1
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Dunker JC, St. John ME, Martin CH. Phenotypic covariation predicts diversification in an adaptive radiation of pupfishes. Ecol Evol 2024; 14:e11642. [PMID: 39114171 PMCID: PMC11303982 DOI: 10.1002/ece3.11642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 06/07/2024] [Accepted: 06/12/2024] [Indexed: 08/10/2024] Open
Abstract
Phenotypic covariation among suites of traits may constrain or promote diversification both within and between species, yet few studies have empirically tested this relationship. In this study, we investigate whether phenotypic covariation of craniofacial traits is associated with diversification in an adaptive radiation of pupfishes found only on San Salvador Island, Bahamas (SSI). The radiation includes generalist, durophagous, and lepidophagous species. We compared phenotypic variation and covariation (i.e., the P matrix) between (1) allopatric populations of generalist pupfish from neighboring islands and estuaries in the Caribbean, (2) SSI pupfish allopatric lake populations with only generalist pupfish, and (3) SSI lake populations containing the full radiation in sympatry. Additionally, we examine patterns observed in the P matrices of two independent lab-reared F2 hybrid crosses of the two most morphologically distinct members of the radiation to make inferences about the underlying mechanisms contributing to the variation in craniofacial traits in SSI pupfishes. We found that the P matrix of SSI allopatric generalist populations exhibited higher levels of mean trait correlation, constraints, and integration with simultaneously lower levels of flexibility compared to allopatric generalist populations on other Caribbean islands and sympatric populations of all three species on SSI. We also document that while many craniofacial traits appear to result from additive genetic effects, variation in key traits such as head depth, maxilla length, and lower jaw length may be produced via non-additive genetic mechanisms. Ultimately, this study suggests that differences in phenotypic covariation significantly contribute to producing and maintaining organismal diversity.
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Affiliation(s)
- Julia C. Dunker
- Department of Integrative BiologyUniversity of CaliforniaBerkeleyCaliforniaUSA
| | - Michelle E. St. John
- Department of Integrative BiologyUniversity of CaliforniaBerkeleyCaliforniaUSA
- Present address:
Department of BiologyUniversity of OklahomaNormanOklahomaUSA
| | - Christopher H. Martin
- Department of Integrative BiologyUniversity of CaliforniaBerkeleyCaliforniaUSA
- Museum of Vertebrate ZoologyUniversity of CaliforniaBerkeleyCaliforniaUSA
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2
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St John ME, Dunker JC, Richards EJ, Romero S, Martin CH. Parallel evolution of integrated craniofacial traits in trophic specialist pupfishes. Ecol Evol 2024; 14:e11640. [PMID: 38979003 PMCID: PMC11228360 DOI: 10.1002/ece3.11640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Revised: 05/14/2024] [Accepted: 06/13/2024] [Indexed: 07/10/2024] Open
Abstract
Populations may adapt to similar environments via parallel or non-parallel genetic changes, but the frequency of these alternative mechanisms and underlying contributing factors are still poorly understood outside model systems. We used QTL mapping to investigate the genetic basis of highly divergent craniofacial traits between the scale-eater (Cyprinodon desquamator) and molluscivore (C. brontotheroides) pupfish adapting to two different hypersaline lake environments on San Salvador Island, Bahamas. We lab-reared F2 scale-eater x molluscivore intercrosses from two different lake populations, estimated linkage maps, scanned for significant QTL for 29 skeletal and craniofacial traits, female mate preference, and sex. We compared the location of QTL between lakes to quantify parallel and non-parallel genetic changes. We detected significant QTL for six craniofacial traits in at least one lake. However, nearly all shared QTL loci were associated with a different craniofacial trait within each lake. Therefore, our estimate of parallel evolution of craniofacial genetic architecture could range from one out of six identical trait QTL (low parallelism) to five out of six integrated trait QTL (high parallelism). We suggest that pleiotropy and trait integration can affect estimates of parallel evolution, particularly within rapid radiations. We also observed increased adaptive introgression in shared QTL regions, suggesting that gene flow contributed to parallel evolution. Overall, our results suggest that the same genomic regions may contribute to parallel adaptation across integrated suites of craniofacial traits, rather than specific traits, and highlight the need for a more expansive definition of parallel evolution.
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Affiliation(s)
| | - Julia C Dunker
- Department of Integrative Biology University of California Berkeley California USA
| | - Emilie J Richards
- Department of Ecology, Evolution and Behavior University of Minnesota Minneapolis Minnesota USA
| | - Stephanie Romero
- Department of Evolution and Ecology University of California Davis California USA
| | - Christopher H Martin
- Department of Integrative Biology University of California Berkeley California USA
- Museum of Vertebrate Zoology University of California Berkeley California USA
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3
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Borin JM, Lee JJ, Lucia-Sanz A, Gerbino KR, Weitz JS, Meyer JR. Rapid bacteria-phage coevolution drives the emergence of multiscale networks. Science 2023; 382:674-678. [PMID: 37943920 DOI: 10.1126/science.adi5536] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Accepted: 09/28/2023] [Indexed: 11/12/2023]
Abstract
Interactions between species catalyze the evolution of multiscale ecological networks, including both nested and modular elements that regulate the function of diverse communities. One common assumption is that such complex pattern formation requires spatial isolation or long evolutionary timescales. We show that multiscale network structure can evolve rapidly under simple ecological conditions without spatial structure. In just 21 days of laboratory coevolution, Escherichia coli and bacteriophage Φ21 coevolve and diversify to form elaborate cross-infection networks. By measuring ~10,000 phage-bacteria infections and testing the genetic basis of interactions, we identify the mechanisms that create each component of the multiscale pattern. Our results demonstrate how multiscale networks evolve in parasite-host systems, illustrating Darwin's idea that simple adaptive processes can generate entangled banks of ecological interactions.
