1
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Abstract
Vertebrates exhibit a wide range of color patterns, which play critical roles in mediating intra- and interspecific communication. Because of their diversity and visual accessibility, color patterns offer a unique and fascinating window into the processes underlying biological organization. In this review, we focus on describing many of the general principles governing the formation and evolution of color patterns in different vertebrate groups. We characterize the types of patterns, review the molecular and developmental mechanisms by which they originate, and discuss their role in constraining or facilitating evolutionary change. Lastly, we outline outstanding questions in the field and discuss different approaches that can be used to address them. Overall, we provide a unifying conceptual framework among vertebrate systems that may guide research into naturally evolved mechanisms underlying color pattern formation and evolution.
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Affiliation(s)
| | - Ricardo Mallarino
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, USA;
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2
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Clark B, Kuwalekar M, Fischer B, Woltering J, Biran J, Juntti S, Kratochwil CF, Santos ME, Almeida MV. Genome editing in East African cichlids and tilapias: state-of-the-art and future directions. Open Biol 2023; 13:230257. [PMID: 38018094 PMCID: PMC10685126 DOI: 10.1098/rsob.230257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 10/27/2023] [Indexed: 11/30/2023] Open
Abstract
African cichlid fishes of the Cichlidae family are a group of teleosts important for aquaculture and research. A thriving research community is particularly interested in the cichlid radiations of the East African Great Lakes. One key goal is to pinpoint genetic variation underlying phenotypic diversification, but the lack of genetic tools has precluded thorough dissection of the genetic basis of relevant traits in cichlids. Genome editing technologies are well established in teleost models like zebrafish and medaka. However, this is not the case for emerging model organisms, such as East African cichlids, where these technologies remain inaccessible to most laboratories, due in part to limited exchange of knowledge and expertise. The Cichlid Science 2022 meeting (Cambridge, UK) hosted for the first time a Genome Editing Workshop, where the community discussed recent advances in genome editing, with an emphasis on CRISPR/Cas9 technologies. Based on the workshop findings and discussions, in this review we define the state-of-the-art of cichlid genome editing, share resources and protocols, and propose new possible avenues to further expand the cichlid genome editing toolkit.
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Affiliation(s)
- Bethan Clark
- Department of Zoology, University of Cambridge, Cambridge, UK
| | - Muktai Kuwalekar
- Helsinki Institute of Life Science (HiLIFE), University of Helsinki, Helsinki, Uusimaa 00014, Finland
- Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Uusimaa 00014, Finland
| | - Bettina Fischer
- Department of Genetics, University of Cambridge, Cambridge, UK
| | - Joost Woltering
- Zoology and Evolutionary Biology, Department of Biology, University of Konstanz, Konstanz, Baden-Württemberg 78457, Germany
| | - Jakob Biran
- Department of Poultry and Aquaculture, Institute of Animal Sciences, Agricultural Research Organization, Volcani Center, Rishon Lezion, Israel
| | - Scott Juntti
- Department of Biology, University of Maryland, College Park, MD, USA
| | - Claudius F. Kratochwil
- Helsinki Institute of Life Science (HiLIFE), University of Helsinki, Helsinki, Uusimaa 00014, Finland
- Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Uusimaa 00014, Finland
| | | | - Miguel Vasconcelos Almeida
- Department of Biochemistry, University of Cambridge, Cambridge, UK
- Wellcome/CRUK Gurdon Institute, University of Cambridge, Cambridge, UK
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3
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Santos ME, Lopes JF, Kratochwil CF. East African cichlid fishes. EvoDevo 2023; 14:1. [PMID: 36604760 PMCID: PMC9814215 DOI: 10.1186/s13227-022-00205-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 11/29/2022] [Indexed: 01/06/2023] Open
Abstract
Cichlid fishes are a very diverse and species-rich family of teleost fishes that inhabit lakes and rivers of India, Africa, and South and Central America. Research has largely focused on East African cichlids of the Rift Lakes Tanganyika, Malawi, and Victoria that constitute the biodiversity hotspots of cichlid fishes. Here, we give an overview of the study system, research questions, and methodologies. Research on cichlid fishes spans many disciplines including ecology, evolution, physiology, genetics, development, and behavioral biology. In this review, we focus on a range of organismal traits, including coloration phenotypes, trophic adaptations, appendages like fins and scales, sensory systems, sex, brains, and behaviors. Moreover, we discuss studies on cichlid phylogenies, plasticity, and general evolutionary patterns, ranging from convergence to speciation rates and the proximate and ultimate mechanisms underlying these processes. From a methodological viewpoint, the last decade has brought great advances in cichlid fish research, particularly through the advent of affordable deep sequencing and advances in genetic manipulations. The ability to integrate across traits and research disciplines, ranging from developmental biology to ecology and evolution, makes cichlid fishes a fascinating research system.
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Affiliation(s)
- M. Emília Santos
- grid.5335.00000000121885934Department of Zoology, University of Cambridge, Cambridge, UK
| | - João F. Lopes
- grid.7737.40000 0004 0410 2071Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki, Finland
| | - Claudius F. Kratochwil
- grid.7737.40000 0004 0410 2071Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki, Finland
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4
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Tyers AM, Cooke GM, Turner GF. Rare morph Lake Malawi mbuna cichlids benefit from reduced aggression from con- and hetero-specifics. J Evol Biol 2021; 34:1678-1690. [PMID: 34528321 DOI: 10.1111/jeb.13929] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 08/25/2021] [Accepted: 08/31/2021] [Indexed: 11/28/2022]
Abstract
Balancing selection is important for the maintenance of polymorphism as it can prevent either fixation of one morph through directional selection or genetic drift, or speciation by disruptive selection. Polychromatism, the presence of multiple genetically determined colour phenotypes, can be maintained if the fitness of alternative morphs depends on the relative frequency in a population. In aggressive species, negative frequency-dependent antagonism can prevent an increase in the frequency of rare morphs as they would only benefit from increased fitness while they are rare. Heterospecific aggression is common in nature and has the potential to contribute to rare morph advantage. Here we carry out field observations and laboratory aggression experiments with mbuna cichlids from Lake Malawi, to investigate the role of con- and heterospecific aggression in the maintenance of polychromatism and identify benefits to rare morphs which are likely to result from reduced aggression. We hypothesize that rare morph individuals receive less aggression than common morph individuals and therefore have an ecological advantage. Within species we found that males and females bias aggression towards their own morph, adding to the evidence that inherent own-morph aggression biases can contribute to balancing selection. Over-representation of rare morph territory owners may be influenced by two factors; higher tolerance of different morph individuals as neighbours, and the ability of rare morphs to spend more time feeding. Reduced aggression to rare morph individuals by heterospecifics may also contribute to rare morph advantage.
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Affiliation(s)
| | - Gavan M Cooke
- School of Biological Sciences, Bangor University, Bangor, UK
| | - George F Turner
- School of Biological Sciences, Bangor University, Bangor, UK
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5
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Patil C, Sylvester JB, Abdilleh K, Norsworthy MW, Pottin K, Malinsky M, Bloomquist RF, Johnson ZV, McGrath PT, Streelman JT. Genome-enabled discovery of evolutionary divergence in brains and behavior. Sci Rep 2021; 11:13016. [PMID: 34155279 PMCID: PMC8217251 DOI: 10.1038/s41598-021-92385-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 06/08/2021] [Indexed: 02/05/2023] Open
Abstract
Lake Malawi cichlid fishes exhibit extensive divergence in form and function built from a relatively small number of genetic changes. We compared the genomes of rock- and sand-dwelling species and asked which genetic variants differed among the groups. We found that 96% of differentiated variants reside in non-coding sequence but these non-coding diverged variants are evolutionarily conserved. Genome regions near differentiated variants are enriched for craniofacial, neural and behavioral categories. Following leads from genome sequence, we used rock- vs. sand-species and their hybrids to (i) delineate the push-pull roles of BMP signaling and irx1b in the specification of forebrain territories during gastrulation and (ii) reveal striking context-dependent brain gene expression during adult social behavior. Our results demonstrate how divergent genome sequences can predict differences in key evolutionary traits. We highlight the promise of evolutionary reverse genetics-the inference of phenotypic divergence from unbiased genome sequencing and then empirical validation in natural populations.
