waksman Institute, Rutgers University, Dept. of Microbiology and Molecular Genetics
| | | | - Andrew Singson
- Waksman Institute, Rutgers University, Dept. of Microbiology and Molecular Genetics
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94
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Sperm number and velocity affect sperm competition success in the guppy (Poecilia reticulata). Behav Ecol Sociobiol 2010. [DOI: 10.1007/s00265-010-1085-y] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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95
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Wu TF, Nera B, Chu DS, Shakes DC. Elucidating gene regulatory mechanisms for sperm function through the integration of classical and systems approaches in C. elegans. Syst Biol Reprod Med 2010; 56:222-35. [PMID: 20536322 DOI: 10.3109/19396361003749986] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
From worms to mammals, successful spermatogenesis depends on a gene expression profile that balances activating and repressive mechanisms. Besides developmental control of specific spermatogenic genes, male fertility requires temporal shifts in global gene expression and dramatic changes in chromatin structure and condensation. Recent studies are beginning to elucidate the molecular processes that both drive these temporal changes in gene expression and underlie fertility. In this review, we provide an overview of relevant C. elegans studies that have laid the groundwork for modern approaches. Next, we highlight recent studies that investigate how gene expression in C. elegans is modulated during spermatogenesis. These studies use large-scale genomic profiling in combination with bioinformatics, genetics, biochemistry, and in vitro methods to target specific stages or processes during sperm formation. Such studies are beginning to elucidate the multiple layers of gene regulation required during spermatogenesis, i.e., transcriptional, post-transcriptional, and epigenetic. Moreover, knowledge of how C. elegans coordinately regulates gene expression during spermatogenesis promises to provide key insights into parallel processes in mammals that are vital for fertility.
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Affiliation(s)
- Tammy F Wu
- Department of Biology, San Francisco State University, San Francisco, CA 94132, USA
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96
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Nishimura H, L'Hernault SW. Spermatogenesis-defective (spe) mutants of the nematode Caenorhabditis elegans provide clues to solve the puzzle of male germline functions during reproduction. Dev Dyn 2010; 239:1502-14. [PMID: 20419782 DOI: 10.1002/dvdy.22271] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
In most species, each sex produces gametes, usually either sperm or oocytes, from its germline during gametogenesis. The sperm and oocyte subsequently fuse together during fertilization to create the next generation. This review focuses on spermatogenesis and the roles of sperm during fertilization in the nematode Caenorhabditis elegans, where suitable mutants are readily obtained. So far, 186 mutants defective in the C. elegans male germline functions have been isolated, and many of these mutations are alleles for one of the approximately 60 spermatogenesis-defective (spe) genes. Many cloned spe genes are expressed specifically in the male germline, where they play roles during spermatogenesis (spermatid production), spermiogenesis (spermatid activation into spermatozoa), and/or fertilization. Moreover, several spe genes are orthologs of mammalian genes, suggesting that the reproductive processes of the C. elegans and the mammalian male germlines might share common pathways at the molecular level.
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Affiliation(s)
- Hitoshi Nishimura
- Department of Biology, Emory University, Atlanta, Georgia 30322, USA
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97
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Smith CC, Ryan MJ. Evolution of sperm quality but not quantity in the internally fertilized fish Xiphophorus nigrensis. J Evol Biol 2010; 23:1759-71. [PMID: 20626545 DOI: 10.1111/j.1420-9101.2010.02041.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Species with alternative reproductive strategies are characterized by discrete differences among males in suites of traits related to competition for fertilizations. Models predict sneaker males should allocate more resources to their ejaculates because they experience sperm competition more frequently and often occupy a disfavoured 'role' owing to subordinance in intramale competition and female preferences for larger males. We examined whether sperm number and quality differed between male strategies in the internally fertilized fish Xiphophorus nigrensis and explored the relationship between sperm morphology and performance. We found sneaker males had similar testes sizes compared to courting males but ejaculates with both more viable and longer lived sperm. Sneaker sperm also had longer midpieces, which was positively correlated with both velocity and longevity. Our study suggests that the evolution of sperm quantity and quality can be decoupled and that the sperm morphology is likely to play an important role in mediating sperm competition through its effects on sperm performance.
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Affiliation(s)
- C C Smith
- University of Texas at Austin, Section of Integrative Biology, Austin, TX 78712, USA.