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Affiliation(s)
- Joshua M Borin
- Division of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Justin J Lee
- Division of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Adriana Lucia-Sanz
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Krista R Gerbino
- Division of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Joshua S Weitz
- Department of Biology, University of Maryland, College Park, MD 20742, USA
- Department of Physics, University of Maryland, College Park, MD 20742, USA
- Institut de Biologie, École Normale Supérieure, 75005 Paris, France
| | - Justin R Meyer
- Division of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
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4
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Moons T, Kmentová N, Pariselle A, Artois T, Bert W, Vanhove MP, Cruz-Laufer AJ. All quiet on the western front? The evolutionary history of monogeneans (Dactylogyridae: Cichlidogyrus, Onchobdella) infecting a West and Central African tribe of cichlid fishes (Chromidotilapiini). Parasite 2023; 30:25. [PMID: 37404116 PMCID: PMC10321234 DOI: 10.1051/parasite/2023023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 05/21/2023] [Indexed: 07/06/2023] Open
Abstract
Owing to the largely unexplored diversity of metazoan parasites, their speciation mechanisms and the circumstances under which such speciation occurs - in allopatry or sympatry - remain vastly understudied. Cichlids and their monogenean flatworm parasites have previously served as a study system for macroevolutionary processes, e.g., for the role of East African host radiations on parasite communities. Here, we investigate the diversity and evolution of the poorly explored monogeneans infecting a West and Central African lineage of cichlid fishes: Chromidotilapiini, which is the most species-rich tribe of cichlids in this region. We screened gills of 149 host specimens (27 species) from natural history collections and measured systematically informative characters of the sclerotised attachment and reproductive organs of the parasites. Ten monogenean species (Dactylogyridae: Cichlidogyrus and Onchobdella) were found, eight of which are newly described and one redescribed herein. The phylogenetic positions of chromidotilapiines-infecting species of Cichlidogyrus were inferred through a parsimony analysis of the morphological characters. Furthermore, we employed machine learning algorithms to detect morphological features associated with the main lineages of Cichlidogyrus. Although the results of these experimental algorithms remain inconclusive, the parsimony analysis indicates that West and Central African lineages of Cichlidogyrus and Onchobdella are monophyletic, unlike the paraphyletic host lineages. Several instances of host sharing suggest occurrences of intra-host speciation (sympatry) and host switching (allopatry). Some morphological variation was recorded that may also indicate the presence of species complexes. We conclude that collection material can provide important insights on parasite evolution despite the lack of well-preserved DNA material.
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Affiliation(s)
- Tanisha Moons
- UHasselt – Hasselt University, Faculty of Sciences, Centre for Environmental Sciences, Research Group Zoology: Biodiversity and Toxicology, Agoralaan Gebouw D 3590 Diepenbeek Belgium
- Nematology Research Unit, Department of Biology, Ghent University K.L. Ledeganckstraat 35 9000 Ghent Belgium
- Department of Parasitology, Faculty of Science, University of South Bohemia České Budějovice 37005 Czech Republic
| | - Nikol Kmentová
- UHasselt – Hasselt University, Faculty of Sciences, Centre for Environmental Sciences, Research Group Zoology: Biodiversity and Toxicology, Agoralaan Gebouw D 3590 Diepenbeek Belgium
| | - Antoine Pariselle
- ISEM, Université de Montpellier, CNRS, IRD 34095 Montpellier France
- Faculty of Sciences, Laboratory “Biodiversity, Ecology and Genome”, Research Centre “Plant and Microbial Biotechnology, Biodiversity and Environment”, Mohammed V University 10000 Rabat Morocco
| | - Tom Artois
- UHasselt – Hasselt University, Faculty of Sciences, Centre for Environmental Sciences, Research Group Zoology: Biodiversity and Toxicology, Agoralaan Gebouw D 3590 Diepenbeek Belgium
| | - Wim Bert
- Nematology Research Unit, Department of Biology, Ghent University K.L. Ledeganckstraat 35 9000 Ghent Belgium
| | - Maarten P.M. Vanhove
- UHasselt – Hasselt University, Faculty of Sciences, Centre for Environmental Sciences, Research Group Zoology: Biodiversity and Toxicology, Agoralaan Gebouw D 3590 Diepenbeek Belgium
| | - Armando J. Cruz-Laufer
- UHasselt – Hasselt University, Faculty of Sciences, Centre for Environmental Sciences, Research Group Zoology: Biodiversity and Toxicology, Agoralaan Gebouw D 3590 Diepenbeek Belgium
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5
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Sun N, Yang L, Tian F, Zeng H, He Z, Zhao K, Wang C, Meng M, Feng C, Fang C, Lv W, Bo J, Tang Y, Gan X, Peng Z, Chen Y, He S. Sympatric or micro-allopatric speciation in a glacial lake? Genomic islands support neither. Natl Sci Rev 2022; 9:nwac291. [PMID: 36778108 PMCID: PMC9905650 DOI: 10.1093/nsr/nwac291] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2022] [Revised: 12/19/2022] [Accepted: 12/23/2022] [Indexed: 12/29/2022] Open
Abstract
Apparent cases of sympatric speciation may actually be due to micro-allopatric or micro-parapatric speciation. One way to distinguish between these models is to examine the existence and nature of genomic islands of divergence, wherein divergent DNA segments are interspersed with low-divergence segments. Such islands should be rare or absent under micro-allopatric speciation but common in cases of speciation with gene flow. Sympatric divergence of endemic fishes is known from isolated saline, crater, postglacial, and ancient lakes. Two morphologically distinct cyprinid fishes, Gymnocypris eckloni scoliostomus (GS) and G. eckloni eckloni (GE), in a small glacial lake on the Qinghai-Tibet Plateau, Lake Sunmcuo, match the biogeographic criteria of sympatric speciation. In this study, we examined genome-wide variation in 46 individuals from these two groups. The divergence time between the GS and GE lineages was estimated to be 20-60 Kya. We identified 54 large genomic islands (≥100 kb) of speciation, which accounted for 89.4% of the total length of all genomic islands. These islands harboured divergent genes related to olfactory receptors and olfaction signals that may play important roles in food selection and assortative mating in fishes. Although the genomic islands clearly indicated speciation with gene flow and rejected micro-allopatric speciation, they were too large to support the hypothesis of sympatric speciation. Theoretical and recent empirical studies suggested that continual gene flow in sympatry should give rise to many small genomic islands (as small as a few kilobases in size). Thus, the observed pattern is consistent with the extensive evidence on parapatric speciation, in which adjacent habitats facilitate divergent selection but also permit gene flow during speciation. We suggest that many, if not most, of the reported cases of sympatric speciation are likely to be micro-parapatric speciation.
