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Funk ER, Spellman GM, Winker K, Withrow JJ, Ruegg KC, Zavaleta E, Taylor SA. Phylogenomic Data Reveal Widespread Introgression Across the Range of an Alpine and Arctic Specialist. Syst Biol 2020; 70:527-541. [PMID: 32941630 DOI: 10.1093/sysbio/syaa071] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 08/28/2020] [Accepted: 08/31/2020] [Indexed: 01/10/2023] Open
Abstract
Understanding how gene flow affects population divergence and speciation remains challenging. Differentiating one evolutionary process from another can be difficult because multiple processes can produce similar patterns, and more than one process can occur simultaneously. Although simple population models produce predictable results, how these processes balance in taxa with patchy distributions and complicated natural histories is less certain. These types of populations might be highly connected through migration (gene flow), but can experience stronger effects of genetic drift and inbreeding, or localized selection. Although different signals can be difficult to separate, the application of high-throughput sequence data can provide the resolution necessary to distinguish many of these processes. We present whole-genome sequence data for an avian species group with an alpine and arctic tundra distribution to examine the role that different population genetic processes have played in their evolutionary history. Rosy-finches inhabit high elevation mountaintop sky islands and high-latitude island and continental tundra. They exhibit extensive plumage variation coupled with low levels of genetic variation. Additionally, the number of species within the complex is debated, making them excellent for studying the forces involved in the process of diversification, as well as an important species group in which to investigate species boundaries. Total genomic variation suggests a broadly continuous pattern of allele frequency changes across the mainland taxa of this group in North America. However, phylogenomic analyses recover multiple distinct, well supported, groups that coincide with previously described morphological variation and current species-level taxonomy. Tests of introgression using D-statistics and approximate Bayesian computation reveal significant levels of introgression between multiple North American taxa. These results provide insight into the balance between divergent and homogenizing population genetic processes and highlight remaining challenges in interpreting conflict between different types of analytical approaches with whole-genome sequence data. [ABBA-BABA; approximate Bayesian computation; gene flow; phylogenomics; speciation; whole-genome sequencing.].
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Affiliation(s)
- Erik R Funk
- Department of Ecology and Evolutionary Biology, University of Colorado Boulder, 1900 Pleasant St. 334 UCB, Boulder, CO 80309, USA
| | - Garth M Spellman
- Department of Zoology, Denver Museum of Nature and Science, 2001 Colorado Blvd., Denver, CO 80205, USA
| | - Kevin Winker
- University of Alaska Museum, University of Alaska Fairbanks, 1962 Yukon Dr., Fairbanks, AK 99775, USA
| | - Jack J Withrow
- University of Alaska Museum, University of Alaska Fairbanks, 1962 Yukon Dr., Fairbanks, AK 99775, USA
| | - Kristen C Ruegg
- Department of Biology, Colorado State University, 251 W Pitkin St., Fort Collins, CO 80521, USA
| | - Erika Zavaleta
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, 1156 High St., Santa Cruz CA, 95064, USA
| | - Scott A Taylor
- Department of Ecology and Evolutionary Biology, University of Colorado Boulder, 1900 Pleasant St. 334 UCB, Boulder, CO 80309, USA
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52
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Chan KO, Hutter CR, Wood PL, Grismer LL, Das I, Brown RM. Gene flow creates a mirage of cryptic species in a Southeast Asian spotted stream frog complex. Mol Ecol 2020; 29:3970-3987. [PMID: 32808335 DOI: 10.1111/mec.15603] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Revised: 07/29/2020] [Accepted: 08/13/2020] [Indexed: 02/06/2023]
Abstract
Most new cryptic species are described using conventional tree- and distance-based species delimitation methods (SDMs), which rely on phylogenetic arrangements and measures of genetic divergence. However, although numerous factors such as population structure and gene flow are known to confound phylogenetic inference and species delimitation, the influence of these processes is not frequently evaluated. Using large numbers of exons, introns, and ultraconserved elements obtained using the FrogCap sequence-capture protocol, we compared conventional SDMs with more robust genomic analyses that assess population structure and gene flow to characterize species boundaries in a Southeast Asian frog complex (Pulchrana picturata). Our results showed that gene flow and introgression can produce phylogenetic patterns and levels of divergence that resemble distinct species (up to 10% divergence in mitochondrial DNA). Hybrid populations were inferred as independent (singleton) clades that were highly divergent from adjacent populations (7%-10%) and unusually similar (<3%) to allopatric populations. Such anomalous patterns are not uncommon in Southeast Asian amphibians, which brings into question whether the high levels of cryptic diversity observed in other amphibian groups reflect distinct cryptic species-or, instead, highly admixed and structured metapopulation lineages. Our results also provide an alternative explanation to the conundrum of divergent (sometimes nonsister) sympatric lineages-a pattern that has been celebrated as indicative of true cryptic speciation. Based on these findings, we recommend that species delimitation of continuously distributed "cryptic" groups should not rely solely on conventional SDMs, but should necessarily examine population structure and gene flow to avoid taxonomic inflation.
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Affiliation(s)
- Kin O Chan
- Lee Kong Chian National History Museum, Faculty of Science, National University of Singapore, Singapore
| | - Carl R Hutter
- Biodiversity Institute and Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS, USA.,Museum of Natural Sciences and Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, USA
| | - Perry L Wood
- Biodiversity Institute and Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS, USA.,Department of Biological Sciences & Museum of Natural History, Auburn University, Auburn, AL, USA
| | - L L Grismer
- Herpetology Laboratory, Department of Biology, La Sierra University, Riverside, CA, USA
| | - Indraneil Das
- Institute of Biodiversity and Environmental Conservation, Universiti Malaysia Sarawak, Kota Samarahan, Sarawak, Malaysia
| | - Rafe M Brown
- Biodiversity Institute and Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS, USA
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53
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Mays HL, Oehler DA, Morrison KW, Morales AE, Lycans A, Perdue J, Battley PF, Cherel Y, Chilvers BL, Crofts S, Demongin L, Fry WR, Hiscock J, Kusch A, Marin M, Poisbleau M, Quillfeldt P, Raya Rey A, Steinfurth A, Thompson DR, Weakley LA. Phylogeography, Population Structure, and Species Delimitation in Rockhopper Penguins (Eudyptes chrysocome and Eudyptes moseleyi). J Hered 2020; 110:801-817. [PMID: 31737899 DOI: 10.1093/jhered/esz051] [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: 08/15/2018] [Accepted: 08/10/2019] [Indexed: 01/05/2023] Open
Abstract
Rockhopper penguins are delimited as 2 species, the northern rockhopper (Eudyptes moseleyi) and the southern rockhopper (Eudyptes chrysocome), with the latter comprising 2 subspecies, the western rockhopper (Eudyptes chrysocome chrysocome) and the eastern rockhopper (Eudyptes chrysocome filholi). We conducted a phylogeographic study using multilocus data from 114 individuals sampled across 12 colonies from the entire range of the northern/southern rockhopper complex to assess potential population structure, gene flow, and species limits. Bayesian and likelihood methods with nuclear and mitochondrial DNA, including model testing and heuristic approaches, support E. moseleyi and E. chrysocome as distinct species lineages with a divergence time of 0.97 Ma. However, these analyses also indicated the presence of gene flow between these species. Among southern rockhopper subspecies, we found evidence of significant gene flow and heuristic approaches to species delimitation based on the genealogical diversity index failed to delimit them as species. The best-supported population models for the southern rockhoppers were those where E. c. chrysocome and E. c. filholi were combined into a single lineage or 2 lineages with bidirectional gene flow. Additionally, we found that E. c. filholi has the highest effective population size while E. c. chrysocome showed similar effective population size to that of the endangered E. moseleyi. We suggest that the current taxonomic definitions within rockhopper penguins be upheld and that E. chrysocome populations, all found south of the subtropical front, should be treated as a single taxon with distinct management units for E. c. chrysocome and E. c. filholi.
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Affiliation(s)
- Herman L Mays
- Department of Biological Sciences, Marshall University, Huntington, WV
| | - David A Oehler
- Wildlife Conservation Society, Bronx, NY.,Feather Link, Inc., Cincinnati, OH
| | | | - Ariadna E Morales
- Division of Vertebrate Zoology, American Museum of Natural History, New York, NY
| | - Alyssa Lycans
- Department of Biological Sciences, Marshall University, Huntington, WV
| | - Justin Perdue
- Department of Biological Sciences, Marshall University, Huntington, WV
| | - Phil F Battley
- School of Agriculture and Environment, Massey University, Palmerston North, New Zealand
| | - Yves Cherel
- Centre d'Etudes Biologiques de Chizé, UMR 7372 du CNRS-La Rochelle Université, Villiers-en-Bois, France
| | - B Louise Chilvers
- School of Veterinary Science, Massey University, Palmerston North, New Zealand
| | - Sarah Crofts
- Falklands Conservation, Stanley, Falkland Islands
| | | | | | - Jo Hiscock
- Department of Conservation, Invercargill, New Zealand
| | - Alejandro Kusch
- Wildlife Conservation Society, Bronx, NY.,Feather Link, Inc., Cincinnati, OH
| | - Manuel Marin
- Feather Link, Inc., Cincinnati, OH.,Section of Ornithology, Natural History Museum of Los Angeles County, Los Angeles, CA
| | - Maud Poisbleau
- Department of Biology, Behavioural Ecology and Ecophysiology Group, University of Antwerp, Antwerp (Wilrijk), Belgium
| | - Petra Quillfeldt
- Department of Animal Ecology & Systematics, Justus Liebig University Giessen, Giessen, Germany
| | - Andrea Raya Rey
- National Scientific and Technical Research Council, Austral Center for Scientific Investigation, Ushuaia, Argentina.,Institute of Polar Science, National University of Tierra del Fuego, Ushuaia, Argentina.,Wildlife Conservation Society, Buenos Aires, Argentina
| | - Antje Steinfurth
- FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Rondebosch, South Africa.,RSPB Centre for Conservation Science, Royal Society for the Protection of Birds, Cambridge, UK
| | - David R Thompson
- National Institute of Water and Atmospheric Research, Wellington, New Zealand
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54
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Perrier C, Rougemont Q, Charmantier A. Demographic history and genomics of local adaptation in blue tit populations. Evol Appl 2020; 13:1145-1165. [PMID: 32684952 PMCID: PMC7359843 DOI: 10.1111/eva.13035] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 05/11/2020] [Accepted: 05/18/2020] [Indexed: 12/24/2022] Open
Abstract
Understanding the genomic processes underlying local adaptation is a central aim of modern evolutionary biology. This task requires identifying footprints of local selection but also estimating spatio‐temporal variations in population demography and variations in recombination rate and in diversity along the genome. Here, we investigated these parameters in blue tit populations inhabiting deciduous versus evergreen forests, and insular versus mainland areas, in the context of a previously described strong phenotypic differentiation. Neighboring population pairs of deciduous and evergreen habitats were weakly genetically differentiated (FST = 0.003 on average), nevertheless with a statistically significant effect of habitat type on the overall genetic structure. This low differentiation was consistent with the strong and long‐lasting gene flow between populations inferred by demographic modeling. In turn, insular and mainland populations were moderately differentiated (FST = 0.08 on average), in line with the inference of moderate ancestral migration, followed by isolation since the end of the last glaciation. Effective population sizes were large, yet smaller on the island than on the mainland. Weak and nonparallel footprints of divergent selection between deciduous and evergreen populations were consistent with their high connectivity and the probable polygenic nature of local adaptation in these habitats. In turn, stronger footprints of divergent selection were identified between long isolated insular versus mainland birds and were more often found in regions of low recombination, as expected from theory. Lastly, we identified a genomic inversion on the mainland, spanning 2.8 Mb. These results provide insights into the demographic history and genetic architecture of local adaptation in blue tit populations at multiple geographic scales.