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Affiliation(s)
- Chinar Patil
- School of Biological Sciences and Petit Institute of Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA, USA.
| | - Jonathan B Sylvester
- School of Biological Sciences and Petit Institute of Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA, USA
- Department of Biology, Georgia State University, Atlanta, GA, USA
| | - Kawther Abdilleh
- School of Biological Sciences and Petit Institute of Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA, USA
| | - Michael W Norsworthy
- Catalog Technologies Inc., Boston, MA, USA
- Freedom of Form Foundation, Inc., Cambridge, MA, USA
| | - Karen Pottin
- Laboratoire de Biologie du Dévelopement (IBPS-LBD, UMR7622), CNRS, Institut de Biologie Paris Seine, Sorbonne Université, Paris, France
| | - Milan Malinsky
- Department of Environmental Sciences, Zoological Institute, University of Basel, Basel, Switzerland
- Wellcome Trust Sanger Institute, Cambridge, UK
| | - Ryan F Bloomquist
- School of Biological Sciences and Petit Institute of Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA, USA
- Department of Oral Biology and Diagnostic Sciences, Department of Restorative Sciences, Dental College of Georgia, Augusta University, Augusta, GA, USA
| | - Zachary V Johnson
- School of Biological Sciences and Petit Institute of Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA, USA
| | - Patrick T McGrath
- School of Biological Sciences and Petit Institute of Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA, USA
| | - Jeffrey T Streelman
- School of Biological Sciences and Petit Institute of Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA, USA
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6
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Jamie GA, Meier JI. The Persistence of Polymorphisms across Species Radiations. Trends Ecol Evol 2020; 35:795-808. [DOI: 10.1016/j.tree.2020.04.007] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 04/08/2020] [Accepted: 04/16/2020] [Indexed: 12/12/2022]
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7
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Baran NM, Streelman JT. Ecotype differences in aggression, neural activity and behaviorally relevant gene expression in cichlid fish. GENES BRAIN AND BEHAVIOR 2020; 19:e12657. [PMID: 32323443 DOI: 10.1111/gbb.12657] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 04/17/2020] [Accepted: 04/18/2020] [Indexed: 12/18/2022]
Abstract
In Lake Malawi, two ecologically distinct lineages of cichlid fishes (rock- vs sand-dwelling ecotypes, each comprised of over 200 species) evolved within the last million years. The rock-dwelling species (Mbuna) are aggressively territorial year-round and males court and spawn with females over rocky substrate. In contrast, males of sand-dwelling species are not territorial and instead aggregate on seasonal breeding leks in which males construct courtship "bowers" in the sand. However, little is known about how phenotypic variation in aggression is produced by the genome. In this study, we first quantify and compare behavior in seven cichlid species, demonstrating substantial ecotype and species differences in unconditioned mirror-elicited aggression. Second, we compare neural activity in mirror-elicited aggression in two representative species, Mchenga conophoros (sand-dwelling) and Petrotilapia chitimba (rock-dwelling). Finally, we compare gene expression patterns between these two species, specifically within neurons activated during mirror aggression. We identified a large number of genes showing differential expression in mirror-elicited aggression, as well as many genes that differ between ecotypes. These genes, which may underly species differences in behavior, include several neuropeptides, genes involved in the synthesis of steroid hormones and neurotransmitter activity. This work lays the foundation for future experiments using this emerging genetic model system to investigate the genomic basis of evolved species differences in both brain and behavior.
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Affiliation(s)
- Nicole M Baran
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA.,Department of Psychology, Emory University, Atlanta, Georgia, USA
| | - J Todd Streelman
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA.,The Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia, USA
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8
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Liang Y, Gerwin J, Meyer A, Kratochwil CF. Developmental and Cellular Basis of Vertical Bar Color Patterns in the East African Cichlid Fish Haplochromis latifasciatus. Front Cell Dev Biol 2020; 8:62. [PMID: 32117987 PMCID: PMC7026194 DOI: 10.3389/fcell.2020.00062] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2019] [Accepted: 01/22/2020] [Indexed: 12/13/2022] Open
Abstract
The East African adaptive radiations of cichlid fishes are renowned for their diversity in coloration. Yet, the developmental basis of pigment pattern formation remains largely unknown. One of the most common melanic patterns in cichlid fishes are vertical bar patterns. Here we describe the ontogeny of this conspicuous pattern in the Lake Kyoga species Haplochromis latifasciatus. Beginning with the larval stages we tracked the formation of this stereotypic color pattern and discovered that its macroscopic appearance is largely explained by an increase in melanophore density and accumulation of melanin during the first 3 weeks post-fertilization. The embryonal analysis is complemented with cytological quantifications of pigment cells in adult scales and the dermis beneath the scales. In adults, melanic bars are characterized by a two to threefold higher density of melanophores than in the intervening yellow interbars. We found no strong support for differences in other pigment cell types such as xanthophores. Quantitative PCRs for twelve known pigmentation genes showed that expression of melanin synthesis genes tyr and tyrp1a is increased five to sixfold in melanic bars, while xanthophore and iridophore marker genes are not differentially expressed. In summary, we provide novel insights on how vertical bars, one of the most widespread vertebrate color patterns, are formed through dynamic control of melanophore density, melanin synthesis and melanosome dispersal.
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Affiliation(s)
- Yipeng Liang
- Zoology and Evolutionary Biology, Department of Biology, University of Konstanz, Konstanz, Germany
| | - Jan Gerwin
- Zoology and Evolutionary Biology, Department of Biology, University of Konstanz, Konstanz, Germany
| | - Axel Meyer
- Zoology and Evolutionary Biology, Department of Biology, University of Konstanz, Konstanz, Germany
| | - Claudius F Kratochwil
- Zoology and Evolutionary Biology, Department of Biology, University of Konstanz, Konstanz, Germany
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9
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Abstract
Quantitative trait loci (QTL) are genetic regions that influence phenotypic variation of a complex trait, often through genetic interactions with each other and the environment. These are commonly identified through a statistical genetic analysis known as QTL mapping. Here, I present a step-by-step, practical approach to QTL mapping along with a sample data file. I focus on methods commonly used and discoveries that have been made in fishes, and utilize a multiple QTL mapping (MQM) approach in the free software package R/qtl.
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Affiliation(s)
- Kara E Powder
- Department of Biological Sciences, Clemson University, Clemson, SC, USA.
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10
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Abstract
The tremendous diversity of animal behaviors has inspired generations of scientists from an array of biological disciplines. To complement investigations of ecological and evolutionary factors contributing to behavioral evolution, modern sequencing, gene editing, computational and neuroscience tools now provide a means to discover the proximate mechanisms upon which natural selection acts to generate behavioral diversity. Social behaviors are motivated behaviors that can differ tremendously between closely related species, suggesting phylogenetic plasticity in their underlying biological mechanisms. In addition, convergent evolution has repeatedly given rise to similar forms of social behavior and mating systems in distantly related species. Social behavioral divergence and convergence provides an entry point for understanding the neurogenetic mechanisms contributing to behavioral diversity. We argue that the greatest strides in discovering mechanisms contributing to social behavioral diversity will be achieved through integration of interdisciplinary comparative approaches with modern tools in diverse species systems. We review recent advances and future potential for discovering mechanisms underlying social behavioral variation; highlighting patterns of social behavioral evolution, oxytocin and vasopressin neuropeptide systems, genetic/transcriptional "toolkits," modern experimental tools, and alternative species systems, with particular emphasis on Microtine rodents and Lake Malawi cichlid fishes.
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Affiliation(s)
- Zachary V Johnson
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Larry J Young
- Center for Translational Social Neuroscience, Silvio O. Conte Center for Oxytocin and Social Cognition, Department of Psychiatry and Behavioral Sciences, Yerkes National Primate Research Center, Emory University, Atlanta, Georgia, USA
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11
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Gammerdinger WJ, Kocher TD. Unusual Diversity of Sex Chromosomes in African Cichlid Fishes. Genes (Basel) 2018; 9:E480. [PMID: 30287777 PMCID: PMC6210639 DOI: 10.3390/genes9100480] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 09/26/2018] [Accepted: 10/01/2018] [Indexed: 11/30/2022] Open
Abstract
African cichlids display a remarkable assortment of jaw morphologies, pigmentation patterns, and mating behaviors. In addition to this previously documented diversity, recent studies have documented a rich diversity of sex chromosomes within these fishes. Here we review the known sex-determination network within vertebrates, and the extraordinary number of sex chromosomes systems segregating in African cichlids. We also propose a model for understanding the unusual number of sex chromosome systems within this clade.
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Affiliation(s)
- William J Gammerdinger
- Institute of Science and Technology (IST) Austria, Am Campus 1, 3400 Klosterneuburg, Austria.
| | - Thomas D Kocher
- Department of Biology, University of Maryland, College Park, MD 20742, USA.
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12
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Feulner PGD, Schwarzer J, Haesler MP, Meier JI, Seehausen O. A Dense Linkage Map of Lake Victoria Cichlids Improved the Pundamilia Genome Assembly and Revealed a Major QTL for Sex-Determination. G3 (BETHESDA, MD.) 2018; 8:2411-2420. [PMID: 29760203 PMCID: PMC6027883 DOI: 10.1534/g3.118.200207] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 05/13/2018] [Indexed: 01/09/2023]
Abstract
Genetic linkage maps are essential for comparative genomics, high quality genome sequence assembly and fine scale quantitative trait locus (QTL) mapping. In the present study we identified and genotyped markers via restriction-site associated DNA (RAD) sequencing and constructed a genetic linkage map based on 1,597 SNP markers of an interspecific F2 cross of two closely related Lake Victoria cichlids (Pundamilia pundamilia and P sp. 'red head'). The SNP markers were distributed on 22 linkage groups and the total map size was 1,594 cM with an average marker distance of 1.01 cM. This high-resolution genetic linkage map was used to anchor the scaffolds of the Pundamilia genome and estimate recombination rates along the genome. Via QTL mapping we identified a major QTL for sex in a ∼1.9 Mb region on Pun-LG10, which is homologous to Oreochromis niloticus LG 23 (Ore-LG23) and includes a well-known vertebrate sex-determination gene (amh).