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Affiliation(s)
| | | | | | | | | | | | - Cheng Wang
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Minghui Meng
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Chenguang Feng
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China,School of Ecology and Environment, Northwestern Polytechnical University, Xi’an 710129, China
| | - Chengchi Fang
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Wenqi Lv
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jing Bo
- Institute of Deep-Sea Science and Engineering, Chinese Academy of Sciences, Sanya 572000, China,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yongtao Tang
- Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining 810008, China
| | - Xiaoni Gan
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Zuogang Peng
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Southwest University School of Life Sciences, Chongqing 400700, China
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6
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Wang X, He Z, Guo Z, Yang M, Xu S, Chen Q, Shao S, Li S, Zhong C, Duke NC, Shi S. Extensive gene flow in secondary sympatry after allopatric speciation. Natl Sci Rev 2022; 9:nwac280. [PMID: 36694801 PMCID: PMC9869077 DOI: 10.1093/nsr/nwac280] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 12/04/2022] [Accepted: 12/10/2022] [Indexed: 12/15/2022] Open
Abstract
In the conventional view, species are separate gene pools delineated by reproductive isolation (RI). In an alternative view, species may also be delineated by a small set of 'speciation genes' without full RI, a view that has gained broad acceptance. A recent survey, however, suggested that the extensive literature on 'speciation with gene flow' is mostly (if not all) about exchanges in the early stages of speciation. There is no definitive evidence that the observed gene flow actually happened after speciation is completed. Here, we wish to know whether 'good species' (defined by the 'secondary sympatry' test) do continue to exchange genes and, importantly, under what conditions such exchanges can be observed. De novo whole-genome assembly and re-sequencing of individuals across the range of two closely related mangrove species (Rhizophora mucronata and R. stylosa) reveal the genomes to be well delineated in allopatry. They became sympatric in northeastern Australia but remain distinct species. Nevertheless, their genomes harbor ∼4000-10 000 introgression blocks averaging only about 3-4 Kb. These fine-grained introgressions indicate continual gene flow long after speciation as non-introgressable 'genomic islets,' ∼1.4 Kb in size, often harbor diverging genes of flower or gamete development. The fine-grained introgression in secondary sympatry may help settle the debate about sympatric vs. micro-allopatric speciation. In conclusion, true 'good species' may often continue to exchange genes but the opportunity for detection is highly constrained.
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Affiliation(s)
| | | | | | - Ming Yang
- Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA98195, USA
| | - Shaohua Xu
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-sen University, Guangzhou510275, China
| | - Qipian Chen
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-sen University, Guangzhou510275, China
| | - Shao Shao
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-sen University, Guangzhou510275, China
| | - Sen Li
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-sen University, Guangzhou510275, China
| | - Cairong Zhong
- Hainan Academy of Forestry (Hainan Academy of Mangrove), Haikou571100, China
| | - Norman C Duke
- Centre for Tropical Water and Aquatic Ecosystem Research, James Cook University, Townsville, QLD 4811, Australia
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7
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Estivals G, Duponchelle F, García-Dávila C, Römer U, Mariac C, Renno JF. Exceptional Genetic Differentiation at a Micro-geographic Scale in Apistogramma agassizii (Steindachner, 1875) from the Peruvian Amazon: Sympatric Speciation? Evol Biol 2022. [DOI: 10.1007/s11692-022-09587-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
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8
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Martin CH. Is sympatric speciation in nature only possible with micro-parapatry? A new case study of glacial lake cyprinid fishes. Natl Sci Rev 2022; 9:nwad006. [PMID: 36751304 PMCID: PMC9894001 DOI: 10.1093/nsr/nwad006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/05/2023] [Indexed: 01/11/2023] Open
Affiliation(s)
- Christopher H Martin
- Department of Integrative Biology, University of California, Berkeley, USA
- Museum of Vertebrate Zoology, University of California, Berkeley, USA
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9
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Galvez JR, St John ME, McLean K, Touokong CD, Gonwouo LN, Martin CH. Trophic specialization on unique resources despite limited niche divergence in a celebrated example of sympatric speciation. ECOLOGY OF FRESHWATER FISH 2022; 31:675-692. [PMID: 36211622 PMCID: PMC9542214 DOI: 10.1111/eff.12661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Accepted: 04/02/2022] [Indexed: 06/16/2023]
Abstract
Trophic niche partitioning is observed in many adaptive radiations and is hypothesized to be a central process underlying species divergence. However, patterns of dietary niche partitioning are inconsistent across radiations and there are few studies of niche partitioning in putative examples of sympatric speciation. Here, we conducted the first quantitative study of dietary niche partitioning using stomach contents and stable isotope analyses in one of the most celebrated examples of sympatric speciation: the cichlid radiation from crater lake Barombi Mbo, Cameroon. We found little evidence for trophic niche partitioning among cichlids, including the nine species coexisting in the narrow littoral zone. Stable isotope analyses supported these conclusions of substantial dietary overlap. Our data, however, did reveal that five of eleven species consume rare dietary items, including freshwater sponge, terrestrial ants, and nocturnal foraging on shrimp. Stomach contents of the spongivore (Pungu maclareni) were 20% freshwater sponge, notable considering that only 0.04% of all fishes consume sponges. Overall, we conclude that cichlid species in lake Barombi Mbo overlap considerably in broad dietary niches-in part due to the large proportion of detritus in the stomach contents of all species-but there is evidence for divergence among species in their diet specializations on unique resources. We speculate that these species may utilize these additional specialized resources during periods of low resource abundance in support of Liem's paradox.