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Affiliation(s)
- Charles Perrier
- Centre d'Ecologie Fonctionnelle et Evolutive UMR 5175 CNRS Univ Montpellier CNRS EPHE IRD Univ Paul Valéry Montpellier 3 Montpellier France.,Centre de Biologie pour la Gestion des Populations UMR CBGP INRAE CIRAD IRD Montpellier SupAgro Univ Montpellier Montpellier France
| | - Quentin Rougemont
- Département de Biologie Institut de Biologie Intégrative et des Systèmes (IBIS) Université Laval Québec Québec Canada
| | - Anne Charmantier
- Centre d'Ecologie Fonctionnelle et Evolutive UMR 5175 CNRS Univ Montpellier CNRS EPHE IRD Univ Paul Valéry Montpellier 3 Montpellier France
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55
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56
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Marin J, Achaz G, Crombach A, Lambert A. The genomic view of diversification. J Evol Biol 2020; 33:1387-1404. [PMID: 32654283 DOI: 10.1111/jeb.13677] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 05/11/2020] [Accepted: 06/17/2020] [Indexed: 11/29/2022]
Abstract
The process of species diversification is traditionally summarized by a single tree, the species tree, whose reconstruction from molecular data is hindered by frequent conflicts between gene genealogies. Here, we argue that instead of seeing these conflicts as nuisances, we can exploit them to inform the diversification process itself. We adopt a gene-based view of diversification to model the ubiquitous presence of gene flow between diverging lineages, one of the most important processes explaining disagreements among gene trees. We propose a new framework for modelling the joint evolution of gene and species lineages relaxing the hierarchy between the species tree and gene trees inherent to the standard view, as embodied in a popular model known as the multispecies coalescent (MSC). We implement this framework in two alternative models called the gene-based diversification models (GBD): (a) GBD-forward following all evolving genomes through time and (b) GBD-backward based on coalescent theory. They feature four parameters tuning colonization, gene flow, genetic drift and genetic differentiation. We propose an inference method based on differences between gene trees. Applied to two empirical data sets prone to gene flow, we find better support for the GBD-backward model than for the MSC model. Along with the increasing awareness of the extent of gene flow, this work shows the importance of considering the richer signal contained in genomic histories, rather than in the mere species tree, to better apprehend the complex evolutionary history of species.
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Affiliation(s)
- Julie Marin
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, PSL Research University, Paris, France
| | - Guillaume Achaz
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, PSL Research University, Paris, France.,Institut de Systématique, Évolution, Biodiversité (ISYEB), MNHN, CNRS, EPHE, Sorbonne Université, Paris, France.,UMR 7206 Eco-anthropologie, Muséum National d'Histoire Naturelle, Centre National de la Recherche Scientifique, Université de Paris, Paris, France
| | - Anton Crombach
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, PSL Research University, Paris, France.,Inria, Lyon Antenne La Doua, Villeurbanne, France.,INSA-Lyon, LIRIS, UMR 5205, Université de Lyon, Villeurbanne, France
| | - Amaury Lambert
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, PSL Research University, Paris, France.,Laboratoire de Probabilités, Statistique et Modélisation (LPSM), CNRS UMR 8001, Sorbonne Université, Paris, France
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57
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Jiao X, Yang Z. Defining Species When There is Gene Flow. Syst Biol 2020; 70:108-119. [PMID: 32617579 DOI: 10.1093/sysbio/syaa052] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 06/23/2020] [Accepted: 06/23/2020] [Indexed: 12/20/2022] Open
Abstract
Whatever one's definition of species, it is generally expected that individuals of the same species should be genetically more similar to each other than they are to individuals of another species. Here, we show that in the presence of cross-species gene flow, this expectation may be incorrect. We use the multispecies coalescent model with continuous-time migration or episodic introgression to study the impact of gene flow on genetic differences within and between species and highlight a surprising but plausible scenario in which different population sizes and asymmetrical migration rates cause a genetic sequence to be on average more closely related to a sequence from another species than to a sequence from the same species. Our results highlight the extraordinary impact that even a small amount of gene flow may have on the genetic history of the species. We suggest that contrasting long-term migration rate and short-term hybridization rate, both of which can be estimated using genetic data, may be a powerful approach to detecting the presence of reproductive barriers and to define species boundaries.[Gene flow; introgression; migration; multispecies coalescent; species concept; species delimitation.].
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Affiliation(s)
- Xiyun Jiao
- Department of Genetics, Evolution and Environment, University College London, Gower Street, London WC1E 6BT, UK
| | - Ziheng Yang
- Department of Genetics, Evolution and Environment, University College London, Gower Street, London WC1E 6BT, UK
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58
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Jusoh WFA, Ballantyne L, Chan KO. DNA-based species delimitation reveals cryptic and incipient species in synchronous flashing fireflies (Coleoptera: Lampyridae) of Southeast Asia. Biol J Linn Soc Lond 2020. [DOI: 10.1093/biolinnean/blaa072] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Abstract
Synchronous flashing fireflies of the genus Pteroptyx are ubiquitous throughout Southeast Asia, yet fundamental knowledge about their biodiversity is lacking. Recent studies have revealed notable population-level phylogeographical structure within the Pteroptyx tener and P. bearni groups in Malaysia, suggesting that cryptic species may exist. Additionally, morphological and genetic similarities between P. balingiana and P. malaccae have raised questions about the former’s validity as a distinct species. We collected samples from previously unsampled populations and assembled the most comprehensive genetic dataset for Pteroptyx to date, to characterize species boundaries within the P. tener, P. bearni and P. malaccae groups. Using a suite of species delimitation analyses, we show that P. tener along the west coast of Peninsular Malaysia (PM) is distinct from populations from the east coast and Borneo despite the absence of morphological differentiation. However, analyses could not conclusively differentiate P. bearni from Borneo and eastern PM, nor identify P. balingiana and P. malaccae as distinct species, indicating that these populations may be conspecific or represent incipient species. This study underlines the need to increase geographical, taxonomic and genetic sampling of Southeast Asian fireflies to provide a better understanding of their biodiversity.
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Affiliation(s)
- Wan F A Jusoh
- Lee Kong Chian Natural History Museum, Faculty of Science, National University of Singapore, Singapore
| | - Lesley Ballantyne
- School of Agricultural and Wine Sciences, Charles Sturt University, Wagga Wagga, Australia
| | - Kin Onn Chan
- Lee Kong Chian Natural History Museum, Faculty of Science, National University of Singapore, Singapore
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59
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Tonzo V, Papadopoulou A, Ortego J. Genomic footprints of an old affair: Single nucleotide polymorphism data reveal historical hybridization and the subsequent evolution of reproductive barriers in two recently diverged grasshoppers with partly overlapping distributions. Mol Ecol 2020; 29:2254-2268. [DOI: 10.1111/mec.15475] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 05/10/2020] [Accepted: 05/11/2020] [Indexed: 12/17/2022]
Affiliation(s)
- Vanina Tonzo
- Department of Integrative Ecology Estación Biológica de Doñana (EBD‐CSIC) Seville Spain
| | - Anna Papadopoulou
- Department of Biological Sciences University of Cyprus Nicosia Cyprus
| | - Joaquín Ortego
- Department of Integrative Ecology Estación Biológica de Doñana (EBD‐CSIC) Seville Spain
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60
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Pilakouta N, Killen SS, Kristjánsson BK, Skúlason S, Lindström J, Metcalfe NB, Parsons KJ. Multigenerational exposure to elevated temperatures leads to a reduction in standard metabolic rate in the wild. Funct Ecol 2020; 34:1205-1214. [PMID: 32612318 PMCID: PMC7318562 DOI: 10.1111/1365-2435.13538] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 01/20/2020] [Indexed: 01/06/2023]
Abstract
In light of global climate change, there is a pressing need to understand and predict the capacity of populations to respond to rising temperatures. Metabolic rate is a key trait that is likely to influence the ability to cope with climate change. Yet, empirical and theoretical work on metabolic rate responses to temperature changes has so far produced mixed results and conflicting predictions.Our study addresses this issue using a novel approach of comparing fish populations in geothermally warmed lakes and adjacent ambient-temperature lakes in Iceland. This unique 'natural experiment' provides repeated and independent examples of populations experiencing contrasting thermal environments for many generations over a small geographic scale, thereby avoiding the confounding factors associated with latitudinal or elevational comparisons. Using Icelandic sticklebacks from three warm and three cold habitats, we measured individual metabolic rates across a range of acclimation temperatures to obtain reaction norms for each population.We found a general pattern for a lower standard metabolic rate (SMR) in sticklebacks from warm habitats when measured at a common temperature, as predicted by Krogh's rule. Metabolic rate differences between warm- and cold-habitat sticklebacks were more pronounced at more extreme acclimation temperatures, suggesting the release of cryptic genetic variation upon exposure to novel conditions, which can reveal hidden evolutionary potential. We also found a stronger divergence in metabolic rate between thermal habitats in allopatry than sympatry, indicating that gene flow may constrain physiological adaptation when dispersal between warm and cold habitats is possible.In sum, our study suggests that fish may diverge toward a lower SMR in a warming world, but this might depend on connectivity and gene flow between different thermal habitats. A free Plain Language Summary can be found within the Supporting Information of this article.