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Affiliation(s)
- Philine G D Feulner
- Department of Fish Ecology and Evolution, Centre of Ecology, Evolution and Biogeochemistry, EAWAG Swiss Federal Institute of Aquatic Science and Technology, 6047 Kastanienbaum, Switzerland
- Division of Aquatic Ecology and Evolution, Institute of Ecology and Evolution, University of Bern, 3012 Switzerland
| | - Julia Schwarzer
- Department of Fish Ecology and Evolution, Centre of Ecology, Evolution and Biogeochemistry, EAWAG Swiss Federal Institute of Aquatic Science and Technology, 6047 Kastanienbaum, Switzerland
- Division of Aquatic Ecology and Evolution, Institute of Ecology and Evolution, University of Bern, 3012 Switzerland
- Zoologisches Forschungsmuseum Alexander Koenig, 53113 Bonn, Germany
| | - Marcel P Haesler
- Department of Fish Ecology and Evolution, Centre of Ecology, Evolution and Biogeochemistry, EAWAG Swiss Federal Institute of Aquatic Science and Technology, 6047 Kastanienbaum, Switzerland
- Division of Aquatic Ecology and Evolution, Institute of Ecology and Evolution, University of Bern, 3012 Switzerland
| | - Joana I Meier
- Department of Fish Ecology and Evolution, Centre of Ecology, Evolution and Biogeochemistry, EAWAG Swiss Federal Institute of Aquatic Science and Technology, 6047 Kastanienbaum, Switzerland
- Division of Aquatic Ecology and Evolution, Institute of Ecology and Evolution, University of Bern, 3012 Switzerland
| | - Ole Seehausen
- Department of Fish Ecology and Evolution, Centre of Ecology, Evolution and Biogeochemistry, EAWAG Swiss Federal Institute of Aquatic Science and Technology, 6047 Kastanienbaum, Switzerland
- Division of Aquatic Ecology and Evolution, Institute of Ecology and Evolution, University of Bern, 3012 Switzerland
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13
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The Colorful Sex Chromosomes of Teleost Fish. Genes (Basel) 2018; 9:genes9050233. [PMID: 29751562 PMCID: PMC5977173 DOI: 10.3390/genes9050233] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 04/24/2018] [Accepted: 04/24/2018] [Indexed: 12/14/2022] Open
Abstract
Teleost fish provide some of the most intriguing examples of sexually dimorphic coloration, which is often advantageous for only one of the sexes. Mapping studies demonstrated that the genetic loci underlying such color patterns are frequently in tight linkage to the sex-determining locus of a species, ensuring sex-specific expression of the corresponding trait. Several genes affecting color synthesis and pigment cell development have been previously described, but the color loci on the sex chromosomes have mostly remained elusive as yet. Here, we summarize the current knowledge about the genetics of such color loci in teleosts, mainly from studies on poeciliids and cichlids. Further studies on these color loci will certainly provide important insights into the evolution of sex chromosomes.
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14
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Henning F, Machado-Schiaffino G, Baumgarten L, Meyer A. Genetic dissection of adaptive form and function in rapidly speciating cichlid fishes. Evolution 2017; 71:1297-1312. [PMID: 28211577 DOI: 10.1111/evo.13206] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Accepted: 02/04/2017] [Indexed: 12/14/2022]
Abstract
Genes of major phenotypic effects and strong genetic correlations can facilitate adaptation, direct selective responses, and potentially lead to phenotypic convergence. However, the preponderance of this type of genetic architecture in repeatedly evolved adaptations remains unknown. Using hybrids between Haplochromis chilotes (thick-lipped) and Pundamilia nyererei (thin-lipped) we investigated the genetics underlying hypertrophied lips and elongated heads, traits that evolved repeatedly in cichlids. At least 25 loci of small-to-moderate and mainly additive effects were detected. Phenotypic variation in lip and head morphology was largely independent. Although several QTL overlapped for lip and head morphology traits, they were often of opposite effects. The distribution of effect signs suggests strong selection on lips. The fitness implications of several detected loci were demonstrated using a laboratory assay testing for the association between genotype and variation in foraging performance. The persistence of low fitness alleles in head morphology appears to be maintained through antagonistic pleiotropy/close linkage with positive-effect lip morphology alleles. Rather than being based on few major loci with strong positive genetic correlations, our results indicate that the evolution of the Lake Victoria thick-lipped ecomorph is the result of selection on numerous loci distributed throughout the genome.
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Affiliation(s)
- Frederico Henning
- Department of Biology, University of Konstanz, 78464, Konstanz, Germany.,Department of Genetics, CCS, Federal University of Rio de Janeiro, Ilha do Fundão, 21941-599, Rio de Janeiro, Brazil
| | | | - Lukas Baumgarten
- Department of Biology, University of Konstanz, 78464, Konstanz, Germany
| | - Axel Meyer
- Department of Biology, University of Konstanz, 78464, Konstanz, Germany
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15
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Bloomquist RF, Parnell NF, Phillips KA, Fowler TE, Yu TY, Sharpe PT, Streelman JT. Coevolutionary patterning of teeth and taste buds. Proc Natl Acad Sci U S A 2015; 112:E5954-62. [PMID: 26483492 PMCID: PMC4640805 DOI: 10.1073/pnas.1514298112] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Teeth and taste buds are iteratively patterned structures that line the oro-pharynx of vertebrates. Biologists do not fully understand how teeth and taste buds develop from undifferentiated epithelium or how variation in organ density is regulated. These organs are typically studied independently because of their separate anatomical location in mammals: teeth on the jaw margin and taste buds on the tongue. However, in many aquatic animals like bony fishes, teeth and taste buds are colocalized one next to the other. Using genetic mapping in cichlid fishes, we identified shared loci controlling a positive correlation between tooth and taste bud densities. Genome intervals contained candidate genes expressed in tooth and taste bud fields. sfrp5 and bmper, notable for roles in Wingless (Wnt) and bone morphogenetic protein (BMP) signaling, were differentially expressed across cichlid species with divergent tooth and taste bud density, and were expressed in the development of both organs in mice. Synexpression analysis and chemical manipulation of Wnt, BMP, and Hedgehog (Hh) pathways suggest that a common cichlid oral lamina is competent to form teeth or taste buds. Wnt signaling couples tooth and taste bud density and BMP and Hh mediate distinct organ identity. Synthesizing data from fish and mouse, we suggest that the Wnt-BMP-Hh regulatory hierarchy that configures teeth and taste buds on mammalian jaws and tongues may be an evolutionary remnant inherited from ancestors wherein these organs were copatterned from common epithelium.
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Affiliation(s)
- Ryan F Bloomquist
- School of Biology and Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332; College of Dental Medicine, Georgia Regents University, Augusta, GA 30912;
| | - Nicholas F Parnell
- School of Biology and Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332
| | - Kristine A Phillips
- School of Biology and Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332
| | - Teresa E Fowler
- School of Biology and Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332
| | - Tian Y Yu
- Department of Craniofacial Development and Stem Cell Biology, Dental Institute, King's College London, London WC2R 2LS, United Kingdom
| | - Paul T Sharpe
- Department of Craniofacial Development and Stem Cell Biology, Dental Institute, King's College London, London WC2R 2LS, United Kingdom
| | - J Todd Streelman
- School of Biology and Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332;
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16
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Pardo-Diaz C, Salazar C, Jiggins CD. Towards the identification of the loci of adaptive evolution. Methods Ecol Evol 2015; 6:445-464. [PMID: 25937885 PMCID: PMC4409029 DOI: 10.1111/2041-210x.12324] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Accepted: 11/28/2014] [Indexed: 12/17/2022]
Abstract
1. Establishing the genetic and molecular basis underlying adaptive traits is one of the major goals of evolutionary geneticists in order to understand the connection between genotype and phenotype and elucidate the mechanisms of evolutionary change. Despite considerable effort to address this question, there remain relatively few systems in which the genes shaping adaptations have been identified. 2. Here, we review the experimental tools that have been applied to document the molecular basis underlying evolution in several natural systems, in order to highlight their benefits, limitations and suitability. In most cases, a combination of DNA, RNA and functional methodologies with field experiments will be needed to uncover the genes and mechanisms shaping adaptation in nature.