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Affiliation(s)
- Jacquelyn R Galvez
- Department of Integrative Biology, University of California, Berkeley, CA, USA
- Museum of Vertebrate Zoology, University of California, Berkeley, CA, USA
| | - Michelle E St John
- Department of Integrative Biology, University of California, Berkeley, CA, USA
- Museum of Vertebrate Zoology, University of California, Berkeley, CA, USA
| | - Keara McLean
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | | | - Legrand Nono Gonwouo
- Laboratory of Zoology, Faculty of Science, University of Yaoundé I, P.O. Box 812, Yaoundé, Cameroon
| | - Christopher H Martin
- Department of Integrative Biology, University of California, Berkeley, CA, USA
- Museum of Vertebrate Zoology, University of California, Berkeley, CA, USA
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10
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Astudillo-Clavijo V, Stiassny MLJ, Ilves KL, Musilova Z, Salzburger W, López-Fernández H. Exon-based phylogenomics and the relationships of African cichlid fishes: tackling the challenges of reconstructing phylogenies with repeated rapid radiations. Syst Biol 2022; 72:134-149. [PMID: 35880863 DOI: 10.1093/sysbio/syac051] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 07/06/2022] [Accepted: 07/19/2022] [Indexed: 11/13/2022] Open
Abstract
African cichlids (subfamily: Pseudocrenilabrinae) are among the most diverse vertebrates, and their propensity for repeated rapid radiation has made them a celebrated model system in evolutionary research. Nonetheless, despite numerous studies, phylogenetic uncertainty persists, and riverine lineages remain comparatively underrepresented in higher-level phylogenetic studies. Heterogeneous gene histories resulting from incomplete lineage sorting (ILS) and hybridization are likely sources of uncertainty, especially during episodes of rapid speciation. We investigate relationships of Pseudocrenilabrinae and its close relatives while accounting for multiple sources of genetic discordance using species tree and hybrid network analyses with hundreds of single-copy exons. We improve sequence recovery for distant relatives, thereby extending the taxonomic reach of our probes, with a hybrid reference guided/de novo assembly approach. Our analyses provide robust hypotheses for most higher-level relationships and reveal widespread gene heterogeneity, including in riverine taxa. ILS and past hybridization are identified as sources of genetic discordance in different lineages. Sampling of various Blenniiformes (formerly Ovalentaria) adds strong phylogenomic support for convict blennies (Pholidichthyidae) as sister to Cichlidae, and points to other potentially useful protein-coding markers across the order. A reliable phylogeny with representatives from diverse environments will support ongoing taxonomic and comparative evolutionary research in the cichlid model system.
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Affiliation(s)
- Viviana Astudillo-Clavijo
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, M5S 3B2, Canada.,Department of Natural History, Royal Ontario Museum, Toronto, M5S 2C6, Canada.,Department of Ecology and Evolutionary Biology and Museum of Zoology, University of Michigan, Ann Arbor, 48109, USA
| | - Melanie L J Stiassny
- Department of Ichthyology, American Museum of Natural History, New York, 10024-5102, USA
| | - Katriina L Ilves
- Research & Collections, Zoology, Canadian Museum of Nature, Ottawa, K1P 6P4, Canada
| | - Zuzana Musilova
- Department of Zoology, Charles University in Prague, Vinicna 7, Prague, CZ-128 44, Czech Republic
| | - Walter Salzburger
- Zoological Institute, University of Basel, Vesalgasse 1, CH-4051, Basel, Switzerland
| | - Hernán López-Fernández
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, M5S 3B2, Canada.,Department of Natural History, Royal Ontario Museum, Toronto, M5S 2C6, Canada.,Department of Ecology and Evolutionary Biology and Museum of Zoology, University of Michigan, Ann Arbor, 48109, USA
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11
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Patton AH, Richards EJ, Gould KJ, Buie LK, Martin CH. Hybridization alters the shape of the genotypic fitness landscape, increasing access to novel fitness peaks during adaptive radiation. eLife 2022; 11:e72905. [PMID: 35616528 PMCID: PMC9135402 DOI: 10.7554/elife.72905] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 04/14/2022] [Indexed: 12/30/2022] Open
Abstract
Estimating the complex relationship between fitness and genotype or phenotype (i.e. the adaptive landscape) is one of the central goals of evolutionary biology. However, adaptive walks connecting genotypes to organismal fitness, speciation, and novel ecological niches are still poorly understood and processes for surmounting fitness valleys remain controversial. One outstanding system for addressing these connections is a recent adaptive radiation of ecologically and morphologically novel pupfishes (a generalist, molluscivore, and scale-eater) endemic to San Salvador Island, Bahamas. We leveraged whole-genome sequencing of 139 hybrids from two independent field fitness experiments to identify the genomic basis of fitness, estimate genotypic fitness networks, and measure the accessibility of adaptive walks on the fitness landscape. We identified 132 single nucleotide polymorphisms (SNPs) that were significantly associated with fitness in field enclosures. Six out of the 13 regions most strongly associated with fitness contained differentially expressed genes and fixed SNPs between trophic specialists; one gene (mettl21e) was also misexpressed in lab-reared hybrids, suggesting a potential intrinsic genetic incompatibility. We then constructed genotypic fitness networks from adaptive alleles and show that scale-eating specialists are the most isolated of the three species on these networks. Intriguingly, introgressed and de novo variants reduced fitness landscape ruggedness as compared to standing variation, increasing the accessibility of genotypic fitness paths from generalist to specialists. Our results suggest that adaptive introgression and de novo mutations alter the shape of the fitness landscape, providing key connections in adaptive walks circumventing fitness valleys and triggering the evolution of novelty during adaptive radiation.
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Affiliation(s)
- Austin H Patton
- Department of Integrative Biology, University of California, BerkeleyBerkeleyUnited States
- Museum of Vertebrate Zoology, University of California, BerkeleyBerkeleyUnited States
| | - Emilie J Richards
- Department of Integrative Biology, University of California, BerkeleyBerkeleyUnited States
- Museum of Vertebrate Zoology, University of California, BerkeleyBerkeleyUnited States
| | - Katelyn J Gould
- Department of Biology, University of North CarolinaChapel HillUnited States
| | - Logan K Buie
- Department of Biology, University of North CarolinaChapel HillUnited States
| | - Christopher H Martin
- Department of Integrative Biology, University of California, BerkeleyBerkeleyUnited States
- Museum of Vertebrate Zoology, University of California, BerkeleyBerkeleyUnited States
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12
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Porter CK, Benkman CW. Performance tradeoffs and resource availability drive variation in reproductive isolation between sympatrically diverging crossbills. Am Nat 2021; 199:362-379. [DOI: 10.1086/718235] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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13
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Kollár J, Poulíčková A, Dvořák P. On the relativity of species, or the probabilistic solution to the species problem. Mol Ecol 2021; 31:411-418. [PMID: 34626519 DOI: 10.1111/mec.16218] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 09/17/2021] [Accepted: 09/30/2021] [Indexed: 11/28/2022]
Abstract
For centuries, both scientists and philosophers have discussed the nature of species resulting in c. 35 species concepts proposed to date. However, in our opinion, none of them incorporated neither recent advances in evolutionary genomics nor dimensionality of species in befitting depth. Our attempt to do so resulted in the following conclusions. Due to the continuous nature of evolution (regardless of its rate and constancy), species are inevitably undefinable as natural discontinuous units (except those originating in saltatory speciation) whenever the time dimension is taken into consideration. Therefore, the very existence of species as a natural discontinuous entity is relative to its dimensionality. A direct consequence of the relativity of species is the duality of speciators (e.g., incipient species) meaning that, in a given time, they may be perceived as both being and not being a species. Finally, the most accurate way to reflect both the relativity of species and the duality of speciators in species delimitation is probabilistic. While the novelty of these ideas may be questionable, they still deserve more extensive attention from the biological community. Here, we hope to draw such attention by outlining one of the possible pathways towards a new kind of probabilistic species delimitation methods based on the probability of irreversible divergence of evolutionary lineages. We anticipate that our probabilistic view of speciation has the potential to facilitate some of the most serious and universal issues of current taxonomy and to ensure unity of the species-level taxonomy across the tree of life.