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Affiliation(s)
- Natalie Pilakouta
- Institute of Biodiversity, Animal Health, and Comparative MedicineUniversity of GlasgowGlasgowUK
- School of Biological SciencesUniversity of AberdeenAberdeenUK
| | - Shaun S. Killen
- Institute of Biodiversity, Animal Health, and Comparative MedicineUniversity of GlasgowGlasgowUK
| | | | - Skúli Skúlason
- Department of Aquaculture and Fish BiologyHólar UniversitySauðárkrókurIceland
- Icelandic Museum of Natural HistoryReykjavíkIceland
| | - Jan Lindström
- Institute of Biodiversity, Animal Health, and Comparative MedicineUniversity of GlasgowGlasgowUK
| | - Neil B. Metcalfe
- Institute of Biodiversity, Animal Health, and Comparative MedicineUniversity of GlasgowGlasgowUK
| | - Kevin J. Parsons
- Institute of Biodiversity, Animal Health, and Comparative MedicineUniversity of GlasgowGlasgowUK
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61
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Sun SJ, Catherall AM, Pascoal S, Jarrett BJM, Miller SE, Sheehan MJ, Kilner RM. Rapid local adaptation linked with phenotypic plasticity. Evol Lett 2020; 4:345-359. [PMID: 32774883 PMCID: PMC7403679 DOI: 10.1002/evl3.176] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 04/12/2020] [Accepted: 04/29/2020] [Indexed: 11/05/2022] Open
Abstract
Models of "plasticity-first" evolution are attractive because they explain the rapid evolution of new complex adaptations. Nevertheless, it is unclear whether plasticity can facilitate rapid microevolutionary change between diverging populations. Here, we show how plasticity may have generated adaptive differences in fecundity between neighboring wild populations of burying beetles Nicrophorus vespilloides. These populations occupy distinct Cambridgeshire woodlands that are just 2.5 km apart and that probably originated from a common ancestral population about 1000-4000 years ago. We find that populations are divergently adapted to breed on differently sized carrion. Adaptive differences in clutch size and egg size are associated with divergence at loci connected with oogenesis. The populations differ specifically in the elevation of the reaction norm linking clutch size to carrion size (i.e., genetic accommodation), and in the likelihood that surplus offspring will be lost after hatching. We suggest that these two processes may have facilitated rapid local adaptation on a fine-grained spatial scale.
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Affiliation(s)
- Syuan-Jyun Sun
- Department of Zoology University of Cambridge Cambridge CB2 3EJ United Kingdom
| | - Andrew M Catherall
- Department of Zoology University of Cambridge Cambridge CB2 3EJ United Kingdom
| | - Sonia Pascoal
- Department of Zoology University of Cambridge Cambridge CB2 3EJ United Kingdom
| | - Benjamin J M Jarrett
- Department of Zoology University of Cambridge Cambridge CB2 3EJ United Kingdom.,Department of Entomology Michigan State University East Lansing Michigan 48824
| | - Sara E Miller
- Department of Neurobiology and Behavior Cornell University Ithaca New York 14853
| | - Michael J Sheehan
- Department of Neurobiology and Behavior Cornell University Ithaca New York 14853
| | - Rebecca M Kilner
- Department of Zoology University of Cambridge Cambridge CB2 3EJ United Kingdom
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62
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Everson KM, Goodman SM, Olson LE. Speciation and gene flow in two sympatric small mammals from Madagascar, Microgale fotsifotsy and M. soricoides (Mammalia: Tenrecidae). Mol Ecol 2020; 29:1717-1729. [PMID: 32270561 DOI: 10.1111/mec.15433] [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: 08/09/2019] [Revised: 03/13/2020] [Accepted: 03/27/2020] [Indexed: 11/28/2022]
Abstract
Madagascar's shrew tenrecs (Mammalia: Tenrecidae; Microgale, Nesogale) represent an excellent system for studying speciation. Most species are endemic to the island's eastern humid forests, a region renowned for high levels of biodiversity and a high rate of in situ diversification. We set out to understand the speciation dynamics in a clade of recently described taxa: Microgale fotsifotsy and M. soricoides, which have nearly identical distributions in the moist evergreen forest, and M. nasoloi, which occurs in the western dry deciduous forest. A phylogenetic analysis using mitochondrial DNA data recovered two distinct clades of M. fotsifotsy: a south clade that is sister to, and broadly sympatric with, M. soricoides, and a north clade that is sister to the dry-forest and distantly allopatric species M. nasoloi. To better understand this result, we analysed cranioskeletal measurements and performed demographic analyses using nuclear sequence data from ultraconserved elements. Nuclear data did not support a sister relationship between M. soricoides and the south clade of M. fotsifotsy but did demonstrate introgression between these clades, which probably explains the discordance between nuclear and mitochondrial phylogenies. Demographic analyses also revealed the absence of gene flow between the north and south clades of M. fotsifotsy. Morphometric data revealed several major differences between M. soricoides and M. fotsifotsy, as well as more subtle differences between the two clades of M. fotsifotsy. In light of these results, we treat the south clade of M. fotsifotsy as a new candidate species. Our findings demonstrate the utility of integrating multiple data types to understand complex speciation histories, and contribute to a growing body of evidence that species diversity on Madagascar is underestimated.
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Affiliation(s)
- Kathryn M Everson
- University of Alaska Museum, Fairbanks, AK, USA.,Biology Department, University of Kentucky, Lexington, KY, USA
| | - Steven M Goodman
- Field Museum of Natural History, Chicago, IL, USA.,Association Vahatra, Antananarivo, Madagascar
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63
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Sotelo G, Duvetorp M, Costa D, Panova M, Johannesson K, Faria R. Phylogeographic history of flat periwinkles, Littorina fabalis and L. obtusata. BMC Evol Biol 2020; 20:23. [PMID: 32039690 PMCID: PMC7011314 DOI: 10.1186/s12862-019-1561-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 12/12/2019] [Indexed: 12/15/2022] Open
Abstract
Background The flat periwinkles, Littorina fabalis and L. obtusata, are two sister species widely distributed throughout the Northern Atlantic shores with high potential to inform us about the process of ecological speciation in the intertidal. However, whether gene flow has occurred during their divergence is still a matter of debate. A comprehensive assessment of the genetic diversity of these species is also lacking and their main glacial refugia and dispersal barriers remain largely unknown. In order to fill these gaps, we sequenced two mitochondrial genes and two nuclear fragments to perform a phylogeographic analysis of flat periwinkles across their distribution range. Results We identified two main clades largely composed by species-specific haplotypes corresponding to L. obtusata and L. fabalis, with moderate to strong support, respectively. Importantly, a model of divergence with gene flow between the two species (from L. obtusata to L. fabalis) was better supported, both in Iberia and in northern-central Europe. Three mitochondrial clades were detected within L. fabalis and two within L. obtusata, with strong divergence between Iberia and the remaining populations. The largest component of the genetic variance within each species was explained by differences between geographic regions associated with these clades. Our data suggests that overall intraspecific genetic diversity is similar between the two flat periwinkle species and that populations from Iberia tend to be less diverse than populations from northern-central Europe. Conclusions The phylogeographic analysis of this sister-species pair supports divergence with gene flow. This system thus provides us with the opportunity to study the contribution of gene flow and natural selection during diversification. The distribution of the different clades suggests the existence of glacial refugia in Iberia and northern-central Europe for both species, with a main phylogeographic break between these regions. Although the genetic diversity results are not fully conclusive, the lower diversity observed in Iberia could reflect marginal conditions at the southern limit of their distribution range during the current interglacial period.
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Affiliation(s)
- Graciela Sotelo
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO, Laboratório Associado, Universidade do Porto, Vairão, Portugal.,Department of Animal and Plant Sciences, University of Sheffield, Sheffield, S10 2TN, UK
| | - Mårten Duvetorp
- Department of Marine Sciences, Tjärnö, University of Gothenburg, Strömstad, Sweden
| | - Diana Costa
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO, Laboratório Associado, Universidade do Porto, Vairão, Portugal
| | - Marina Panova
- Department of Marine Sciences, Tjärnö, University of Gothenburg, Strömstad, Sweden
| | - Kerstin Johannesson
- Department of Marine Sciences, Tjärnö, University of Gothenburg, Strömstad, Sweden
| | - Rui Faria
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO, Laboratório Associado, Universidade do Porto, Vairão, Portugal. .,Department of Animal and Plant Sciences, University of Sheffield, Sheffield, S10 2TN, UK. .,IBE, Institute of Evolutionary Biology (CSIC-UPF), Department of Experimental and Health Sciences, Pompeu Fabra University, Barcelona, Spain.
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64
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Costa D, Sotelo G, Kaliontzopoulou A, Carvalho J, Butlin R, Hollander J, Faria R. Hybridization patterns between two marine snails, Littorina fabalis and L. obtusata. Ecol Evol 2020; 10:1158-1179. [PMID: 32076505 PMCID: PMC7029087 DOI: 10.1002/ece3.5943] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 11/21/2019] [Accepted: 11/27/2019] [Indexed: 01/22/2023] Open
Abstract
Characterizing the patterns of hybridization between closely related species is crucial to understand the role of gene flow in speciation. In particular, systems comprising multiple contacts between sister species offer an outstanding opportunity to investigate how reproductive isolation varies with environmental conditions, demography and geographic contexts of divergence. The flat periwinkles, Littorina obtusata and L. fabalis (Gastropoda), are two intertidal sister species with marked ecological differences compatible with late stages of speciation. Although hybridization between the two was previously suggested, its extent across the Atlantic shores of Europe remained largely unknown. Here, we combined genetic (microsatellites and mtDNA) and morphological data (shell and male genital morphology) from multiple populations of flat periwinkles in north-western Iberia to assess the extent of current and past hybridization between L. obtusata and L. fabalis under two contrasting geographic settings of divergence (sympatry and allopatry). Hybridization signatures based on both mtDNA and microsatellites were stronger in sympatric sites, although evidence for recent extensive admixture was found in a single location. Misidentification of individuals into species based on shell morphology was higher in sympatric than in allopatric sites. However, despite hybridization, species distinctiveness based on this phenotypic trait together with male genital morphology remained relatively high. The observed variation in the extent of hybridization among locations provides a rare opportunity for future studies on the consequences of different levels of gene flow for reinforcement, thus informing about the mechanisms underlying the completion of speciation.