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Affiliation(s)
- Carolina Pardo-Diaz
- Biology Program, Faculty of Natural Sciences and Mathematics, Universidad del RosarioCarrera 24 No 63C-69, Bogotá 111221, Colombia
| | - Camilo Salazar
- Biology Program, Faculty of Natural Sciences and Mathematics, Universidad del RosarioCarrera 24 No 63C-69, Bogotá 111221, Colombia
| | - Chris D Jiggins
- Department of Zoology, University of CambridgeDowning Street, Cambridge, CB2 3EJ, UK
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17
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Ding B, Daugherty DW, Husemann M, Chen M, Howe AE, Danley PD. Quantitative Genetic Analyses of Male Color Pattern and Female Mate Choice in a Pair of Cichlid Fishes of Lake Malawi, East Africa. PLoS One 2014; 9:e114798. [PMID: 25494046 PMCID: PMC4262453 DOI: 10.1371/journal.pone.0114798] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Accepted: 10/29/2014] [Indexed: 12/28/2022] Open
Abstract
The traits involved in sexual selection, such as male secondary sexual characteristics and female mate choice, often co-evolve which can promote population differentiation. However, the genetic architecture of these phenotypes can influence their evolvability and thereby affect the divergence of species. The extraordinary diversity of East African cichlid fishes is often attributed to strong sexual selection and thus this system provides an excellent model to test predictions regarding the genetic architecture of sexually selected traits that contribute to reproductive isolation. In particular, theory predicts that rapid speciation is facilitated when male sexual traits and female mating preferences are controlled by a limited number of linked genes. However, few studies have examined the genetic basis of male secondary sexual traits and female mating preferences in cichlids and none have investigated the genetic architecture of both jointly. In this study, we artificially hybridized a pair of behaviorally isolated cichlid fishes from Lake Malawi and quantified both melanistic color pattern and female mate choice. We investigated the genetic architecture of both phenotypes using quantitative genetic analyses. Our results suggest that 1) many non-additively acting genetic factors influence melanistic color patterns, 2) female mate choice may be controlled by a minimum of 1-2 non-additive genetic factors, and 3) F2 female mate choice is not influenced by male courting effort. Furthermore, a joint analysis of color pattern and female mate choice indicates that the genes underlying these two traits are unlikely to be physically linked. These results suggest that reproductive isolation may evolve rapidly owing to the few genetic factors underlying female mate choice. Hence, female mate choice likely played an important role in the unparalleled speciation of East African cichlid fish.
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Affiliation(s)
- Baoqing Ding
- Biology Department, Baylor University, One Bear Place #97388, Waco, Texas, 76798, United States of America
| | - Daniel W. Daugherty
- Biology Department, Baylor University, One Bear Place #97388, Waco, Texas, 76798, United States of America
| | - Martin Husemann
- Biology Department, Baylor University, One Bear Place #97388, Waco, Texas, 76798, United States of America
| | - Ming Chen
- Biology Department, Baylor University, One Bear Place #97388, Waco, Texas, 76798, United States of America
| | - Aimee E. Howe
- Biology Department, Baylor University, One Bear Place #97388, Waco, Texas, 76798, United States of America
| | - Patrick D. Danley
- Biology Department, Baylor University, One Bear Place #97388, Waco, Texas, 76798, United States of America
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18
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Wellenreuther M, Svensson EI, Hansson B. Sexual selection and genetic colour polymorphisms in animals. Mol Ecol 2014; 23:5398-414. [DOI: 10.1111/mec.12935] [Citation(s) in RCA: 115] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2014] [Revised: 09/17/2014] [Accepted: 09/19/2014] [Indexed: 12/01/2022]
Affiliation(s)
- Maren Wellenreuther
- Evolutionary Ecology; Department of Biology; Lund University; SE-223 62 Lund Sweden
| | - Erik I. Svensson
- Evolutionary Ecology; Department of Biology; Lund University; SE-223 62 Lund Sweden
| | - Bengt Hansson
- Molecular Ecology; Department of Biology; Lund University; SE-223 62 Lund Sweden
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19
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Henning F, Lee HJ, Franchini P, Meyer A. Genetic mapping of horizontal stripes in Lake Victoria cichlid fishes: benefits and pitfalls of using RAD markers for dense linkage mapping. Mol Ecol 2014; 23:5224-40. [PMID: 25039588 DOI: 10.1111/mec.12860] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Revised: 07/02/2014] [Accepted: 07/12/2014] [Indexed: 01/25/2023]
Abstract
The genetic dissection of naturally occurring phenotypes sheds light on many fundamental and longstanding questions in speciation and adaptation and is a central research topic in evolutionary biology. Until recently, forward-genetic approaches were virtually impossible to apply to nonmodel organisms, but the development of next-generation sequencing techniques eases this difficulty. Here, we use the ddRAD-seq method to map a colour trait with a known adaptive function in cichlid fishes, well-known textbook examples for rapid rates of speciation and astonishing phenotypic diversification. A suite of phenotypic key innovations is related to speciation and adaptation in cichlids, among which body coloration features prominently. The focal trait of this study, horizontal stripes, evolved in parallel in several cichlid radiations and is associated with piscivorous foraging behaviour. We conducted interspecific crosses between Haplochromis sauvagei and H. nyererei and constructed a linkage map with 867 SNP markers distributed on 22 linkage groups and total size of 1130.63 cM. Lateral stripes are inherited as a Mendelian trait and map to a single genomic interval that harbours a paralog of a gene with known function in stripe patterning. Dorsolateral and mid-lateral stripes were always coinherited and are thus under the same genetic control. Additionally, we directly quantify the genotyping error rates in RAD markers and offer guidelines for identifying and dealing with errors. Uncritical marker selection was found to severely impact linkage map construction. Fortunately, by applying appropriate quality control steps, a genotyping accuracy of >99.9% can be reached, thus allowing for efficient linkage mapping of evolutionarily relevant traits.
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Affiliation(s)
- Frederico Henning
- Lehrstuhl für Zoologie und Evolutionsbiologie, Department of Biology, University of Konstanz, Universitätsstraße 10, Konstanz, 78457, Germany
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20
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Henning F, Meyer A. The evolutionary genomics of cichlid fishes: explosive speciation and adaptation in the postgenomic era. Annu Rev Genomics Hum Genet 2014; 15:417-41. [PMID: 24898042 DOI: 10.1146/annurev-genom-090413-025412] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
With more than 1,500 species, cichlid fishes provide textbook examples of recent and diverse adaptive radiations, rapid rates of speciation, and the parallel evolution of adaptive phenotypes among both recently and distantly related lineages. This extraordinary diversity has attracted considerable interest from researchers across several biological disciplines. Their broad phenotypic variation coupled with recent divergence makes cichlids an ideal model system for understanding speciation, adaptation, and phenotypic diversification. Genetic mapping, genome-wide analyses, and genome projects have flourished in the past decade and have added new insights on the question of why there are so many cichlids. These recent findings also show that the sharing of older DNA polymorphisms is extensive and suggest that linage sorting is incomplete and that adaptive introgression played a role in the African radiation. Here, we review the results of genetic and genomic research on cichlids in the past decade and suggest some potential avenues to further exploit the potential of the cichlid model system to provide a better understanding of the genomics of adaptation and speciation.
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Affiliation(s)
- Frederico Henning
- Department of Biology, University of Konstanz, 78457 Konstanz, Germany;
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21
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Fuji K, Koyama T, Kai W, Kubota S, Yoshida K, Ozaki A, Aoki JY, Kawabata Y, Araki K, Tsuzaki T, Okamoto N, Sakamoto T. Construction of a high-coverage bacterial artificial chromosome library and comprehensive genetic linkage map of yellowtail Seriola quinqueradiata. BMC Res Notes 2014; 7:200. [PMID: 24684753 PMCID: PMC4230249 DOI: 10.1186/1756-0500-7-200] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Accepted: 02/26/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Japanese amberjack/yellowtail (Seriola quinqueradiata) is a commonly cultured marine fish in Japan. For cost effective fish production, a breeding program that increases commercially important traits is one of the major solutions. In selective breeding, information of genetic markers is useful and sufficient to identify individuals carrying advantageous traits but if the aim is to determine the genetic basis of the trait, large insert genomic DNA libraries are essential. In this study, toward prospective understanding of genetic basis of several economically important traits, we constructed a high-coverage bacterial artificial chromosome (BAC) library, obtained sequences from the BAC-end, and constructed comprehensive female and male linkage maps of yellowtail using Simple Sequence Repeat (SSR) markers developed from the BAC-end sequences and a yellowtail genomic library. RESULTS The total insert length of the BAC library we constructed here was estimated to be approximately 11 Gb and hence 16-times larger than the yellowtail genome. Sequencing of the BAC-ends showed a low fraction of repetitive sequences comparable to that in Tetraodon and fugu. A total of 837 SSR markers developed here were distributed among 24 linkage groups spanning 1,026.70 and 1,057.83 cM with an average interval of 4.96 and 4.32 cM in female and male map respectively without any segregation distortion. Oxford grids suggested conserved synteny between yellowtail and stickleback. CONCLUSIONS In addition to characteristics of yellowtail genome such as low repetitive sequences and conserved synteny with stickleback, our genomic and genetic resources constructed and revealed here will be powerful tools for the yellowtail breeding program and also for studies regarding the genetic basis of traits.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | - Takashi Sakamoto
- Faculty of Marine Science, Tokyo University of Marine Science and Technology, 4-5-7, Konan, Minato-ku, Tokyo 108-8477, Japan.
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22
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Miyagi R, Terai Y. The diversity of male nuptial coloration leads to species diversity in Lake Victoria cichlids. Genes Genet Syst 2014; 88:145-53. [PMID: 24025243 DOI: 10.1266/ggs.88.145] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The amazing coloration shown by diverse cichlid fish not only fascinates aquarium keepers, but also receives great attention from biologists interested in speciation because of its recently-revealed role in their adaptive radiation in an African lake. We review the important role of coloration in the speciation and adaptive evolution of Lake Victoria cichlids, which have experienced adaptive radiation during a very short evolutionary period. Mature male cichlids display their colors during mate choice. The color of their skin reflects light, and the reflected light forms a color signal that is received by the visual system of females. The adaptive divergence of visual perceptions shapes and diverges colorations, to match the adapted visual perceptions. The divergence of visual perception and coloration indicates that the divergence of color signals causes reproductive isolation between species, and this process leads to speciation. Differences in color signals among coexisting species act to maintain reproductive isolation by preventing hybridization. Thus, the diversity of coloration has caused speciation and has maintained species diversity in Lake Victoria cichlids.