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Affiliation(s)
- Jan Kollár
- Department of Botany, Faculty of Science, Palacký University Olomouc, Olomouc, Czech Republic
| | - Aloisie Poulíčková
- Department of Botany, Faculty of Science, Palacký University Olomouc, Olomouc, Czech Republic
| | - Petr Dvořák
- Department of Botany, Faculty of Science, Palacký University Olomouc, Olomouc, Czech Republic
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14
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St John CA, Buser TJ, Kee VE, Kirilchik S, Bogdanov B, Neely D, Sandel M, Aguilar A. Diversification along a benthic to pelagic gradient contributes to fish diversity in the world's largest lake (Lake Baikal, Russia). Mol Ecol 2021; 31:238-251. [PMID: 34614231 DOI: 10.1111/mec.16209] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 09/03/2021] [Accepted: 09/28/2021] [Indexed: 12/16/2022]
Abstract
Insights into the generation of diversity in both plants and animals have relied heavily on studying speciation in adaptive radiations. Russia's Lake Baikal has facilitated a putative adaptive radiation of cottid fishes (sculpins), some of which are highly specialized to inhabit novel niches created by the lake's unique geology and ecology. Here, we test evolutionary relationships and novel morphological adaptation in a piece of this radiation: the Baikal cottid genus, Cottocomephorus, a morphologically derived benthopelagic genus of three described species. We used a combination of mitochondrial DNA and restriction site associated DNA sequencing from all Cottocomephorus species. Analysis of mitochondrial cytochrome b haplotypes was only able to two resolve two lineages: C. grewingkii and C. comephoroides/inermis. Phylogenetic inference, principal component analysis, and faststructure of genome-wide SNPs uncovered three lineages within Cottocomephorus: C. comephoroides, C. inermis and C. grewingkii. We found recent divergence and admixture between C. comephoroides and C. inermis and deep divergence between these two species and C. grewingkii. Contrasting other fish radiations, we found no evidence of ancient hybridization among Cottocomephorus species. Digital morphology revealed highly derived pelagic phenotypes that reflect divergence by specialization to the benthopelagic niche in Cottocomephorus. Among Cottocomephorus species, we found evidence of ongoing adaptation to the pelagic zone. This pattern highlights the importance of speciation along a benthic-pelagic gradient seen in Cottocomephorus and across other adaptive fish radiations.
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Affiliation(s)
- Carl A St John
- Department of Biological Science, California State University Los Angeles, Los Angeles, California, USA
| | - Thaddaeus J Buser
- Department of Fisheries and Wildlife, Oregon State University, Corvallis, Oregon, USA
| | - Victoria E Kee
- Department of Fisheries and Wildlife, Oregon State University, Corvallis, Oregon, USA
| | - Sergei Kirilchik
- Limnological Institute, Russian Academy of Sciences, Irkutsk, Russia
| | - Bakhtiar Bogdanov
- Limnological Institute, Russian Academy of Sciences, Irkutsk, Russia
| | - David Neely
- Tennessee Aquarium Conservation Institute, Chattanooga, Tennessee, USA
| | - Michael Sandel
- Biological and Environmental Sciences, University of Western Alabama, Livingston, Alabama, USA
| | - Andres Aguilar
- Department of Biological Science, California State University Los Angeles, Los Angeles, California, USA
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15
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Barley AJ, Reeder TW, Nieto-Montes de Oca A, Cole CJ, Thomson RC. A New Diploid Parthenogenetic Whiptail Lizard from Sonora, Mexico, Is the "Missing Link" in the Evolutionary Transition to Polyploidy. Am Nat 2021; 198:295-309. [PMID: 34260872 DOI: 10.1086/715056] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
AbstractTransitions between sexual and unisexual reproductive modes have significant consequences for the evolutionary trajectories of species. These transitions have occurred numerous times in vertebrates and are frequently mediated by hybridization events. Triploid unisexual vertebrates are thought to arise through hybridization between individuals of a diploid unisexual lineage and a sexual species, although additional evidence that confirms this mechanism is needed in numerous groups. North American whiptail lizards (Aspidoscelis) are notable for being one of the largest radiations of unisexual vertebrates, and the most diverse group of Aspidoscelis includes numerous triploid lineages that have no known diploid unisexual ancestors. This pattern of "missing" ancestors may result from the short evolutionary life span of unisexual lineages or the selective advantages of polyploidy, or it could suggest that alternative mechanisms of triploid formation are operating in nature. We leverage genomic, morphological, and karyotypic data to describe a new diploid unisexual whiptail and show that it is likely the unisexual progenitor of an extant triploid lineage, A. opatae. We also resolve patterns of polyploidization within the A. sexlineatus species group and test predictions about the phenotypic outcomes of hybridization.