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Affiliation(s)
- Diana Costa
- CIBIO‐InBIOCentro de Investigação em Biodiversidade e Recursos GenéticosUniversidade do PortoVairãoPortugal
- Department of BiologyFaculty of SciencesUniversity of PortoPortoPortugal
- CIIMARInterdisciplinary Centre of Marine and Environmental ResearchUniversity of PortoPortoPortugal
| | - Graciela Sotelo
- CIBIO‐InBIOCentro de Investigação em Biodiversidade e Recursos GenéticosUniversidade do PortoVairãoPortugal
| | - Antigoni Kaliontzopoulou
- CIBIO‐InBIOCentro de Investigação em Biodiversidade e Recursos GenéticosUniversidade do PortoVairãoPortugal
| | - João Carvalho
- CIBIO‐InBIOCentro de Investigação em Biodiversidade e Recursos GenéticosUniversidade do PortoVairãoPortugal
- cE3cCentre for Ecology, Evolution and Environmental ChangesDepartamento de Biologia AnimalFaculdade de Ciências da Universidade de LisboaLisbonPortugal
| | - Roger Butlin
- Department of Animal and Plant SciencesUniversity of SheffieldSheffieldUK
- Department of Marine SciencesUniversity of GothenburgGothenburgSweden
| | - Johan Hollander
- Department of BiologyAquatic Ecology UnitLund UniversityLundSweden
- Global Ocean InstituteWorld Maritime UniversityMalmöSweden
| | - Rui Faria
- CIBIO‐InBIOCentro de Investigação em Biodiversidade e Recursos GenéticosUniversidade do PortoVairãoPortugal
- CIIMARInterdisciplinary Centre of Marine and Environmental ResearchUniversity of PortoPortoPortugal
- Department of Animal and Plant SciencesUniversity of SheffieldSheffieldUK
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65
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Abstract
Interspecific hybridization is the process where closely related species mate and produce offspring with admixed genomes. The genomic revolution has shown that hybridization is common, and that it may represent an important source of novel variation. Although most interspecific hybrids are sterile or less fit than their parents, some may survive and reproduce, enabling the transfer of adaptive variants across the species boundary, and even result in the formation of novel evolutionary lineages. There are two main variants of hybrid species genomes: allopolyploid, which have one full chromosome set from each parent species, and homoploid, which are a mosaic of the parent species genomes with no increase in chromosome number. The establishment of hybrid species requires the development of reproductive isolation against parental species. Allopolyploid species often have strong intrinsic reproductive barriers due to differences in chromosome number, and homoploid hybrids can become reproductively isolated from the parent species through assortment of genetic incompatibilities. However, both types of hybrids can become further reproductively isolated, gaining extrinsic isolation barriers, by exploiting novel ecological niches, relative to their parents. Hybrids represent the merging of divergent genomes and thus face problems arising from incompatible combinations of genes. Thus hybrid genomes are highly dynamic and undergo rapid evolutionary change, including genome stabilization in which selection against incompatible combinations results in fixation of compatible ancestry block combinations within the hybrid species. The potential for rapid adaptation or speciation makes hybrid genomes a particularly exciting subject of in evolutionary biology. Here we summarize how introgressed alleles or hybrid species can establish and how the resulting hybrid genomes evolve.
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Affiliation(s)
- Anna Runemark
- Department of Biology, Lund University, Lund, Sweden
- * E-mail:
| | - Mario Vallejo-Marin
- Biological and Environmental Sciences, University of Stirling, Stirling, Scotland, United Kingdom
| | - Joana I. Meier
- St John's College, Cambridge, Cambridge, United Kingdom
- Department of Zoology, University of Cambridge, Cambridge, United Kingdom
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66
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Forcina G, Guerrini M, Panayides P, Hadjigerou P, Khan AA, Barbanera F. Molecular taxonomy and intra-Palaearctic boundary: new insights from the biogeography of the black francolin (Francolinus francolinus) by means of microsatellite DNA. SYST BIODIVERS 2019. [DOI: 10.1080/14772000.2019.1691673] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Giovanni Forcina
- CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, Campus Agrário de Vairão, Vairão, 4485-661, Portugal
- Department of Biology, University of Pisa, Via A. Volta 4, Pisa, I-56126, Italy
| | - Monica Guerrini
- Department of Biology, University of Pisa, Via A. Volta 4, Pisa, I-56126, Italy
| | - Panicos Panayides
- Game & Fauna Service, Ministry of Interior, Nicosia, CY-1453, Cyprus
| | | | - Aleem Ahmed Khan
- Institute of Pure & Applied Biology, Zoology Division, Bahauddin Zakariya University, Multan, 60800, Pakistan
| | - Filippo Barbanera
- Department of Biology, University of Pisa, Via A. Volta 4, Pisa, I-56126, Italy
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67
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Semenov GA, Safran RJ, Smith CC, Turbek SP, Mullen SP, Flaxman SM. Unifying Theoretical and Empirical Perspectives on Genomic Differentiation. Trends Ecol Evol 2019; 34:987-995. [DOI: 10.1016/j.tree.2019.07.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 07/10/2019] [Accepted: 07/15/2019] [Indexed: 01/17/2023]
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68
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Hey J, Wang K. The effect of undetected recombination on genealogy sampling and inference under an isolation-with-migration model. Mol Ecol Resour 2019; 19:1593-1609. [PMID: 31479562 DOI: 10.1111/1755-0998.13083] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 07/22/2019] [Accepted: 07/24/2019] [Indexed: 11/30/2022]
Abstract
Many methods for fitting demographic models to data sets of aligned sequences rely upon an assumption that the data have a branching coalescent history without recombination within regions or loci. To mitigate the effects of the failure of this assumption, a common approach is to filter data and sample regions that pass the four-gamete criterion for recombination, an approach that allows data to run, but that is expected to detect only a minority of recombination events. A series of empirical tests of this approach were conducted using computer simulations with and without recombination for a variety of isolation-with-migration (IM) model for two and three populations. Only the IMa3 program was used, but the general results should apply to related genealogy-sampling-based methods for IM models or subsets of IM models. It was found that the details of sampling intervals that pass a four-gamete filter have a moderate effect, and that schemes that use the longest intervals, or that use overlapping intervals, gave poorer results. A simple approach of using a random nonoverlapping interval returned the smallest difference between results with and without recombination, with the mean difference between parameter estimates usually less than 20% of the true value (usually much less). However, the posterior probability distributions for migration rates were flatter with recombination, suggesting that filtering based on the four-gamete criterion, while necessary for methods like these, leads to reduced resolution on migration. A distinct, alternative approach, of using a finite sites mutation model and not filtering the data, performed quite poorly.
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Affiliation(s)
- Jody Hey
- Center for Computational Genetics and Genomics, Department of Biology, Temple University, Philadelphia, PA, USA
| | - Katherine Wang
- Center for Computational Genetics and Genomics, Department of Biology, Temple University, Philadelphia, PA, USA
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69
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Papadopulos AST, Igea J, Smith TP, Hutton I, Baker WJ, Butlin RK, Savolainen V. Ecological speciation in sympatric palms: 4. Demographic analyses support speciation of
Howea
in the face of high gene flow. Evolution 2019; 73:1996-2002. [DOI: 10.1111/evo.13813] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 07/04/2019] [Accepted: 07/16/2019] [Indexed: 12/11/2022]
Affiliation(s)
- Alexander S. T. Papadopulos
- Department of Life SciencesSilwood Park CampusImperial College London Ascot SL5 7PY United Kingdom
- Molecular Ecology and Fisheries Genetics LaboratoryEnvironment Centre WalesSchool of Natural SciencesBangor University Bangor LL57 2UW United Kingdom
| | - Javier Igea
- Department of Life SciencesSilwood Park CampusImperial College London Ascot SL5 7PY United Kingdom
- Department of Plant SciencesUniversity of Cambridge Cambridge CB2 3EA United Kingdom
| | - Thomas P. Smith
- Department of Life SciencesSilwood Park CampusImperial College London Ascot SL5 7PY United Kingdom
| | - Ian Hutton
- Lord Howe Island Museum Lord Howe Island New South Wales Australia
| | | | - Roger K. Butlin
- Department of Animal and Plant SciencesUniversity of Sheffield Sheffield S10 2TN United Kingdom
- Department of Marine SciencesUniversity of Gothenburg Gothenburg SE‐405 30 Sweden
| | - Vincent Savolainen
- Department of Life SciencesSilwood Park CampusImperial College London Ascot SL5 7PY United Kingdom
- Royal Botanic Gardens, Kew Richmond TW9 3AB United Kingdom
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70
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Toby Pennington R, Lavin M. Dispersal, isolation and diversification with continued gene flow in an Andean tropical dry forest. Mol Ecol 2019. [PMID: 28632343 DOI: 10.1111/mec.14182] [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] [Indexed: 11/26/2022]
Abstract
The Andes are the world's longest mountain chain, and the tropical Andes are the world's richest biodiversity hot spot. The origin of the tropical Andean cordillera is relatively recent because the elevation of the mountains was relatively low (400-2500 m palaeoelevations) only 10 MYA with final uplift being rapid. These final phases of the Andean orogeny are thought to have had a fundamental role in shaping processes of biotic diversification and biogeography, with these effects reaching far from the mountains themselves by changing the course of rivers and deposition of mineral-rich Andean sediments across the massive Amazon basin. In a recent issue of Molecular Ecology, Oswald, Overcast, Mauck, Andersen, and Smith (2017) investigate the biogeography and diversification of bird species in the Andes of Peru and Ecuador. Their study is novel in its focus on tropical dry forests (Figure 1) rather than more mesic biomes such as rain forests, cloud forests and paramos, which tend to be the focus of science and conservation in the Andean hot spot. It is also able to draw powerful conclusions via the first deployment of genomic approaches to a biogeographic question in the threatened dry forests of the New World.
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Affiliation(s)
| | - Matt Lavin
- Department of Plant Sciences & Plant Pathology, Montana State University, Bozeman, MT, USA
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71
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Krohn AR, Diepeveen ET, Bi K, Rosenblum EB. Local adaptation does not lead to genome-wide differentiation in lava flow lizards. Ecol Evol 2019; 9:6810-6820. [PMID: 31380017 PMCID: PMC6662252 DOI: 10.1002/ece3.5231] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2018] [Revised: 04/11/2019] [Accepted: 04/15/2019] [Indexed: 11/09/2022] Open
Abstract
Adaptation can occur with or without genome-wide differentiation. If adaptive loci are linked to traits involved in reproductive isolation, genome-wide divergence is likely, and speciation is possible. However, adaptation can also lead to phenotypic differentiation without genome-wide divergence if levels of ongoing gene flow are high. Here, we use the replicated occurrence of melanism in lava flow lizards to assess the relationship between local adaptation and genome-wide differentiation. We compare patterns of phenotypic and genomic divergence among lava flow and nonlava populations for three lizard species and three lava flows in the Chihuahuan Desert. We find that local phenotypic adaptation (melanism) is not typically accompanied by genome-wide differentiation. Specifically, lava populations do not generally exhibit greater divergence from nonlava populations than expected by geography alone, regardless of whether the lava formation is 5,000 or 760,000 years old. We also infer that gene flow between lava and nonlava populations is ongoing in all lava populations surveyed. Recent work in the isolation by environment and ecological speciation literature suggests that environmentally driven genome-wide differentiation is common in nature. However, local adaptation may often simply be local adaptation rather than an early stage of ecological speciation.