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Affiliation(s)
- Ryutaro Miyagi
- Department of Biological Sciences, Tokyo Metropolitan University
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23
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Kuroiwa A, Terai Y, Kobayashi N, Yoshida K, Suzuki M, Nakanishi A, Matsuda Y, Watanabe M, Okada N. Construction of chromosome markers from the Lake Victoria cichlid Paralabidochromis chilotes and their application to comparative mapping. Cytogenet Genome Res 2013; 142:112-20. [PMID: 24217467 DOI: 10.1159/000356128] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/11/2013] [Indexed: 11/19/2022] Open
Abstract
Cichlid fishes in the African Great Lakes are known as a spectacular example of adaptive radiation in vertebrates. Four linkage maps have been constructed to identify the genes responsible for adaptation and speciation, and the genetic linkages of those genes are assumed to play an important role during adaptive evolution. However, it is difficult to analyze such linkages because the linkage groups of one species do not match well with those of the other species. Chromosome markers are a powerful tool for the direct identification of linkage homology between different species. We used information about the linkage map of the Lake Malawi cichlid (Labeotropheus fuelleborni/Metriaclima zebra) to isolate bacterial artificial chromosome (BAC) clones from the BAC library of Paralabidochromis chilotes, Lake Victoria. We identified 18 of 22 P. chilotes chromosomes by single- and multi-color BAC fluorescence in situ hybridization using 19 BAC clones. Comparative mapping with the chromosome markers of P. chilotes in Astatotilapia burtoni (2n = 40) from Lake Tanganyika revealed the chromosome rearrangements that have occurred in this lineage. These chromosome markers will be useful for delineating the process of genome and chromosome evolution in African species.
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Affiliation(s)
- A Kuroiwa
- Laboratory of Animal Cytogenetics, Faculty of Science, Hokkaido University, Sapporo, Japan
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24
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Bernardi G. Speciation in fishes. Mol Ecol 2013; 22:5487-502. [PMID: 24118417 DOI: 10.1111/mec.12494] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Revised: 08/08/2013] [Accepted: 08/14/2013] [Indexed: 12/27/2022]
Abstract
The field of speciation has seen much renewed interest in the past few years, with theoretical and empirical advances that have moved it from a descriptive field to a predictive and testable one. The goal of this review is to provide a general background on research on speciation as it pertains to fishes. Three major components to the question are first discussed: the spatial, ecological and sexual factors that influence speciation mechanisms. We then move to the latest developments in the field of speciation genomics. Affordable and rapidly available, massively parallel sequencing data allow speciation studies to converge into a single comprehensive line of investigation, where the focus has shifted to the search for speciation genes and genomic islands of speciation. We argue that fish present a very diverse array of scenarios, making them an ideal model to study speciation processes.
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Affiliation(s)
- Giacomo Bernardi
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, 100 Shaffer Road, Santa Cruz, CA, 95076, USA
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25
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Maan ME, Sefc KM. Colour variation in cichlid fish: developmental mechanisms, selective pressures and evolutionary consequences. Semin Cell Dev Biol 2013; 24:516-28. [PMID: 23665150 PMCID: PMC3778878 DOI: 10.1016/j.semcdb.2013.05.003] [Citation(s) in RCA: 112] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Revised: 04/15/2013] [Accepted: 05/01/2013] [Indexed: 12/17/2022]
Abstract
Cichlid fishes constitute one of the most species-rich families of vertebrates. In addition to complex social behaviour and morphological versatility, they are characterised by extensive diversity in colouration, both within and between species. Here, we review the cellular and molecular mechanisms underlying colour variation in this group and the selective pressures responsible for the observed variation. We specifically address the evidence for the hypothesis that divergence in colouration is associated with the evolution of reproductive isolation between lineages. While we conclude that cichlid colours are excellent models for understanding the role of animal communication in species divergence, we also identify taxonomic and methodological biases in the current research effort. We suggest that the integration of genomic approaches with ecological and behavioural studies, across the entire cichlid family and beyond it, will contribute to the utility of the cichlid model system for understanding the evolution of biological diversity.
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Affiliation(s)
- Martine E. Maan
- University of Groningen, Behavioural Biology, PO Box 11103, 9700 CC Groningen, The Netherlands
| | - Kristina M. Sefc
- Institute of Zoology, University of Graz, Universitätsplatz 2, A-8010 Graz, Austria
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26
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Genetic interactions controlling sex and color establish the potential for sexual conflict in Lake Malawi cichlid fishes. Heredity (Edinb) 2012; 110:239-46. [PMID: 23092997 DOI: 10.1038/hdy.2012.73] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Sex-determining systems may evolve rapidly and contribute to lineage diversification. In fact, recent work has suggested an integral role of sex chromosome evolution in models of speciation. We use quantitative trait loci analysis of restriction site-associated DNA -tag single nucleotide polymorphisms to identify multiple loci responsible for sex determination and reproductively adaptive color phenotypes in Lake Malawi cichlids. We detect a complex epistatic sex system consisting of a major female heterogametic ZW locus on chromosome 5, two separate male heterogametic XY loci on chromosome 7, and two additional interacting loci on chromosomes 3 and 20. Our data support the known chromosomal linkage between orange blotch color and ZW, as well as novel genetic associations between male blue nuptial color and two sex determining regions (an XY and ZW locus). These results provide further empirical evidence for a complex antagonistic sex-color system in this species flock and suggest a possible role for, and effect of, polygenic sex-determining systems in rapid evolutionary diversification.
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27
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Kronforst MR, Barsh GS, Kopp A, Mallet J, Monteiro A, Mullen SP, Protas M, Rosenblum EB, Schneider CJ, Hoekstra HE. Unraveling the thread of nature's tapestry: the genetics of diversity and convergence in animal pigmentation. Pigment Cell Melanoma Res 2012; 25:411-33. [PMID: 22578174 DOI: 10.1111/j.1755-148x.2012.01014.x] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Animals display incredibly diverse color patterns yet little is known about the underlying genetic basis of these phenotypes. However, emerging results are reshaping our view of how the process of phenotypic evolution occurs. Here, we outline recent research from three particularly active areas of investigation: melanin pigmentation in Drosophila, wing patterning in butterflies, and pigment variation in lizards. For each system, we highlight (i) the function and evolution of color variation, (ii) various approaches that have been used to explore the genetic basis of pigment variation, and (iii) conclusions regarding the genetic basis of convergent evolution which have emerged from comparative analyses. Results from these studies indicate that natural variation in pigmentation is a particularly powerful tool to examine the molecular basis of evolution, especially with regard to convergent or parallel evolution. Comparison of these systems also reveals that the molecular basis of convergent evolution is heterogeneous, sometimes involving conserved mechanisms and sometimes not. In the near future, additional work in other emerging systems will substantially expand the scope of available comparisons.
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28
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Horth L, Panayotova IN. Simulating the maintenance of a rare fish morph experiencing negative frequency dependent selection. Biosystems 2012; 110:149-55. [PMID: 23025992 DOI: 10.1016/j.biosystems.2012.08.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2011] [Revised: 08/14/2012] [Accepted: 08/25/2012] [Indexed: 10/27/2022]
Abstract
Empirical work assessing the maintenance of rare genotypes in natural populations is difficult over very long time scales. Skirting this problematic issue is possible with theory and simulations. Major theoretical constructs, including mutation-selection balance and balancing selection, explain the theoretical maintenance of rare genotypes, and the occurrence of multiple, rare genotypes over time. Additionally, numerical simulations are valuable tools for assessing evolving biological systems because they allow for monitoring systems over long time scales, as well as for controlling model parameters, thus contributing to the exploration of system dynamics that cannot be assessed in nature. Here we employed numerical simulations to explore the importance of several biological factors that contribute to the maintenance of a fish color-pattern polymorphism. We present a numerical model of a two-morph fish polymorphism that allowed us to test the sensitivity of the rare morph's persistence and the population's stability to multiple parameters. Our simulations ran over 10,000 years (where one year is approximately one generation) and demonstrated the maintenance of a stable polymorphism with a rare morph which persisted at a frequency of ~10(-2), which is in-fact the frequency of the rare, mottled black mosquitofish morph in natural populations. This pigmentation polymorphism is stable, independent of changes in population size, but can be destabilized with very high predation when coupled with very low birth rates. Employing models with empirical fitness estimates is a valuable tool for monitoring rare vertebrate morphs in nature, however few studies exist that have accomplished this task. Our approach can be adapted for modeling rare morphs (particularly in additional live-bearing fishes like sailfin mollies) that also harbor rare, pigmentation morphs within large populations.
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Affiliation(s)
- Lisa Horth
- Department of Biology, 4700 Elkhorn Ave Old Dominion University, Norfolk, VA 23529, USA.