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16
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Svardal H, Salzburger W, Malinsky M. Genetic Variation and Hybridization in Evolutionary Radiations of Cichlid Fishes. Annu Rev Anim Biosci 2020; 9:55-79. [PMID: 33197206 DOI: 10.1146/annurev-animal-061220-023129] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Evolutionary radiations are responsible for much of the variation in biodiversity across taxa. Cichlid fishes are well known for spectacular evolutionary radiations, as they have repeatedly evolved into large and phenotypically diverse arrays of species. Cichlid genomes carry signatures of past events and, at the same time, are the substrate for ongoing evolution. We survey genome-wide data and the available literature covering 438 cichlid populations (412 species) across multiple radiations to synthesize information about patterns and sharing of genetic variation. Nucleotide diversity within species is low in cichlids, with 92% of surveyed populations having less diversity than the median value found in other vertebrates. Divergence within radiations is also low, and a large proportion of variation is shared among species due to incomplete lineage sorting and widespread hybridization. Population genetics therefore provides a suitable conceptual framework for evolutionary genomic studies of cichlid radiations. We focus in detail on the roles of hybridization in shaping the patterns of genetic variation and in promoting cichlid diversification.
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Affiliation(s)
- Hannes Svardal
- Department of Biology, University of Antwerp, 2020 Antwerp, Belgium; .,Naturalis Biodiversity Center, 2333 Leiden, The Netherlands
| | - Walter Salzburger
- Zoological Institute, University of Basel, 4051 Basel, Switzerland; ,
| | - Milan Malinsky
- Zoological Institute, University of Basel, 4051 Basel, Switzerland; ,
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17
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Choi JY, Purugganan M, Stacy EA. Divergent Selection and Primary Gene Flow Shape Incipient Speciation of a Riparian Tree on Hawaii Island. Mol Biol Evol 2020; 37:695-710. [PMID: 31693149 PMCID: PMC7038655 DOI: 10.1093/molbev/msz259] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
A long-standing goal of evolutionary biology is to understand the mechanisms underlying the formation of species. Of particular interest is whether or not speciation can occur in the presence of gene flow and without a period of physical isolation. Here, we investigated this process within Hawaiian Metrosideros, a hypervariable and highly dispersible woody species complex that dominates the Hawaiian Islands in continuous stands. Specifically, we investigated the origin of Metrosideros polymorpha var. newellii (newellii), a riparian ecotype endemic to Hawaii Island that is purportedly derived from the archipelago-wide M. polymorpha var. glaberrima (glaberrima). Disruptive selection across a sharp forest-riparian ecotone contributes to the isolation of these varieties and is a likely driver of newellii's origin. We examined genome-wide variation of 42 trees from Hawaii Island and older islands. Results revealed a split between glaberrima and newellii within the past 0.3-1.2 My. Admixture was extensive between lineages within Hawaii Island and between islands, but introgression from populations on older islands (i.e., secondary gene flow) did not appear to contribute to the emergence of newellii. In contrast, recurrent gene flow (i.e., primary gene flow) between glaberrima and newellii contributed to the formation of genomic islands of elevated absolute and relative divergence. These regions were enriched for genes with regulatory functions as well as for signals of positive selection, especially in newellii, consistent with divergent selection underlying their formation. In sum, our results support riparian newellii as a rare case of incipient ecological speciation with primary gene flow in trees.
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Affiliation(s)
- Jae Young Choi
- Center for Genomics and Systems Biology, Department of Biology, New York University, New York, NY
| | - Michael Purugganan
- Center for Genomics and Systems Biology, Department of Biology, New York University, New York, NY.,Center for Genomics and Systems Biology, NYU Abu Dhabi Research Institute, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Elizabeth A Stacy
- School of Life Sciences, University of Nevada, Las Vegas, Las Vegas, NV
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18
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Gillespie RG, Bennett GM, De Meester L, Feder JL, Fleischer RC, Harmon LJ, Hendry AP, Knope ML, Mallet J, Martin C, Parent CE, Patton AH, Pfennig KS, Rubinoff D, Schluter D, Seehausen O, Shaw KL, Stacy E, Stervander M, Stroud JT, Wagner C, Wogan GOU. Comparing Adaptive Radiations Across Space, Time, and Taxa. J Hered 2020; 111:1-20. [PMID: 31958131 PMCID: PMC7931853 DOI: 10.1093/jhered/esz064] [Citation(s) in RCA: 105] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 10/28/2019] [Indexed: 01/02/2023] Open
Abstract
Adaptive radiation plays a fundamental role in our understanding of the evolutionary process. However, the concept has provoked strong and differing opinions concerning its definition and nature among researchers studying a wide diversity of systems. Here, we take a broad view of what constitutes an adaptive radiation, and seek to find commonalities among disparate examples, ranging from plants to invertebrate and vertebrate animals, and remote islands to lakes and continents, to better understand processes shared across adaptive radiations. We surveyed many groups to evaluate factors considered important in a large variety of species radiations. In each of these studies, ecological opportunity of some form is identified as a prerequisite for adaptive radiation. However, evolvability, which can be enhanced by hybridization between distantly related species, may play a role in seeding entire radiations. Within radiations, the processes that lead to speciation depend largely on (1) whether the primary drivers of ecological shifts are (a) external to the membership of the radiation itself (mostly divergent or disruptive ecological selection) or (b) due to competition within the radiation membership (interactions among members) subsequent to reproductive isolation in similar environments, and (2) the extent and timing of admixture. These differences translate into different patterns of species accumulation and subsequent patterns of diversity across an adaptive radiation. Adaptive radiations occur in an extraordinary diversity of different ways, and continue to provide rich data for a better understanding of the diversification of life.