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Affiliation(s)
- Alexander R. Krohn
- Department of Environmental Science, Policy and ManagementUniversity of California, BerkeleyBerkeleyCalifornia
- Museum of Vertebrate ZoologyUniversity of California, BerkeleyBerkeleyCalifornia
| | - Eveline T. Diepeveen
- Department of Bionanoscience, Kavli Institute of NanoScience, Faculty of Applied SciencesDelft University of TechnologyDelftThe Netherlands
| | - Ke Bi
- Museum of Vertebrate ZoologyUniversity of California, BerkeleyBerkeleyCalifornia
- Computational Genomics Resource Laboratory (CGRL), California Institute for Quantitative Biosciences (QB3)University of California, BerkeleyBerkeleyCalifornia
| | - Erica Bree Rosenblum
- Department of Environmental Science, Policy and ManagementUniversity of California, BerkeleyBerkeleyCalifornia
- Museum of Vertebrate ZoologyUniversity of California, BerkeleyBerkeleyCalifornia
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72
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Chan KO, Grismer LL. To split or not to split? Multilocus phylogeny and molecular species delimitation of southeast Asian toads (family: Bufonidae). BMC Evol Biol 2019; 19:95. [PMID: 31023232 PMCID: PMC6485082 DOI: 10.1186/s12862-019-1422-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 04/12/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Recent studies have demonstrated that Bayesian species delimitation based on the multispecies coalescent model can produce inaccurate results by misinterpreting population splits as species divergences. An approach based on the genealogical divergence index (gdi) was shown to be a viable alternative, especially for delimiting allopatric populations where gene flow is low. We implemented these analyses to assess species boundaries in Southeast Asian toads, a group that is understudied and characterized by numerous unresolved species complexes. RESULTS Multilocus phylogenetic analyses showed that deep evolutionary relationships including the genera Sigalegalephrynus, Ghatophryne, Parapelophryne, Leptophryne, Pseudobufo, Rentapia, and Phrynoides remain unresolved. Comparison of genetic divergences revealed that intraspecific divergences among allopatric populations of Pelophyrne signata (Borneo vs. Peninsular Malaysia), Ingerophrynus parvus (Peninsular Malaysia vs. Myanmar), and Leptophryne borbonica (Peninsular Malaysia, Java, Borneo, and Sumatra) are consistent with interspecific divergences of other Southeast Asian bufonid taxa. Conversely, interspecific divergences between Pelophryne guentheri/P. api, Ansonia latiffi/A. leptopus, and I. gollum/I. divergens were low (< 3%) and consistent with intraspecific divergences of other closely related taxa. The BPP analysis produced variable results depending on prior settings and priors estimated from empirical data produced the best results that were also congruent with the gdi analysis. CONCLUSIONS This study showed that the evolutionary history of Southeast Asian toads is difficult to resolve and numerous relationships remain ambiguous. Although some results from the species delimitation analyses were inconclusive, they were nevertheless efficacious at identifying potential new species and taxonomic incompatibilities for future in-depth investigation. We also demonstrated the sensitivity of BPP to different priors and that careful selection priors based on empirical data can greatly improve the analysis. Finally, the gdi can be a robust tool to complement other species delimitation methods.
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Affiliation(s)
- Kin Onn Chan
- Lee Kong Chian Natural History Museum, National University of Singapore, 2 Conservatory Drive, Singapore, 117377 Singapore
| | - L. Lee Grismer
- Herpetology Laboratory, Department of Biology, La Sierra University, 4500 Riverwalk Parkway, Riverside, CA 92515 USA
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73
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Zarza E, Reynoso VH, Faria CMA, Emerson BC. Introgressive hybridization in a Spiny-Tailed Iguana, Ctenosaura pectinata, and its implications for taxonomy and conservation. PeerJ 2019; 7:e6744. [PMID: 31065455 PMCID: PMC6485205 DOI: 10.7717/peerj.6744] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Accepted: 03/05/2019] [Indexed: 11/30/2022] Open
Abstract
Introgression, the transmission of genetic material of one taxon into another through hybridization, can have various evolutionary outcomes. Previous studies have detected signs of introgression between western populations of the Mexican endemic and threatened spiny-tailed iguana, Ctenosaura pectinata. However, the extent of this phenomenon along the geographic distribution of the species is unknown. Here, we use multilocus data together with detailed geographic sampling to (1) define genotypic clusters within C. pectinata; (2) evaluate geographic concordance between maternally and biparentally inherited markers; (3) examine levels of introgression between genotypic clusters, and (4) suggest taxonomic modifications in light of this information. Applying clustering methods to genotypes of 341 individuals from 49 localities of C. pectinata and the closely related C. acanthura, we inferred the existence of five genotypic clusters. Contact zones between genotypic clusters with signatures of interbreeding were detected, showing different levels of geographic discordance with mtDNA lineages. In northern localities, mtDNA and microsatellites exhibit concordant distributions, supporting the resurrection of C. brachylopha. Similar concordance is observed along the distribution of C. acanthura, confirming its unique taxonomic identity. Genetic and geographic concordance is also observed for populations within southwestern Mexico, where the recognition of a new species awaits in depth taxonomic revision. In contrast, in western localities a striking pattern of discordance was detected where up to six mtDNA lineages co-occur with only two genotypic clusters. Given that the type specimen originated from this area, we suggest that individuals from western Mexico keep the name C. pectinata. Our results have profound implications for conservation, management, and forensics of Mexican iguanas.
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Affiliation(s)
- Eugenia Zarza
- Departamento de Zoología, Instituto de Biología, Universidad Nacional Autónoma de México, Ciudad de México, Mexico.,Grupo Académico de Biotecnología Ambiental, El Colegio de la Frontera Sur, Unidad Tapachula, Tapachula, Chiapas, Mexico.,CONACYT, Ciudad de México, Mexico
| | - Víctor H Reynoso
- Departamento de Zoología, Instituto de Biología, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Christiana M A Faria
- School of Biological Sciences, University of East Anglia, Norwich, UK.,Current Affiliation: Departamento de Biologia, Universidade Federal do Ceará, Campus do Pici, Fortaleza, Ceará, Brasil
| | - Brent C Emerson
- Island Ecology and Evolution Research Group, Instituto de Productos Naturales y Agrobiología (IPNA-CSIC), C/Astrofísico Francisco Sánchez 3, La Laguna, Tenerife, Canary Islands, Spain
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74
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Sobel JM, Stankowski S, Streisfeld MA. Variation in ecophysiological traits might contribute to ecogeographic isolation and divergence between parapatric ecotypes of
Mimulus aurantiacus. J Evol Biol 2019; 32:604-618. [DOI: 10.1111/jeb.13442] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Revised: 03/06/2019] [Accepted: 03/11/2019] [Indexed: 12/11/2022]
Affiliation(s)
- James M. Sobel
- Department of Biological Sciences Binghamton University (SUNY) Binghamton New York
| | - Sean Stankowski
- Institute of Ecology and Evolution University of Oregon Eugene Oregon
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75
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Blankers T, Berdan EL, Hennig RM, Mayer F. Physical linkage and mate preference generate linkage disequilibrium for behavioral isolation in two parapatric crickets. Evolution 2019; 73:777-791. [PMID: 30820950 PMCID: PMC6593781 DOI: 10.1111/evo.13706] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 02/04/2019] [Indexed: 12/23/2022]
Abstract
Behavioral isolation is a potent barrier to gene flow and a source of striking diversity in the animal kingdom. However, it remains unclear if the linkage disequilibrium (LD) between sex‐specific traits required for behavioral isolation results mostly from physical linkage between signal and preference loci or from directional mate preferences. Here, we test this in the field crickets Gryllus rubens and G. texensis. These closely related species diverged with gene flow and have strongly differentiated songs and preference functions for the mate calling song rhythm. We map quantitative trait loci for signal and preference traits (pQTL) as well as for gene expression associated with these traits (eQTL). We find strong, positive genetic covariance between song traits and between song and preference. Our results show that this is in part explained by incomplete physical linkage: although both linked pQTL and eQTL couple male and female traits, major effect loci for different traits were never on the same chromosome. We suggest that the finely tuned, highly divergent preference functions are likely an additional source of LD between male and female traits in this system. Furthermore, pleiotropy of gene expression presents an underappreciated mechanism to link sexually dimorphic phenotypes.
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Affiliation(s)
- Thomas Blankers
- Department of Behavioral Physiology, Humboldt-Universität zu Berlin, Berlin, Germany.,Leibniz Institute for Evolution and Biodiversity Science, Museum für Naturkunde Berlin, Berlin, Germany.,Current address: Department of Evolutionary and Population Biology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, The Netherlands
| | - Emma L Berdan
- Leibniz Institute for Evolution and Biodiversity Science, Museum für Naturkunde Berlin, Berlin, Germany.,Current address: Department of Marine Sciences, University of Gothenburg, Gothenburg, Sweden
| | - R Matthias Hennig
- Department of Behavioral Physiology, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Frieder Mayer
- Leibniz Institute for Evolution and Biodiversity Science, Museum für Naturkunde Berlin, Berlin, Germany.,Berlin-Brandenburg Institute of Advanced Biodiversity Research (BBIB), Berlin, Germany
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76
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Skeels A, Cardillo M. Reconstructing the Geography of Speciation from Contemporary Biodiversity Data. Am Nat 2019; 193:240-255. [DOI: 10.1086/701125] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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77
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Renza-Millán M, Lasso CA, Morales-Betancourt MA, Villa F, Caballero S. Mitochondrial DNA diversity and population structure of the ocellate freshwater stingray Potamotrygon motoro (Müller & Henle, 1841) (Myliobatiformes: Potamotrygonidae) in the Colombian Amazon and Orinoco Basins. Mitochondrial DNA A DNA Mapp Seq Anal 2019; 30:466-473. [DOI: 10.1080/24701394.2018.1546300] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Mariana Renza-Millán
- Laboratorio de Ecología Molecular de Vertebrados Acuáticos (LEMVA), Departamento de Ciencias Biológicas, Universidad de los Andes, Bogotá, Colombia
- Grupo de Investigación de Zoología, Departamento de Biología, Facultad de Ciencias, Universidad del Tolima, Ibagué, Colombia
| | - Carlos A. Lasso
- Instituto de Investigación de Recursos Biológicos Alexander Von Humboldt, Bogotá, Colombia
| | | | - Francisco Villa
- Grupo de Investigación de Zoología, Departamento de Biología, Facultad de Ciencias, Universidad del Tolima, Ibagué, Colombia
| | - Susana Caballero
- Laboratorio de Ecología Molecular de Vertebrados Acuáticos (LEMVA), Departamento de Ciencias Biológicas, Universidad de los Andes, Bogotá, Colombia
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Burgarella C, Barnaud A, Kane NA, Jankowski F, Scarcelli N, Billot C, Vigouroux Y, Berthouly-Salazar C. Adaptive Introgression: An Untapped Evolutionary Mechanism for Crop Adaptation. FRONTIERS IN PLANT SCIENCE 2019; 10:4. [PMID: 30774638 PMCID: PMC6367218 DOI: 10.3389/fpls.2019.00004] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 01/04/2019] [Indexed: 05/18/2023]
Abstract
Global environmental changes strongly impact wild and domesticated species biology and their associated ecosystem services. For crops, global warming has led to significant changes in terms of phenology and/or yield. To respond to the agricultural challenges of this century, there is a strong need for harnessing the genetic variability of crops and adapting them to new conditions. Gene flow, from either the same species or a different species, may be an immediate primary source to widen genetic diversity and adaptions to various environments. When the incorporation of a foreign variant leads to an increase of the fitness of the recipient pool, it is referred to as "adaptive introgression". Crop species are excellent case studies of this phenomenon since their genetic variability has been considerably reduced over space and time but most of them continue exchanging genetic material with their wild relatives. In this paper, we review studies of adaptive introgression, presenting methodological approaches and challenges to detecting it. We pay particular attention to the potential of this evolutionary mechanism for the adaptation of crops. Furthermore, we discuss the importance of farmers' knowledge and practices in shaping wild-to-crop gene flow. Finally, we argue that screening the wild introgression already existing in the cultivated gene pool may be an effective strategy for uncovering wild diversity relevant for crop adaptation to current environmental changes and for informing new breeding directions.