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29
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Abstract
The relationship between form and function can have profound effects on evolutionary dynamics and such effects may differ for simple versus complex systems. In particular, functions produced by multiple structural configurations (many-to-one mapping, MTOM) may dampen constituent trade-offs and promote diversification. Unfortunately, we lack information about the genetic architecture of MTOM functional systems. The skulls of teleost fishes contain both simple (lower jaw levers) as well as more complex (jaws modeled as 4-bar linkages) functional systems within the same craniofacial unit. We examined the mapping of form to function and the genetic basis of these systems by identifying quantitative trait loci (QTL) in hybrids of two Lake Malawi cichlid species. Hybrid individuals exhibited novelty (transgressive segregation) in morphological components and function of the simple and complex jaw systems. Functional novelty was proportional to the prevalence of extreme morphologies in the simple levers; by contrast, recombination of parental morphologies produced transgression in the MTOM 4-bar linkage. We found multiple loci of moderate effect and epistasis controlling jaw phenotypes in both the simple and complex systems, with less phenotypic variance explained by QTL for the 4-bar. Genetic linkage between components of the simple and complex systems partly explains phenotypic correlations and may constrain functional evolution.
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Affiliation(s)
- Nicholas F Parnell
- School of Biology, Institute of Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.
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30
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Genetic and Morphological Evidence Implies Existence of Two Sympatric Species in Cyathopharynx furcifer (Teleostei: Cichlidae) from Lake Tanganyika. INTERNATIONAL JOURNAL OF EVOLUTIONARY BIOLOGY 2012; 2012:980879. [PMID: 22675655 PMCID: PMC3363988 DOI: 10.1155/2012/980879] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/03/2012] [Accepted: 03/10/2012] [Indexed: 11/17/2022]
Abstract
Although the cichlid fishes from Lake Tanganyika are treated as a textbook example of adaptive radiation, many taxonomic problems remain unresolved. Cyathopharynx furcifer, which belongs to the currently monospecific genus Cyathopharynx, contains two colour morphs at the southern end of the lake: one has a yellow anal fin, and the other has a black anal fin. Some books for hobbyists of ornamental fish treat these morphs as different species, but taxonomic studies have neither mentioned the existence nor addressed the status of these colour morphs. In the present paper, we analysed these two colour morphs using mitochondrial, microsatellite, morphometric, and meristic data sets. Both molecular and morphological data allowed clear discrimination between these morphs, suggesting the existence of two distinct sympatric species. Three taxonomic species have been described in this genus, and only C. furcifer is currently considered valid. Observations of type specimens of these three nominal species will be needed to determine the scientific names of these colour morphs.
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31
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Gilman RT, Behm JE. HYBRIDIZATION, SPECIES COLLAPSE, AND SPECIES REEMERGENCE AFTER DISTURBANCE TO PREMATING MECHANISMS OF REPRODUCTIVE ISOLATION. Evolution 2011; 65:2592-605. [DOI: 10.1111/j.1558-5646.2011.01320.x] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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32
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Gunter HM, Clabaut C, Salzburger W, Meyer A. Identification and characterization of gene expression involved in the coloration of cichlid fish using microarray and qRT-PCR approaches. J Mol Evol 2011; 72:127-37. [PMID: 21267555 DOI: 10.1007/s00239-011-9431-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2010] [Accepted: 01/03/2011] [Indexed: 01/09/2023]
Abstract
It has been suggested that speciation on the basis of sexual selection is an important mechanism for the generation of new species for East African cichlids, where male body coloration is one of the major discriminatory factors used by females in mate choice. To gain insight into the molecular basis of cichlid coloration, we studied the Lake Malawi cichlid Pseudotropheus saulosi, comparing transcription in the bright blue skin of males to the yellow skin of females. Our cDNA microarray experiments identified 46 clones that exhibited expression differences between the two sexes, of which five were confirmed to be differentially expressed by relative quantitative real-time PCR (qRT-PCR). This gene list includes a representative from the endosomal-to-Golgi vesicle trafficking pathway, Coatomer protein complex, subunit zeta-1 (Copz-1), which is known to be a critical determinant of pigmentation in humans and zebrafish. With the support of microscopic images of the skin of these specimens, we interpret the transcriptional differences between the blue males and yellow females. Here, we provide insight into the putative functional diversification of genes involved in the coloration of cichlids and by extension, on the evolution of coloration in teleost fish.
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Affiliation(s)
- Helen M Gunter
- Lehrstuhl für Zoologie und Evolutionsbiologie, Department of Biology, University of Konstanz, Universitätsstr 10, 78457 Constance, Germany
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33
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Abstract
MicroRNAs (miRNAs) are ancient, short noncoding RNA molecules that regulate the transcriptome through post-transcriptional mechanisms. miRNA riboregulation is involved in a diverse range of biological processes, and misregulation is implicated in disease. It is generally thought that miRNAs function to canalize cellular outputs, for instance as “fail-safe” repressors of gene misexpression. Genomic surveys in humans have revealed reduced genetic polymorphism and the signature of negative selection for both miRNAs themselves and the target sequences to which they are predicted to bind. We investigated the evolution of miRNAs and their binding sites across cichlid fishes from Lake Malawi (East Africa), where hundreds of diverse species have evolved in the last million years. Using low-coverage genome sequence data, we identified 100 cichlid miRNA genes with mature regions that are highly conserved in other animal species. We computationally predicted target sites on the 3′-untranslated regions (3′-UTRs) of cichlid genes to which miRNAs may bind and found that these sites possessed elevated single nucleotide polymorphism (SNP) densities. Furthermore, polymorphic sites in predicted miRNA targets showed higher minor allele frequencies on average and greater genetic differentiation between Malawi lineages when compared with a neutral expectation and nontarget 3′-UTR SNPs. Our data suggest that divergent selection on miRNA riboregulation may have contributed to the diversification of cichlid species and may similarly play a role in rapid phenotypic evolution of other natural systems.
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Affiliation(s)
- Yong-Hwee E Loh
- School of Biology, Georgia Institute of Technology, Georgia, USA
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34
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Dalton BE, Cronin TW, Marshall NJ, Carleton KL. The fish eye view: are cichlids conspicuous? ACTA ACUST UNITED AC 2010; 213:2243-55. [PMID: 20543123 DOI: 10.1242/jeb.037671] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The extent of animal colouration is determined by an interplay between natural and sexual selection. Both forces probably shape colouration in the speciose, rock-dwelling cichlids of Lake Malawi. Sexual selection is thought to drive male colouration, overcoming natural selection to create conspicuous colour patterns via female mate choice and male-male competition. However, natural selection should make female cichlids cryptic because they mouthbrood their young. We hypothesize that as a result of both sexual and natural selection, males will have colours that are more conspicuous than female colours. Cichlid spectral sensitivity, especially in the ultraviolet, probably influences how colours appear to them. Here we use simple models of the trichromatic colour space of cichlid visual systems to compare the conspicuousness of male and female nuptial colours of nine species. Conspicuousness of colours was evaluated as their Euclidian distance in colour space from environmental backgrounds and from other colours on the same fish. We find in six of the nine species that breeding males have colours that are statistically more conspicuous than female colours. These colours contrast strongly with each other or with the backgrounds, and they fall within a range of spectra best transmitted in the habitat. Female colour distances were sometimes smaller, suggesting that females of some species are more cryptic than males. Therefore, selection can differentially act to generate male colours that are more conspicuous than those in females. However, in two species, females had colours that were more conspicuous than male colours, suggesting that other selective forces and possibly sexual conflicts are acting in this system.
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Affiliation(s)
- Brian E Dalton
- Department of Biology, University of Maryland, Baltimore County, MD 21250, USA
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MAGALHAES IS, MWAIKO S, SEEHAUSEN O. Sympatric colour polymorphisms associated with nonrandom gene flow in cichlid fish of Lake Victoria. Mol Ecol 2010; 19:3285-300. [DOI: 10.1111/j.1365-294x.2010.04751.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Abstract
Many animal taxa show frequent and rapid transitions between male heterogamety (XY) and female heterogamety (ZW). We develop a model showing how these transitions can be driven by sex-antagonistic selection. Sex-antagonistic selection acting on loci linked to a new sex-determination mutation can cause it to invade, but when acting on loci linked to the ancestral sex-determination gene will inhibit an invasion. The strengths of the consequent indirect selection on the old and new sex-determination loci are mediated by the strengths of sex-antagonistic selection, linkage between the sex-antagonistic and sex-determination genes, and the amount of genetic variation. Sex-antagonistic loci that are tightly linked to a sex-determining gene have a vastly stronger influence on the balance of selection than more distant loci. As a result, changes in linkage, caused, for example, by an inversion that captures a sex-determination mutation and a gene under sex-antagonistic selection, can trigger transitions between XY and ZW systems. Sex-antagonistic alleles can become more strongly associated with pleiotropically dominant sex-determining factors, which may help to explain biases in the rates of transitions between male and female heterogamety. Deleterious recessive mutations completely linked to the ancestral Y chromosome can prevent invasion of a neo-W chromosome or result in a stable equilibrium at which XY and ZW systems segregate simultaneously at two linkage groups.