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Affiliation(s)
- Rosemary G Gillespie
- University of California, Berkeley, Essig Museum of Entomology & Department of Environmental Science, Policy, and Management, Berkeley, CA
| | - Gordon M Bennett
- University of California Merced, Life and Environmental Sciences Unit, Merced, CA
| | - Luc De Meester
- University of Leuven, Laboratory of Aquatic Ecology, Evolution and Conservation, Leuven, Belguim
| | - Jeffrey L Feder
- University of Notre Dame, Dept. of Biological Sciences, Notre Dame, IN
| | - Robert C Fleischer
- Center for Conservation Genomics, Smithsonian Conservation Biology Institute, National Zoological Park, Washington, DC
| | - Luke J Harmon
- University of Idaho, Dept. of Biological Sciences, Moscow, ID
| | | | | | | | - Christopher Martin
- University of California Berkeley, Integrative Biology and Museum of Vertebrate Zoology, Berkeley, CA
| | | | - Austin H Patton
- Washington State University, School of Biological Sciences, Pullman, WA
| | - Karin S Pfennig
- University of North Carolina at Chapel Hill, Department of Biology, Chapel Hill, NC
| | - Daniel Rubinoff
- University of Hawaiʻi at Manoa, Department of Plant and Environmental Protection Sciences, Honolulu, HI
| | | | - Ole Seehausen
- Institute of Ecology & Evolution, University of Bern, Bern, BE, Switzerland
- Center for Ecology, Evolution & Biogeochemistry, Eawag, Kastanienbaum, LU, Switzerland
| | - Kerry L Shaw
- Cornell University, Neurobiology and Behavior, Tower Road,, Ithaca, NY
| | - Elizabeth Stacy
- University of Nevada Las Vegas, School of Life Sciences, Las Vegas, NV
| | - Martin Stervander
- University of Oregon, Institute of Ecology and Evolution, Eugene, OR
| | - James T Stroud
- Washington University in Saint Louis, Biology, Saint Louis, MO
| | | | - Guinevere O U Wogan
- University of California Berkeley, Environmental Science Policy, and Management, Berkeley, CA
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19
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Carleton KL, Escobar-Camacho D, Kocher TD. Visual adaptation could aid sympatric speciation in a deep crater lake. Mol Ecol 2019; 28:5007-5009. [PMID: 31749242 DOI: 10.1111/mec.15278] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 10/14/2019] [Indexed: 01/26/2023]
Abstract
Allopatric speciation was originally suggested to be the primary mechanism of animal speciation (Mayr, 1942; Figure 1). During allopatric speciation, populations diverge when gene flow is reduced across significant biogeographic barriers. Sympatric speciation, where species diverge while inhabiting the same location, was thought to be essentially impossible. However, the advent of theoretical models followed by new experimental evidence made sympatric speciation more plausible (Via, 2001). The cichlid fishes of Barombi Mbo, a small crater lake in western Cameroon, became one of the most widely accepted examples of sympatric speciation (Schliewen, Tautz, & Paabo, 1994). Although the phylogenetic history of this clade is not quite as simple as originally thought, it remains one of the best examples of sympatric speciation (Richards, Poelstra, & Martin, 2018). However, little is known about the molecular mechanisms contributing to the splitting of these species in situ. In a From the Cover article in this issue of Molecular Ecology, Musilova et al. (2019) focus on the diversity of visual systems among these fishes. They identify genetic changes associated with several aspects of visual adaptation that may have contributed to the ecological specialization and sympatric speciation of cichlids in this lake.
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Affiliation(s)
- Karen L Carleton
- Department of Biology, University of Maryland, College Park, Maryland
| | | | - Thomas D Kocher
- Department of Biology, University of Maryland, College Park, Maryland
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20
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MARTIN CHRISTOPHERH, RICHARDS EMILIEJ. The paradox behind the pattern of rapid adaptive radiation: how can the speciation process sustain itself through an early burst? ANNUAL REVIEW OF ECOLOGY, EVOLUTION, AND SYSTEMATICS 2019; 50:569-593. [PMID: 36237480 PMCID: PMC9555815 DOI: 10.1146/annurev-ecolsys-110617-062443] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/27/2023]
Abstract
Rapid adaptive radiation poses a distinct question apart from speciation and adaptation: what happens after one speciation event? That is, how are some lineages able to continue speciating through a rapid burst? This question connects global macroevolutionary patterns to microevolutionary processes. Here we review major features of rapid radiations in nature and their mismatch with theoretical models and what is currently known about speciation mechanisms. Rapid radiations occur on three major diversification axes - species richness, phenotypic disparity, and ecological diversity - with exceptional outliers on each axis. The paradox is that the hallmark early stage of adaptive radiation, a rapid burst of speciation and niche diversification, is contradicted by most existing speciation models which instead predict continuously decelerating speciation rates and niche subdivision through time. Furthermore, while speciation mechanisms such as magic traits, phenotype matching, and physical linkage of co-adapted alleles promote speciation, it is often not discussed how these mechanisms could promote multiple speciation events in rapid succession. Additional mechanisms beyond ecological opportunity are needed to understand how rapid radiations occur. We review the evidence for five emerging theories: 1) the 'transporter' hypothesis: introgression and the ancient origins of adaptive alleles, 2) the 'signal complexity' hypothesis: the dimensionality of sexual traits, 3) the connectivity of fitness landscapes, 4) 'diversity begets diversity', and 5) flexible stem/'plasticity first'. We propose new questions and predictions to guide future work on the mechanisms underlying the rare origins of rapid radiation.
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Affiliation(s)
- CHRISTOPHER H. MARTIN
- Department of Biology, University of North Carolina at Chapel Hill, NC, USA
- Integrative Biology and Museum of Vertebrate Zoology, University of California, Berkeley, CA, USA
| | - EMILIE J. RICHARDS
- Department of Biology, University of North Carolina at Chapel Hill, NC, USA
- Integrative Biology and Museum of Vertebrate Zoology, University of California, Berkeley, CA, USA
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21
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Majtánová Z, Indermaur A, Nyom ARB, Ráb P, Musilova Z. Adaptive Radiation from a Chromosomal Perspective: Evidence of Chromosome Set Stability in Cichlid Fishes (Cichlidae: Teleostei) from the Barombi Mbo Lake, Cameroon. Int J Mol Sci 2019; 20:ijms20204994. [PMID: 31601021 PMCID: PMC6834198 DOI: 10.3390/ijms20204994] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 10/04/2019] [Accepted: 10/07/2019] [Indexed: 12/11/2022] Open
Abstract
Cichlid fishes are the subject of scientific interest because of their rapid adaptive radiation, resulting in extensive ecological and taxonomic diversity. In this study, we examined 11 morphologically distinct cichlid species endemic to Barombi Mbo, the largest crater lake in western Cameroon, namely Konia eisentrauti, Konia dikume, Myaka myaka, Pungu maclareni, Sarotherodon steinbachi, Sarotherodon lohbergeri, Sarotherodon linnellii, Sarotherodon caroli, Stomatepia mariae, Stomatepia pindu, and Stomatepia mongo. These species supposedly evolved via sympatric ecological speciation from a common ancestor, which colonized the lake no earlier than one million years ago. Here we present the first comparative cytogenetic analysis of cichlid species from Barombi Mbo Lake using both conventional (Giemsa staining, C-banding, and CMA3/DAPI staining) and molecular (fluorescence in situ hybridization with telomeric, 5S, and 28S rDNA probes) methods. We observed stability on both macro and micro-chromosomal levels. The diploid chromosome number was 2n = 44, and the karyotype was invariably composed of three pairs of meta/submetacentric and 19 pairs of subtelo/acrocentric chromosomes in all analysed species, with the same numbers of rDNA clusters and distribution of heterochromatin. The results suggest the evolutionary stability of chromosomal set; therefore, the large-scale chromosomal rearrangements seem to be unlikely associated with the sympatric speciation in Barombi Mbo.