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Affiliation(s)
- Concetta Burgarella
- Institut de Recherche pour le Développement, UMR DIADE, Montpellier, France
- DIADE, Université de Montpellier, Montpellier, France
- Centre de Coopération Internationale en Recherche Agronomique pour le Développement, UMR AGAP, Montpellier, France
- AGAP, Université de Montpellier, Centre de Coopération Internationale en Recherche Agronomique pour le Développement, Institut National de la Recherche Agronomique, Montpellier SupAgro, Montpellier, France
- *Correspondence: Concetta Burgarella, Cécile Berthouly-Salazar,
| | - Adeline Barnaud
- Institut de Recherche pour le Développement, UMR DIADE, Montpellier, France
- DIADE, Université de Montpellier, Montpellier, France
| | - Ndjido Ardo Kane
- Laboratoire National de Recherches sur les Productions Végétales, Institut Sénégalais de Recherches Agricoles, Dakar, Senegal
- Laboratoire Mixte International Adaptation des Plantes et Microorganismes Associés aux Stress Environnementaux, Dakar, Senegal
| | - Frédérique Jankowski
- Centre de Coopération Internationale en Recherche Agronomique pour le Développement, UPR GREEN, Montpellier, France
- GREEN, Centre de Coopération Internationale en Recherche Agronomique pour le Développement, Université de Montpellier, Montpellier, France
- Bureau d’Analyses Macro-Economiques, Institut Sénégalais de Recherches Agricoles, Dakar, Senegal
| | - Nora Scarcelli
- Institut de Recherche pour le Développement, UMR DIADE, Montpellier, France
- DIADE, Université de Montpellier, Montpellier, France
| | - Claire Billot
- Centre de Coopération Internationale en Recherche Agronomique pour le Développement, UMR AGAP, Montpellier, France
- AGAP, Université de Montpellier, Centre de Coopération Internationale en Recherche Agronomique pour le Développement, Institut National de la Recherche Agronomique, Montpellier SupAgro, Montpellier, France
| | - Yves Vigouroux
- Institut de Recherche pour le Développement, UMR DIADE, Montpellier, France
- DIADE, Université de Montpellier, Montpellier, France
| | - Cécile Berthouly-Salazar
- Institut de Recherche pour le Développement, UMR DIADE, Montpellier, France
- DIADE, Université de Montpellier, Montpellier, France
- Laboratoire Mixte International Adaptation des Plantes et Microorganismes Associés aux Stress Environnementaux, Dakar, Senegal
- *Correspondence: Concetta Burgarella, Cécile Berthouly-Salazar,
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79
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Liu L, Anderson C, Pearl D, Edwards SV. Modern Phylogenomics: Building Phylogenetic Trees Using the Multispecies Coalescent Model. Methods Mol Biol 2019; 1910:211-239. [PMID: 31278666 DOI: 10.1007/978-1-4939-9074-0_7] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The multispecies coalescent (MSC) model provides a compelling framework for building phylogenetic trees from multilocus DNA sequence data. The pure MSC is best thought of as a special case of so-called "multispecies network coalescent" models, in which gene flow is allowed among branches of the tree, whereas MSC methods assume there is no gene flow between diverging species. Early implementations of the MSC, such as "parsimony" or "democratic vote" approaches to combining information from multiple gene trees, as well as concatenation, in which DNA sequences from multiple gene trees are combined into a single "supergene," were quickly shown to be inconsistent in some regions of tree space, in so far as they converged on the incorrect species tree as more gene trees and sequence data were accumulated. The anomaly zone, a region of tree space in which the most frequent gene tree is different from the species tree, is one such region where many so-called "coalescent" methods are inconsistent. Second-generation implementations of the MSC employed Bayesian or likelihood models; these are consistent in all regions of gene tree space, but Bayesian methods in particular are incapable of handling the large phylogenomic data sets currently available. Two-step methods, such as MP-EST and ASTRAL, in which gene trees are first estimated and then combined to estimate an overarching species tree, are currently popular in part because they can handle large phylogenomic data sets. These methods are consistent in the anomaly zone but can sometimes provide inappropriate measures of tree support or apportion error and signal in the data inappropriately. MP-EST in particular employs a likelihood model which can be conveniently manipulated to perform statistical tests of competing species trees, incorporating the likelihood of the collected gene trees on each species tree in a likelihood ratio test. Such tests provide a useful alternative to the multilocus bootstrap, which only indirectly tests the appropriateness of competing species trees. We illustrate these tests and implementations of the MSC with examples and suggest that MSC methods are a useful class of models effectively using information from multiple loci to build phylogenetic trees.
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Affiliation(s)
- Liang Liu
- Department of Statistics, University of Georgia, Athens, GA, USA
| | | | - Dennis Pearl
- Department of Statistics, Pennsylvania State University, University Park, PA, USA
| | - Scott V Edwards
- Department of Organismic and Evolutionary Biology & Museum of Comparative Zoology, Harvard University, Cambridge, MA, USA.
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80
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Leaché AD, Zhu T, Rannala B, Yang Z. The Spectre of Too Many Species. Syst Biol 2019; 68:168-181. [PMID: 29982825 PMCID: PMC6292489 DOI: 10.1093/sysbio/syy051] [Citation(s) in RCA: 140] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 06/29/2018] [Accepted: 06/29/2018] [Indexed: 11/21/2022] Open
Abstract
Recent simulation studies examining the performance of Bayesian species delimitation as implemented in the bpp program have suggested that bpp may detect population splits but not species divergences and that it tends to over-split when data of many loci are analyzed. Here, we confirm these results and provide the mathematical justifications. We point out that the distinction between population and species splits made in the protracted speciation model (PSM) has no influence on the generation of gene trees and sequence data, which explains why no method can use such data to distinguish between population splits and speciation. We suggest that the PSM is unrealistic as its mechanism for assigning species status assumes instantaneous speciation, contradicting prevailing taxonomic practice. We confirm the suggestion, based on simulation, that in the case of speciation with gene flow, Bayesian model selection as implemented in bpp tends to detect population splits when the amount of data (the number of loci) increases. We discuss the use of a recently proposed empirical genealogical divergence index (gdi) for species delimitation and illustrate that parameter estimates produced by a full likelihood analysis as implemented in bpp provide much more reliable inference under the gdi than the approximate method phrapl. We distinguish between Bayesian model selection and parameter estimation and suggest that the model selection approach is useful for identifying sympatric cryptic species, while the parameter estimation approach may be used to implement empirical criteria for determining species status among allopatric populations.
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Affiliation(s)
- Adam D Leaché
- Department of Biology & Burke Museum of Natural History and Culture, University of Washington, Seattle, USA
| | - Tianqi Zhu
- National Center for Mathematics and Interdisciplinary Sciences, Academy of Mathematics and Systems Science, Chinese Academy of Sciences, China
- Key Laboratory of Random Complex Structures and Data Science, Academy of Mathematics and Systems Science, Chinese Academy of Sciences, China
| | - Bruce Rannala
- Department of Evolution and Ecology, University of California Davis, One Shields Avenue, Davis, USA
| | - Ziheng Yang
- National Center for Mathematics and Interdisciplinary Sciences, Academy of Mathematics and Systems Science, Chinese Academy of Sciences, China
- Department of Genetics, University College London, London, UK
- Radcliffe Institute for Advanced Studies, Harvard University, Cambridge, USA
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81
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Evidence for divergent patterns of local selection driving venom variation in Mojave Rattlesnakes (Crotalus scutulatus). Sci Rep 2018; 8:17622. [PMID: 30514908 PMCID: PMC6279745 DOI: 10.1038/s41598-018-35810-9] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 11/09/2018] [Indexed: 01/20/2023] Open
Abstract
Snake venoms represent an enriched system for investigating the evolutionary processes that lead to complex and dynamic trophic adaptations. It has long been hypothesized that natural selection may drive geographic variation in venom composition, yet previous studies have lacked the population genetic context to examine these patterns. We leverage range-wide sampling of Mojave Rattlesnakes (Crotalus scutulatus) and use a combination of venom, morphological, phylogenetic, population genetic, and environmental data to characterize the striking dichotomy of neurotoxic (Type A) and hemorrhagic (Type B) venoms throughout the range of this species. We find that three of the four previously identified major lineages within C. scutulatus possess a combination of Type A, Type B, and a ‘mixed’ Type A + B venom phenotypes, and that fixation of the two main venom phenotypes occurs on a more fine geographic scale than previously appreciated. We also find that Type A + B individuals occur in regions of inferred introgression, and that this mixed phenotype is comparatively rare. Our results support strong directional local selection leading to fixation of alternative venom phenotypes on a fine geographic scale, and are inconsistent with balancing selection to maintain both phenotypes within a single population. Our comparisons to biotic and abiotic factors further indicate that venom phenotype correlates with fang morphology and climatic variables. We hypothesize that links to fang morphology may be indicative of co-evolution of venom and other trophic adaptations, and that climatic variables may be linked to prey distributions and/or physiology, which in turn impose selection pressures on snake venoms.
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82
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Provost KL, Mauck WM, Smith BT. Genomic divergence in allopatric Northern Cardinals of the North American warm deserts is linked to behavioral differentiation. Ecol Evol 2018; 8:12456-12478. [PMID: 30619558 PMCID: PMC6309012 DOI: 10.1002/ece3.4596] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Revised: 09/06/2018] [Accepted: 09/07/2018] [Indexed: 01/22/2023] Open
Abstract
Biogeographic barriers are considered important in initiating speciation through geographic isolation, but they rarely indiscriminately and completely reduce gene flow across entire communities. Explicitly demonstrating which factors are associated with gene-flow levels across barriers would help elucidate how speciation is initiated and isolation maintained. Here, we investigated the association of behavioral isolation on population differentiation in Northern Cardinals (Cardinalis cardinalis) distributed across the Cochise Filter Barrier, a region of transitional habitat which separates the Sonoran and Chihuahuan deserts of North America. Using genomewide markers, we modeled demographic history by fitting the data to isolation and isolation-with-migration models. The best-fit model indicated that desert populations diverged in the Pleistocene with low, historic, and asymmetric gene flow across the barrier. We then tested behavioral isolation using reciprocal call-broadcast experiments to compare song recognition between deserts, controlling for song dialect changes within deserts. We found that male Northern Cardinals in both deserts were most aggressive to local songs and failed to recognize across-barrier songs. A correlation of genomic differentiation and strong song discrimination is consistent with a model where speciation is initiated across a barrier and maintained by behavioral isolation.