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Carleton KL, Hofmann CM, Klisz C, Patel Z, Chircus LM, Simenauer LH, Soodoo N, Albertson RC, Ser JR. Genetic basis of differential opsin gene expression in cichlid fishes. J Evol Biol 2010; 23:840-53. [PMID: 20210829 PMCID: PMC2996586 DOI: 10.1111/j.1420-9101.2010.01954.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Visual sensitivity can be tuned by differential expression of opsin genes. Among African cichlid fishes, seven cone opsin genes are expressed in different combinations to produce diverse visual sensitivities. To determine the genetic architecture controlling these adaptive differences, we analysed genetic crosses between species expressing different complements of opsin genes. Quantitative genetic analyses suggest that expression is controlled by only a few loci with correlations among some genes. Genetic mapping identifies clear evidence of trans-acting factors in two chromosomal regions that contribute to differences in opsin expression as well as one cis-regulatory region. Therefore, both cis and trans regulation are important. The simple genetic architecture suggested by these results may explain why opsin gene expression is evolutionarily labile, and why similar patterns of expression have evolved repeatedly in different lineages.
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Affiliation(s)
- K L Carleton
- Department of Biology, University of Maryland, College Park, MD, USA
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Stewart TA, Albertson RC. Evolution of a unique predatory feeding apparatus: functional anatomy, development and a genetic locus for jaw laterality in Lake Tanganyika scale-eating cichlids. BMC Biol 2010; 8:8. [PMID: 20102595 PMCID: PMC2828976 DOI: 10.1186/1741-7007-8-8] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2009] [Accepted: 01/26/2010] [Indexed: 11/14/2022] Open
Abstract
Background While bilaterality is a defining characteristic of triploblastic animals, several assemblages have managed to break this symmetry in order to exploit the adaptive peaks garnered through the lateralization of behaviour or morphology. One striking example of an evolved asymmetry in vertebrates comes from a group of scale-eating cichlid fishes from Lake Tanganyika. Members of the Perissodini tribe of cichlid fishes have evolved dental and craniofacial asymmetries in order to more effectively remove scales from the left or right flanks of prey. Here we examine the evolution and development of craniofacial morphology and laterality among Lake Tanganyika scale-eating cichlids. Results Using both geometric and traditional morphometric methods we found that the craniofacial evolution in the Perissodini involved discrete shifts in skeletal anatomy that reflect differences in habitat preference and predation strategies. Further, we show that the evolutionary history of the Perissodini is characterized by an accentuation of craniofacial laterality such that certain taxa show elaborate sided differences in craniofacial shape consistent with the sub-partitioning of function between sides of the head during attacks. Craniofacial laterality in the scale-eating specialist Perissodus microlepis was found to be evident early in development and exhibited a unimodal distribution, which is contrary to the adult condition where jaw laterality has been described as a discrete, bimodal antisymmetry. Finally, using linkage and association analyses we identified a conserved locus for jaw handedness that segregates among East African cichlids. Conclusions We suggest that, during the evolution of the Perissodini, selection has accentuated a latent, genetically determined handedness of the craniofacial skeleton, enabling the evolution of jaw asymmetries in order to increase predation success. Continued work on the developmental genetic basis of laterality in the Perissodini will facilitate a better understanding of the evolution of this unique group of fishes, as well as of left-right axis determination among vertebrates in general.
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Affiliation(s)
- Thomas A Stewart
- Department of Biology, Syracuse University, 130 College Place, Syracuse, NY 13244, USA
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Ser JR, Roberts RB, Kocher TD. Multiple interacting loci control sex determination in lake Malawi cichlid fish. Evolution 2009; 64:486-501. [PMID: 19863587 DOI: 10.1111/j.1558-5646.2009.00871.x] [Citation(s) in RCA: 131] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Several models have been proposed to suggest how the evolution of sex-determining mechanisms might contribute to speciation. Here, we describe the inheritance of sex in 19 fish species from the rapidly evolving flock of cichlids in Lake Malawi, Africa. We found that many of these species have a male heterogametic (XY) system on linkage group 7. Some species also segregate for a female heterogametic (ZW) system on linkage group 5 that is coincident with a dominant orange-blotch (OB) color pattern in females. The ZW system is epistatically dominant to the XY system when both are segregating within a family. Several lines of evidence suggest that additional sex-determining loci are segregating in some species. These results are consistent with the idea that genetic conflicts play an important role in the evolution of these species flocks and suggest that evolution of sex-determining mechanisms has contributed to the radiation of cichlid fish in East Africa.
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Affiliation(s)
- Jennifer R Ser
- Department of Biology, University of Maryland, College Park, Maryland 20742, USA
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Abstract
Absolute barriers to dispersal are not common in marine systems, and the prevalence of planktonic larvae in marine taxa provides potential for gene flow across large geographic distances. These observations raise the fundamental question in marine evolutionary biology as to whether geographic and oceanographic barriers alone can account for the high levels of species diversity observed in marine environments such as coral reefs, or whether marine speciation also operates in the presence of gene flow between diverging populations. In this respect, the ecological hypothesis of speciation, in which reproductive isolation results from divergent or disruptive natural selection, is of particular interest because it may operate in the presence of gene flow. Although important insights into the process of ecological speciation in aquatic environments have been provided by the study of freshwater fishes, comparatively little is known about the possibility of ecological speciation in marine teleosts. In this study, the evidence consistent with different aspects of the ecological hypothesis of speciation is evaluated in marine fishes. Molecular approaches have played a critical role in the development of speciation hypotheses in marine fishes, with a role of ecology suggested by the occurrence of sister clades separated by ecological factors, rapid cladogenesis or the persistence of genetically and ecologically differentiated species in the presence of gene flow. Yet, ecological speciation research in marine fishes is still largely at an exploratory stage. Cases where the major ingredients of ecological speciation, namely a source of natural divergent or disruptive selection, a mechanism of reproductive isolation and a link between the two have been explicitly documented are few. Even in these cases, specific predictions of the ecological hypothesis of speciation remain largely untested. Recent developments in the study of freshwater fishes illustrate the potential for molecular approaches to address specific questions related to the ecological hypothesis of speciation such as the nature of the genes underlying key ecological traits, the magnitude of their effect on phenotype and the mechanisms underlying their differential expression in different ecological contexts. The potential provided by molecular studies is fully realized when they are complemented with alternative (e.g. ecological, theoretical) approaches.
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Affiliation(s)
- O Puebla
- Smithsonian Tropical Research Institute, Apartado Postal 0843-03092, Balboa, Ancon, Republic of Panama.
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Roberts RB, Ser JR, Kocher TD. Sexual conflict resolved by invasion of a novel sex determiner in Lake Malawi cichlid fishes. Science 2009; 326:998-1001. [PMID: 19797625 DOI: 10.1126/science.1174705] [Citation(s) in RCA: 245] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Sex determination mechanisms differ among animal species, but it is not clear how these differences evolve. New sex determiners may arise in response to sexual conflicts, which occur when traits benefit one sex but hinder the other. We identified the genetic basis for the orange-blotch (OB) color pattern, a trait under sexually antagonistic selection in the cichlid fish of Lake Malawi, East Africa. The OB phenotype is due to a cis-regulatory mutation in the Pax7 gene. OB provides benefits of camouflage to females but disrupts the species-specific male color patterns used for mate recognition. We suggest that the resulting sexual conflict over the OB allele has been resolved by selection for a novel female sex determination locus that has invaded populations with an ancestral male sex determination system.
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Affiliation(s)
- Reade B Roberts
- Department of Biology, University of Maryland, College Park, MD 20742, USA
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42
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Hulsey CD. Cichlid genomics and phenotypic diversity in a comparative context. Integr Comp Biol 2009; 49:618-29. [DOI: 10.1093/icb/icp071] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Abstract
Intralocus sexual conflict arises when there are sex-specific optima for a trait that is expressed in both sexes and when the constraint of a shared gene pool prevents males and females from reaching their optima independently. This situation may result in a negative intersexual correlation for fitness. Here I first discuss key differences between intra- and interlocus conflict, the type of sexual conflict that arises in mating interactions between males and females. I then review the experimental evidence for the existence of genomewide sexually antagonistic variation and discuss how intralocus conflict can be resolved. Substantial genomewide sexually antagonistic variation exists in Drosophila melanogaster lab populations. Yet, in the same species, sex-specific gene regulation appears to evolve rapidly, suggesting that the obstacles to the resolution of intralocus conflict are minor. The fact that negative intersexual correlations for fitness are observed even if sexual dimorphism can evolve rapidly suggests that intralocus conflict is highly dynamic. The final part of this review examines the evolutionary consequences of intralocus sexual conflict for the evolution of the sex chromosomes, sexual selection, and sex determination. Intralocus conflict helps to explain many of the peculiar features of the sex chromosomes and has shaped the functional bias and expression biases of sex-linked genes. The genomic distribution of sexually selected genes, in particular, affects sexual selection in various ways. The presence of sexually antagonistic variation can strongly interfere with the good genes' process of sexual selection and erode the genetic benefits of mate choice. Regarding sex determination, this review concentrates on evolutionary transitions between different sex determination mechanisms. Such transitions have occurred frequently in several taxa. Theory and empirical data suggest an important role for intralocus conflict in triggering switches between sex determination systems.