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Affiliation(s)
- Zuzana Majtánová
- Laboratory of Fish Genetics, Institute of Animal Physiology and Genetics, Czech Academy of Sciences, 27721 Liběchov, Czech Republic.
| | - Adrian Indermaur
- Zoological Institute, University of Basel, 4051 Basel, Switzerland.
| | - Arnold Roger Bitja Nyom
- Department of Biological Sciences, University of Ngaoundéré, Ngaoundéré P.O Box 454, Cameroon.
- Department of Management of Fisheries and Aquatic Ecosystems, University of Douala, Douala P.O Box 2701, Cameroon.
| | - Petr Ráb
- Laboratory of Fish Genetics, Institute of Animal Physiology and Genetics, Czech Academy of Sciences, 27721 Liběchov, Czech Republic.
| | - Zuzana Musilova
- Department of Zoology, Faculty of Science, Charles University in Prague, 12844 Prague, Czech Republic.
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22
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Musilova Z, Indermaur A, Bitja‐Nyom AR, Omelchenko D, Kłodawska M, Albergati L, Remišová K, Salzburger W. Evolution of the visual sensory system in cichlid fishes from crater lake Barombi Mbo in Cameroon. Mol Ecol 2019; 28:5010-5031. [DOI: 10.1111/mec.15217] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 08/09/2019] [Accepted: 08/13/2019] [Indexed: 01/09/2023]
Affiliation(s)
- Zuzana Musilova
- Department of Zoology Charles University in Prague Prague Czech Republic
- Zoological Institute University of Basel Basel Switzerland
| | | | - Arnold Roger Bitja‐Nyom
- Department of Biological Sciences University of Ngaoundéré Ngaoundéré Cameroon
- Department of Management of Fisheries and Aquatic Ecosystems University of Douala Douala Cameroon
| | - Dmytro Omelchenko
- Department of Zoology Charles University in Prague Prague Czech Republic
| | - Monika Kłodawska
- Department of Zoology Charles University in Prague Prague Czech Republic
| | - Lia Albergati
- Zoological Institute University of Basel Basel Switzerland
| | - Kateřina Remišová
- Department of Physiology Charles University in Prague Prague Czech Republic
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23
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Martin CH, McGirr JA, Richards EJ, St. John ME. How to Investigate the Origins of Novelty: Insights Gained from Genetic, Behavioral, and Fitness Perspectives. Integr Org Biol 2019; 1:obz018. [PMID: 33791533 PMCID: PMC7671130 DOI: 10.1093/iob/obz018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Biologists are drawn to the most extraordinary adaptations in the natural world, often referred to as evolutionary novelties, yet rarely do we understand the microevolutionary context underlying the origins of novel traits, behaviors, or ecological niches. Here we discuss insights gained into the origins of novelty from a research program spanning biological levels of organization from genotype to fitness in Caribbean pupfishes. We focus on a case study of the origins of novel trophic specialists on San Salvador Island, Bahamas and place this radiation in the context of other rapid radiations. We highlight questions that can be addressed about the origins of novelty at different biological levels, such as measuring the isolation of novel phenotypes on the fitness landscape, locating the spatial and temporal origins of adaptive variation contributing to novelty, detecting dysfunctional gene regulation due to adaptive divergence, and connecting behaviors with novel traits. Evolutionary novelties are rare, almost by definition, and we conclude that integrative case studies can provide insights into this rarity relative to the dynamics of adaptation to more common ecological niches and repeated parallel speciation, such as the relative isolation of novel phenotypes on fitness landscapes and the transient availability of ecological, genetic, and behavioral opportunities.
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Affiliation(s)
- C H Martin
- Department of Integrative Biology and Museum of Vertebrate Zoology, University of California, Berkeley, CA 94720, USA
| | - J A McGirr
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27514, USA
| | - E J Richards
- Department of Integrative Biology and Museum of Vertebrate Zoology, University of California, Berkeley, CA 94720, USA
| | - M E St. John
- Department of Integrative Biology and Museum of Vertebrate Zoology, University of California, Berkeley, CA 94720, USA
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24
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Richards EJ, Servedio MR, Martin CH. Searching for Sympatric Speciation in the Genomic Era. Bioessays 2019; 41:e1900047. [PMID: 31245871 PMCID: PMC8175013 DOI: 10.1002/bies.201900047] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 04/22/2019] [Indexed: 12/25/2022]
Abstract
Sympatric speciation illustrates how natural and sexual selection may create new species in isolation without geographic barriers. However, recent genomic reanalyses of classic examples of sympatric speciation reveal complex histories of secondary gene flow from outgroups into the radiation. In contrast, the rich theoretical literature on this process distinguishes among a diverse range of models based on simple genetic histories and different types of reproductive isolating barriers. Thus, there is a need to revisit how to connect theoretical models of sympatric speciation and their predictions to empirical case studies in the face of widespread gene flow. Here, theoretical differences among different types of sympatric speciation and speciation-with-gene-flow models are reviewed and summarized, and genomic analyses are proposed for distinguishing which models apply to case studies based on the timing and function of adaptive introgression. Investigating whether secondary gene flow contributed to reproductive isolation is necessary to test whether predictions of theory are ultimately borne out in nature.
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Affiliation(s)
- Emilie J. Richards
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill NC
| | - Maria R. Servedio
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill NC
| | - Christopher H. Martin
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill NC
- Integrative Biology and Museum of Vertebrate Zoology, University of California, Berkeley, CA
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25
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Taylor SA, Larson EL. Insights from genomes into the evolutionary importance and prevalence of hybridization in nature. Nat Ecol Evol 2019; 3:170-177. [DOI: 10.1038/s41559-018-0777-y] [Citation(s) in RCA: 211] [Impact Index Per Article: 42.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 12/04/2018] [Indexed: 01/27/2023]
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