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Affiliation(s)
- Kaiya L. Provost
- Department of OrnithologyAmerican Museum of Natural HistoryNew YorkNew York
- Department of Ecology, Evolution, and Environmental BiologyColumbia UniversityNew YorkNew York
- Richard Gilder Graduate SchoolAmerican Museum of Natural HistoryNew YorkNew York
| | - William M. Mauck
- Department of OrnithologyAmerican Museum of Natural HistoryNew YorkNew York
- Present address:
New York Genome CenterNew YorkNew York
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83
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Leimar O, Dall SRX, McNamara JM, Kuijper B, Hammerstein P. Ecological Genetic Conflict: Genetic Architecture Can Shift the Balance between Local Adaptation and Plasticity. Am Nat 2018; 193:70-80. [PMID: 30624104 DOI: 10.1086/700719] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Genetic polymorphism can contribute to local adaptation in heterogeneous habitats, for instance, as a single locus with alleles adapted to different habitats. Phenotypic plasticity can also contribute to trait variation across habitats, through developmental responses to habitat-specific cues. We show that the genetic architecture of genetically polymorphic and plasticity loci may influence the balance between local adaptation and phenotypic plasticity. These effects of genetic architecture are instances of ecological genetic conflict. A reduced effective migration rate for genes tightly linked to a genetic polymorphism provides an explanation for the effects, and they can occur both for a single trait and for a syndrome of coadapted traits. Using individual-based simulations and numerical analysis, we investigate how among-habitat genetic polymorphism and phenotypic plasticity depend on genetic architecture. We also study the evolution of genetic architecture itself, in the form of rates of recombination between genetically polymorphic loci and plasticity loci. Our main result is that for plasticity genes that are unlinked to loci with between-habitat genetic polymorphism, the slope of a reaction norm is steeper in comparison with the slope favored by plasticity genes that are tightly linked to genes for local adaptation.
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84
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Veale AJ, Foster BJ, Dearden PK, Waters JM. Genotyping-by-sequencing supports a genetic basis for wing reduction in an alpine New Zealand stonefly. Sci Rep 2018; 8:16275. [PMID: 30389951 PMCID: PMC6215011 DOI: 10.1038/s41598-018-34123-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Accepted: 10/09/2018] [Indexed: 12/19/2022] Open
Abstract
Wing polymorphism is a prominent feature of numerous insect groups, but the genomic basis for this diversity remains poorly understood. Wing reduction is a commonly observed trait in many species of stoneflies, particularly in cold or alpine environments. The widespread New Zealand stonefly Zelandoperla fenestrata species group (Z. fenestrata, Z. tillyardi, Z. pennulata) contains populations ranging from fully winged (macropterous) to vestigial-winged (micropterous), with the latter phenotype typically associated with high altitudes. The presence of flightless forms on numerous mountain ranges, separated by lowland fully winged populations, suggests wing reduction has occurred multiple times. We use Genotyping by Sequencing (GBS) to test for genetic differentiation between fully winged (n = 62) and vestigial-winged (n = 34) individuals, sampled from a sympatric population of distinct wing morphotypes, to test for a genetic basis for wing morphology. While we found no population genetic differentiation between these two morphotypes across 6,843 SNP loci, we did detect several outlier loci that strongly differentiated morphotypes across independent tests. These findings indicate that small regions of the genome are likely to be highly differentiated between morphotypes, suggesting a genetic basis for wing reduction. Our results provide a clear basis for ongoing genomic analysis to elucidate critical regulatory pathways for wing development in Pterygota.
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Affiliation(s)
- Andrew J Veale
- Department of Zoology, University of Otago, Dunedin, 9016, New Zealand
- Department of Environmental and Animal Sciences, Unitec, Auckland, 1025, New Zealand
| | - Brodie J Foster
- Department of Zoology, University of Otago, Dunedin, 9016, New Zealand
| | - Peter K Dearden
- Genomics Aotearoa and Department of Biochemistry, University of Otago, Dunedin, 9016, New Zealand
| | - Jonathan M Waters
- Department of Zoology, University of Otago, Dunedin, 9016, New Zealand.
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85
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Hey J, Chung Y, Sethuraman A, Lachance J, Tishkoff S, Sousa VC, Wang Y. Phylogeny Estimation by Integration over Isolation with Migration Models. Mol Biol Evol 2018; 35:2805-2818. [PMID: 30137463 PMCID: PMC6231491 DOI: 10.1093/molbev/msy162] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Phylogeny estimation is difficult for closely related populations and species, especially if they have been exchanging genes. We present a hierarchical Bayesian, Markov-chain Monte Carlo method with a state space that includes all possible phylogenies in a full Isolation-with-Migration model framework. The method is based on a new type of genealogy augmentation called a "hidden genealogy" that enables efficient updating of the phylogeny. This is the first likelihood-based method to fully incorporate directional gene flow and genetic drift for estimation of a species or population phylogeny. Application to human hunter-gatherer populations from Africa revealed a clear phylogenetic history, with strong support for gene exchange with an unsampled ghost population, and relatively ancient divergence between a ghost population and modern human populations, consistent with human/archaic divergence. In contrast, a study of five chimpanzee populations reveals a clear phylogeny with several pairs of populations having exchanged DNA, but does not support a history with an unsampled ghost population.
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Affiliation(s)
- Jody Hey
- Department of Biology, Center for Computational Genetics and Genomics, Temple University, Philadelphia, PA
| | - Yujin Chung
- Department of Biology, Center for Computational Genetics and Genomics, Temple University, Philadelphia, PA
- The Department of Applied Statistics, Kyonggi University, Suwon, South Korea
| | - Arun Sethuraman
- Department of Biology, Center for Computational Genetics and Genomics, Temple University, Philadelphia, PA
- Department of Biological Sciences, California State University San Marcos, San Marcos, CA
| | - Joseph Lachance
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
- Georgia Institute of Technology, Atlanta, GA
| | - Sarah Tishkoff
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Vitor C Sousa
- Department of Genetics, Rutgers, the State University of New Jersey, Piscataway, NJ
- University of Lisbon, Lisboa, Portugal
| | - Yong Wang
- Department of Genetics, Rutgers, the State University of New Jersey, Piscataway, NJ
- Ancestry, San Francisco, CA
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86
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Tang Q, Edwards SV, Rheindt FE. Rapid diversification and hybridization have shaped the dynamic history of the genus Elaenia. Mol Phylogenet Evol 2018; 127:522-533. [DOI: 10.1016/j.ympev.2018.05.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Revised: 04/11/2018] [Accepted: 05/08/2018] [Indexed: 01/04/2023]
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87
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Bertl J, Ringbauer H, Blum MG. Can secondary contact following range expansion be distinguished from barriers to gene flow? PeerJ 2018; 6:e5325. [PMID: 30294507 PMCID: PMC6171497 DOI: 10.7717/peerj.5325] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 07/01/2018] [Indexed: 11/20/2022] Open
Abstract
Secondary contact is the reestablishment of gene flow between sister populations that have diverged. For instance, at the end of the Quaternary glaciations in Europe, secondary contact occurred during the northward expansion of the populations which had found refugia in the southern peninsulas. With the advent of multi-locus markers, secondary contact can be investigated using various molecular signatures including gradients of allele frequency, admixture clines, and local increase of genetic differentiation. We use coalescent simulations to investigate if molecular data provide enough information to distinguish between secondary contact following range expansion and an alternative evolutionary scenario consisting of a barrier to gene flow in an isolation-by-distance model. We find that an excess of linkage disequilibrium and of genetic diversity at the suture zone is a unique signature of secondary contact. We also find that the directionality index ψ, which was proposed to study range expansion, is informative to distinguish between the two hypotheses. However, although evidence for secondary contact is usually conveyed by statistics related to admixture coefficients, we find that they can be confounded by isolation-by-distance. We recommend to account for the spatial repartition of individuals when investigating secondary contact in order to better reflect the complex spatio-temporal evolution of populations and species.
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Affiliation(s)
- Johanna Bertl
- Department of Molecular Medicine, Aarhus University, Aarhus, Denmark
- Vienna Graduate School of Population Genetics, Vetmeduni Vienna, Vienna, Austria
| | - Harald Ringbauer
- Department of Human Genetics, University of Chicago, Chicago, IL, USA
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Michael G.B. Blum
- Laboratoire TIMC-IMAG, UMR 5525, Université Grenoble Alpes, CNRS, Grenoble, France
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88
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Wu W, Ng WL, Yang JX, Li WM, Ge XJ. High cryptic species diversity is revealed by genome-wide polymorphisms in a wild relative of banana, Musa itinerans, and implications for its conservation in subtropical China. BMC PLANT BIOLOGY 2018; 18:194. [PMID: 30217175 PMCID: PMC6137913 DOI: 10.1186/s12870-018-1410-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 08/31/2018] [Indexed: 06/08/2023]
Abstract
BACKGROUND Species delimitation is a challenging but essential task in conservation biology. Morphologically similar species are sometimes difficult to recognize even after examination by experienced taxonomists. With the advent of molecular approaches in species delimitation, this hidden diversity has received much recent attention. In addition to DNA barcoding approaches, analytical tools based on the multi-species coalescence model (MSC) have been developed for species delimitation. Musa itinerans is widely distributed in subtropical Asia, and at least six varieties have been documented. However, the number of evolutionarily distinct lineages remains unknown. RESULTS Using genome resequencing data of five populations (making up four varieties), we examined genome-wide variation and found four varieties that were evolutionary significant units. A Bayesian Phylogenetics and Phylogeography (BP&P) analysis using 123 single copy nuclear genes support three speciation events of M. itinerans varieties with robust posterior speciation probabilities; However, a Bayes factor delimitation of species with genomic data (BFD*) analysis using 1201 unlinked single nucleotide polymorphisms gave decisive support for a five-lineage model. When reconciling divergence time estimates with a speciation time scale, a modified three-lineage model was consistent with that of BP&P, in which the speciation time of two varieties (M. itinerans var. itinerans and M. itinerans var. lechangensis) were dated to 26.2 kya and 10.7 kya, respectively. In contrast, other two varieties (M. itinerans var. chinensis and M. itinerans var. guangdongensis) diverged only 3.8 kya in the Anthropocene; this may be a consequence of genetic drift rather than a speciation event. CONCLUSION Our results showed that the M. itinerans species complex harbours high cryptic species diversity. We recommend that M. itinerans var. itinerans and M. itinerans var. lechangensis be elevated to subspecies status, and the extremely rare latter subspecies be given priority for conservation. We also recommend that the very recently diverged M. itinerans var. chinensis and M. itinerans var. guangdongensis should be merged under the subspecies M. itinerans var. chinensis. Finally, we speculate that species delimitation of recently diverged lineages may be more effective using genome-wide bi-allelic SNP markers with BFD* than by using unlinked loci and BP&P.