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98
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ELGEE KE, EVANS JP, RAMNARINE IW, RUSH SA, PITCHER TE. Geographic variation in sperm traits reflects predation risk and natural rates of multiple paternity in the guppy. J Evol Biol 2010; 23:1331-8. [DOI: 10.1111/j.1420-9101.2010.01996.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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99
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Austin MU, Liau WS, Balamurugan K, Ashokkumar B, Said HM, LaMunyon CW. Knockout of the folate transporter folt-1 causes germline and somatic defects in C. elegans. BMC DEVELOPMENTAL BIOLOGY 2010; 10:46. [PMID: 20441590 PMCID: PMC2874772 DOI: 10.1186/1471-213x-10-46] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/26/2010] [Accepted: 05/04/2010] [Indexed: 12/02/2022]
Abstract
BACKGROUND The C. elegans gene folt-1 is an ortholog of the human reduced folate carrier gene. The FOLT-1 protein has been shown to transport folate and to be involved in uptake of exogenous folate by worms. A knockout mutation of the gene, folt-1(ok1460), was shown to cause sterility, and here we investigate the source of the sterility and the effect of the folt-1 knockout on somatic function. RESULTS Our results show that folt-1(ok1460) knockout hermaphrodites have a substantially reduced germline, generate a small number of functional sperm, and only rarely produce a functional oocyte. We found no evidence of increased apoptosis in the germline of folt-1 knockout mutants, suggesting that germline proliferation is defective. While folt-1 knockout males are fertile, their rate of spermatogenesis was severely diminished, and the males were very poor maters. The mating defect is likely due to compromised metabolism and/or other somatic functions, as folt-1 knockout hermaphrodites displayed a shortened lifespan and elongated defecation intervals. CONCLUSIONS The FOLT-1 protein function affects both the soma and the germline. folt-1(ok1460) hermaphrodites suffer severely diminished lifespan and germline defects that result in sterility. Germline defects associated with folate deficiency appear widespread in animals, being found in humans, mice, fruit flies, and here, nematodes.
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Affiliation(s)
- Misa U Austin
- Department of Biological Sciences, California State University Pomona, CA 91768, USA
| | - Wei-Siang Liau
- Department of Biological Sciences, California State University Pomona, CA 91768, USA
- Current Address: Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA
| | - Krishnaswamy Balamurugan
- Veterans Affairs Medical Center, Long Beach, CA 90822, USA
- Departments of Medicine and Physiology/Biophysics, University of California, Irvine, CA 92697, USA
- Current Address: Department of Biotechnology, Alagappa University, Karaikudi 630 003, India
| | - Balasubramaniem Ashokkumar
- Veterans Affairs Medical Center, Long Beach, CA 90822, USA
- Departments of Medicine and Physiology/Biophysics, University of California, Irvine, CA 92697, USA
| | - Hamid M Said
- Veterans Affairs Medical Center, Long Beach, CA 90822, USA
- Departments of Medicine and Physiology/Biophysics, University of California, Irvine, CA 92697, USA
| | - Craig W LaMunyon
- Department of Biological Sciences, California State University Pomona, CA 91768, USA
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100
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Findlay GD, Swanson WJ. Proteomics enhances evolutionary and functional analysis of reproductive proteins. Bioessays 2010; 32:26-36. [PMID: 20020477 DOI: 10.1002/bies.200900127] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Reproductive proteins maintain species-specific barriers to fertilization, affect the outcome of sperm competition, mediate reproductive conflicts between the sexes, and potentially contribute to the formation of new species. However, the specific proteins and molecular mechanisms that underlie these processes are understood in only a handful of cases. Advances in genomic and proteomic technologies enable the identification of large suites of reproductive proteins, making it possible to dissect reproductive phenotypes at the molecular level. We first review these technological advances and describe how reproductive proteins are identified in diverse animal taxa. We then discuss the dynamic evolution of reproductive proteins and the potential selective forces that act on them. Finally, we describe molecular and genomic tools for functional analysis and detail how evolutionary data may be used to make predictions about interactions among reproductive proteins.
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Affiliation(s)
- Geoffrey D Findlay
- Department of Genome Sciences, University of Washington, Seattle, 98195-5065, USA.
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