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SALZBURGER WALTER. The interaction of sexually and naturally selected traits in the adaptive radiations of cichlid fishes. Mol Ecol 2009; 18:169-85. [DOI: 10.1111/j.1365-294x.2008.03981.x] [Citation(s) in RCA: 193] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Abstract
There is an amazing amount of diversity in coloration patterns in nature. The ease of observing this diversity and the recent application of genetic and molecular techniques to model and nonmodel animals are allowing us to investigate the genetic basis and evolution of coloration in an ever-increasing variety of animals. It is now possible to ask questions about how many genes are responsible for any given pattern, what types of genetic changes have occurred to generate the diversity, and if the same underlying genetic changes occur repeatedly when coloration phenotypes arise through convergent evolution or parallel evolution.
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Affiliation(s)
- Meredith E Protas
- Department of Integrative Biology, University of California, Berkeley, California 94720-3140, USA
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A microsatellite-based genetic linkage map of the cichlid fish, Astatotilapia burtoni (Teleostei): a comparison of genomic architectures among rapidly speciating cichlids. Genetics 2008; 182:387-97. [PMID: 18757932 DOI: 10.1534/genetics.108.089367] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Cichlid fishes compose an astonishingly large number of species and formed species flocks in record-breaking time. To facilitate efficient genome scans and comparisons of cichlid genomes, we constructed a medium-density genetic linkage map of microsatellite markers of Astatotilapia burtoni. The mapping cross was derived from two inbred laboratory lines to obtain F(2) progeny by intercrossing. The map revealed 25 linkage groups spanning 1249.3 cM of the genome (size approximately 950 Mb) with an average marker spacing of 6.12 cM. The seven Hox clusters, ParaHox C1, and two paralogs of Pdgfrbeta were mapped to different linkage groups, thus supporting the hypothesis of a teleost-specific genome duplication. The A. burtoni linkage map was compared to the other two available maps for cichlids using shared markers that showed conservation and synteny among East African cichlid genomes. Interesting candidate genes for cichlid speciation were mapped using SNP markers.
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Ward MN, Churcher AM, Dick KJ, Laver CRJ, Owens GL, Polack MD, Ward PR, Breden F, Taylor JS. The molecular basis of color vision in colorful fish: four long wave-sensitive (LWS) opsins in guppies (Poecilia reticulata) are defined by amino acid substitutions at key functional sites. BMC Evol Biol 2008; 8:210. [PMID: 18638376 PMCID: PMC2527612 DOI: 10.1186/1471-2148-8-210] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2008] [Accepted: 07/18/2008] [Indexed: 11/11/2022] Open
Abstract
BACKGROUND Comparisons of functionally important changes at the molecular level in model systems have identified key adaptations driving isolation and speciation. In cichlids, for example, long wavelength-sensitive (LWS) opsins appear to play a role in mate choice and male color variation within and among species. To test the hypothesis that the evolution of elaborate coloration in male guppies (Poecilia reticulata) is also associated with opsin gene diversity, we sequenced long wavelength-sensitive (LWS) opsin genes in six species of the family Poeciliidae. RESULTS Sequences of four LWS opsin genes were amplified from the guppy genome and from mRNA isolated from adult guppy eyes. Variation in expression was quantified using qPCR. Three of the four genes encode opsins predicted to be most sensitive to different wavelengths of light because they vary at key amino acid positions. This family of LWS opsin genes was produced by a diversity of duplication events. One, an intronless gene, was produced prior to the divergence of families Fundulidae and Poeciliidae. Between-gene PCR and DNA sequencing show that two of the guppy LWS opsins are linked in an inverted orientation. This inverted tandem duplication event occurred near the base of the poeciliid tree in the common ancestor of Poecilia and Xiphophorus. The fourth sequence has been uncovered only in the genus Poecilia. In the guppies surveyed here, this sequence is a hybrid, with the 5' end most similar to one of the tandem duplicates and the 3' end identical to the other. CONCLUSION Enhanced wavelength discrimination, a possible consequence of opsin gene duplication and divergence, might have been an evolutionary prerequisite for color-based sexual selection and have led to the extraordinary coloration now observed in male guppies and in many other poeciliids.
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Affiliation(s)
- Matthew N Ward
- University of Victoria, Department of Biology, Victoria, British Columbia, Canada
| | - Allison M Churcher
- University of Victoria, Department of Biology, Victoria, British Columbia, Canada
| | - Kevin J Dick
- University of Victoria, Department of Biology, Victoria, British Columbia, Canada
| | - Chris RJ Laver
- University of Victoria, Department of Biology, Victoria, British Columbia, Canada
| | - Greg L Owens
- University of Victoria, Department of Biology, Victoria, British Columbia, Canada
| | - Megan D Polack
- University of Victoria, Department of Biology, Victoria, British Columbia, Canada
| | - Pam R Ward
- University of Victoria, Department of Biology, Victoria, British Columbia, Canada
| | - Felix Breden
- Simon Fraser University, Department of Biological Sciences, Burnaby, British Columbia, Canada
| | - John S Taylor
- University of Victoria, Department of Biology, Victoria, British Columbia, Canada
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Loh YHE, Katz LS, Mims MC, Kocher TD, Yi SV, Streelman JT. Comparative analysis reveals signatures of differentiation amid genomic polymorphism in Lake Malawi cichlids. Genome Biol 2008; 9:R113. [PMID: 18616806 PMCID: PMC2530870 DOI: 10.1186/gb-2008-9-7-r113] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2008] [Revised: 06/19/2008] [Accepted: 07/10/2008] [Indexed: 11/25/2022] Open
Abstract
Low coverage survey sequencing shows that although Lake Malawi cichlids are phenotypically and behaviorally diverse, they appear genetically like a subdivided population. Background Cichlid fish from East Africa are remarkable for phenotypic and behavioral diversity on a backdrop of genomic similarity. In 2006, the Joint Genome Institute completed low coverage survey sequencing of the genomes of five phenotypically and ecologically diverse Lake Malawi species. We report a computational and comparative analysis of these data that provides insight into the mechanisms that make closely related species different from one another. Results We produced assemblies for the five species ranging in aggregate length from 68 to 79 megabase pairs, identified putative orthologs for more than 12,000 human genes, and predicted more than 32,000 cross-species single nucleotide polymorphisms (SNPs). Nucleotide diversity was lower than that found among laboratory strains of the zebrafish. We collected around 36,000 genotypes to validate a subset of SNPs within and among populations and across multiple individuals of about 75 Lake Malawi species. Notably, there were no fixed differences observed between focal species nor between major lineages. Roughly 3% to 5% of loci surveyed are statistical outliers for genetic differentiation (FST) within species, between species, and between major lineages. Outliers for FST are candidate genes that may have experienced a history of natural selection in the Malawi lineage. Conclusion We present a novel genome sequencing strategy, which is useful when evolutionary diversity is the question of interest. Lake Malawi cichlids are phenotypically and behaviorally diverse, but they appear genetically like a subdivided population. The unique structure of Lake Malawl cichlid genomes should facilitate conceptually new experiments, employing SNPs to identity genotype-phenotype association, using the entire species flock as a mapping panel.
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Affiliation(s)
- Yong-Hwee E Loh
- School of Biology, Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, 315 Ferst Drive, Atlanta, Georgia 30332, USA.
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Pierotti ME, Knight ME, Immler S, Barson NJ, Turner GF, Seehausen O. Individual variation in male mating preferences for female coloration in a polymorphic cichlid fish. Behav Ecol 2008. [DOI: 10.1093/beheco/arm154] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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50
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Salzburger W, Renn SCP, Steinke D, Braasch I, Hofmann HA, Meyer A. Annotation of expressed sequence tags for the East African cichlid fish Astatotilapia burtoni and evolutionary analyses of cichlid ORFs. BMC Genomics 2008; 9:96. [PMID: 18298844 PMCID: PMC2279125 DOI: 10.1186/1471-2164-9-96] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2007] [Accepted: 02/25/2008] [Indexed: 11/13/2022] Open
Abstract
Background The cichlid fishes in general, and the exceptionally diverse East African haplochromine cichlids in particular, are famous examples of adaptive radiation and explosive speciation. Here we report the collection and annotation of more than 12,000 expressed sequence tags (ESTs) generated from three different cDNA libraries obtained from the East African haplochromine cichlid species Astatotilapia burtoni and Metriaclima zebra. Results We first annotated more than 12,000 newly generated cichlid ESTs using the Gene Ontology classification system. For evolutionary analyses, we combined these ESTs with all available sequence data for haplochromine cichlids, which resulted in a total of more than 45,000 ESTs. The ESTs represent a broad range of molecular functions and biological processes. We compared the haplochromine ESTs to sequence data from those available for other fish model systems such as pufferfish (Takifugu rubripes and Tetraodon nigroviridis), trout, and zebrafish. We characterized genes that show a faster or slower rate of base substitutions in haplochromine cichlids compared to other fish species, as this is indicative of a relaxed or reinforced selection regime. Four of these genes showed the signature of positive selection as revealed by calculating Ka/Ks ratios. Conclusion About 22% of the surveyed ESTs were found to have cichlid specific rate differences suggesting that these genes might play a role in lineage specific characteristics of cichlids. We also conclude that the four genes with a Ka/Ks ratio greater than one appear as good candidate genes for further work on the genetic basis of evolutionary success of haplochromine cichlid fishes.
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Affiliation(s)
- Walter Salzburger
- Lehrstuhl für Zoologie und Evolutionsbiologie, Department of Biology, University of Konstanz, 78467 Konstanz, Germany.
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