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Affiliation(s)
- Wei Wu
- State Key Laboratory of Biocontrol, Sun Yat-sen University, Guangzhou, 510275 China
| | - Wei-Lun Ng
- State Key Laboratory of Biocontrol, Sun Yat-sen University, Guangzhou, 510275 China
| | - Jun-Xin Yang
- Center for Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101 China
| | - Wei-Ming Li
- Key Laboratory of Tropical Fruit Biology, Ministry of Agriculture, South Subtropical Crops Research Institute, Chinese Academy of Tropical Agricultural Sciences, Zhanjiang, 524091 China
| | - Xue-Jun Ge
- Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, the Chinese Academy of Sciences, Guangzhou, 510650 China
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89
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Bono JM, Pigage HK, Wettstein PJ, Prosser SA, Pigage JC. Genome-wide markers reveal a complex evolutionary history involving divergence and introgression in the Abert's squirrel (Sciurus aberti) species group. BMC Evol Biol 2018; 18:139. [PMID: 30208839 PMCID: PMC6134581 DOI: 10.1186/s12862-018-1248-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Accepted: 08/20/2018] [Indexed: 01/09/2023] Open
Abstract
Background Genetic introgression between divergent lineages is now considered more common than previously appreciated, with potentially important consequences for adaptation and speciation. Introgression is often asymmetric between populations and patterns can vary for different types of loci (nuclear vs. organellar), complicating phylogeographic reconstruction. The taxonomy of the ecologically specialized Abert’s squirrel species group has been controversial, and previous studies based on mitochondrial data have not fully resolved the evolutionary relationships among populations. Moreover, while these studies identified potential areas of secondary contact between divergent lineages, the possibility for introgression has not been tested. Results We used RAD-seq to unravel the complex evolutionary history of the Abert’s squirrel species group. Although some of our findings reinforce inferences based on mitochondrial data, we also find significant areas of discordance. Discordant signals generally arise from previously undetected introgression between divergent populations that differentially affected variation at mitochondrial and nuclear loci. Most notably, our results support earlier claims (disputed by mitochondrial data) that S. aberti kaibabensis, found only on the north rim of the Grand Canyon, is highly divergent from other populations. However, we also detected introgression of S. aberti kaibabensis DNA into other S. aberti populations, which likely accounts for the previously inferred close genetic relationship between this population and those south of the Grand Canyon. Conclusions Overall, the evolutionary history of Abert’s squirrels appears to be shaped largely by divergence during periods of habitat isolation. However, we also found evidence for interbreeding during periods of secondary contact resulting in introgression, with variable effects on mitochondrial and nuclear markers. Our results support the emerging view that populations often diversify under scenarios involving both divergence in isolation and gene flow during secondary contact, and highlight the value of genome-wide datasets for resolving such complex evolutionary histories. Electronic supplementary material The online version of this article (10.1186/s12862-018-1248-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jeremy M Bono
- Department of Biology, University of Colorado Colorado Springs, Colorado Springs, CO, 80918, USA.
| | - Helen K Pigage
- Department of Biology, University of Colorado Colorado Springs, Colorado Springs, CO, 80918, USA
| | - Peter J Wettstein
- Department of Surgery, Mayo Clinic, 200 First St. SW, Rochester, MN, 55905, USA
| | - Stephanie A Prosser
- Department of Biology, University of Colorado Colorado Springs, Colorado Springs, CO, 80918, USA
| | - Jon C Pigage
- Department of Biology, University of Colorado Colorado Springs, Colorado Springs, CO, 80918, USA
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90
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Westram AM, Rafajlović M, Chaube P, Faria R, Larsson T, Panova M, Ravinet M, Blomberg A, Mehlig B, Johannesson K, Butlin R. Clines on the seashore: The genomic architecture underlying rapid divergence in the face of gene flow. Evol Lett 2018; 2:297-309. [PMID: 30283683 PMCID: PMC6121805 DOI: 10.1002/evl3.74] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 06/14/2018] [Accepted: 06/29/2018] [Indexed: 12/16/2022] Open
Abstract
Adaptive divergence and speciation may happen despite opposition by gene flow. Identifying the genomic basis underlying divergence with gene flow is a major task in evolutionary genomics. Most approaches (e.g., outlier scans) focus on genomic regions of high differentiation. However, not all genomic architectures potentially underlying divergence are expected to show extreme differentiation. Here, we develop an approach that combines hybrid zone analysis (i.e., focuses on spatial patterns of allele frequency change) with system-specific simulations to identify loci inconsistent with neutral evolution. We apply this to a genome-wide SNP set from an ideally suited study organism, the intertidal snail Littorina saxatilis, which shows primary divergence between ecotypes associated with different shore habitats. We detect many SNPs with clinal patterns, most of which are consistent with neutrality. Among non-neutral SNPs, most are located within three large putative inversions differentiating ecotypes. Many non-neutral SNPs show relatively low levels of differentiation. We discuss potential reasons for this pattern, including loose linkage to selected variants, polygenic adaptation and a component of balancing selection within populations (which may be expected for inversions). Our work is in line with theory predicting a role for inversions in divergence, and emphasizes that genomic regions contributing to divergence may not always be accessible with methods purely based on allele frequency differences. These conclusions call for approaches that take spatial patterns of allele frequency change into account in other systems.
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Affiliation(s)
- Anja M. Westram
- Department of Animal and Plant SciencesUniversity of SheffieldUK
- Current address: IST AustriaAm Campus 13400KlosterneuburgAustria
| | - Marina Rafajlović
- Department of Marine SciencesUniversity of Gothenburg40530GothenburgSweden
- Department of PhysicsUniversity of Gothenburg41296GothenburgSweden
| | - Pragya Chaube
- Department of Animal and Plant SciencesUniversity of SheffieldUK
| | - Rui Faria
- Department of Animal and Plant SciencesUniversity of SheffieldUK
| | - Tomas Larsson
- Department of Marine SciencesUniversity of Gothenburg40530GothenburgSweden
| | - Marina Panova
- Department of Marine Sciences ‐ TjärnöUniversity of Gothenburg45296StrömstadSweden
| | - Mark Ravinet
- CEES (Centre for Ecological and Evolutionary Synthesis)University of OsloOslo0316Norway
| | - Anders Blomberg
- Department of Chemistry and Molecular BiologyUniversity of Gothenburg40530GothenburgSweden
| | - Bernhard Mehlig
- Department of PhysicsUniversity of Gothenburg41296GothenburgSweden
| | - Kerstin Johannesson
- Department of Marine Sciences ‐ TjärnöUniversity of Gothenburg45296StrömstadSweden
| | - Roger Butlin
- Department of Animal and Plant SciencesUniversity of SheffieldUK
- Department of Marine Sciences ‐ TjärnöUniversity of Gothenburg45296StrömstadSweden
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91
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He Z, Li X, Yang M, Wang X, Zhong C, Duke NC, Wu CI, Shi S. Speciation with gene flow via cycles of isolation and migration: insights from multiple mangrove taxa. Natl Sci Rev 2018; 6:275-288. [PMID: 31258952 PMCID: PMC6599600 DOI: 10.1093/nsr/nwy078] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Allopatric speciation requiring an unbroken period of geographical isolation has been the standard model of neo-Darwinism. While doubts have been repeatedly raised, strict allopatry without any gene flow remains a plausible mechanism in most cases. To rigorously reject strict allopatry, genomic sequences superimposed on the geological records of a well-delineated geographical barrier are necessary. The Strait of Malacca, narrowly connecting the Pacific and Indian Ocean coasts, serves at different times either as a geographical barrier or a conduit of gene flow for coastal/marine species. We surveyed 1700 plants from 29 populations of 5 common mangrove species by large-scale DNA sequencing and added several whole-genome assemblies. Speciation between the two oceans is driven by cycles of isolation and gene flow due to the fluctuations in sea level leading to the opening/closing of the Strait to ocean currents. Because the time required for speciation in mangroves is longer than the isolation phases, speciation in these mangroves has proceeded through many cycles of mixing-isolation-mixing, or MIM, cycles. The MIM mechanism, by relaxing the condition of no gene flow, can promote speciation in many more geographical features than strict allopatry can. Finally, the MIM mechanism of speciation is also efficient, potentially yielding mn (m > 1) species after n cycles.
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Affiliation(s)
- Ziwen He
- State Key Laboratory of Biocontrol, Guangdong Key Lab of Plant Resources, Key Laboratory of Biodiversity Dynamics and Conservation of Guangdong Higher Education Institutes, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China
| | - Xinnian Li
- State Key Laboratory of Biocontrol, Guangdong Key Lab of Plant Resources, Key Laboratory of Biodiversity Dynamics and Conservation of Guangdong Higher Education Institutes, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China
| | - Ming Yang
- State Key Laboratory of Biocontrol, Guangdong Key Lab of Plant Resources, Key Laboratory of Biodiversity Dynamics and Conservation of Guangdong Higher Education Institutes, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China
| | - Xinfeng Wang
- State Key Laboratory of Biocontrol, Guangdong Key Lab of Plant Resources, Key Laboratory of Biodiversity Dynamics and Conservation of Guangdong Higher Education Institutes, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China
| | - Cairong Zhong
- Hainan Dongzhai Harbor National Nature Reserve Administration, Haikou 571129, China
| | - Norman C Duke
- Centre for Tropical Water and Aquatic Ecosystem Research, James Cook University, Townsville 4811, Australia
| | - Chung-I Wu
- State Key Laboratory of Biocontrol, Guangdong Key Lab of Plant Resources, Key Laboratory of Biodiversity Dynamics and Conservation of Guangdong Higher Education Institutes, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China.,CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100101, China.,Department of Ecology and Evolution, University of Chicago, Chicago IL 60637, USA
| | - Suhua Shi
- State Key Laboratory of Biocontrol, Guangdong Key Lab of Plant Resources, Key Laboratory of Biodiversity Dynamics and Conservation of Guangdong Higher Education Institutes, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China
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92
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Fuller ZL, Leonard CJ, Young RE, Schaeffer SW, Phadnis N. Ancestral polymorphisms explain the role of chromosomal inversions in speciation. PLoS Genet 2018; 14:e1007526. [PMID: 30059505 PMCID: PMC6085072 DOI: 10.1371/journal.pgen.1007526] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 08/09/2018] [Accepted: 06/29/2018] [Indexed: 01/28/2023] Open
Abstract
Understanding the role of chromosomal inversions in speciation is a fundamental problem in evolutionary genetics. Here, we perform a comprehensive reconstruction of the evolutionary histories of the chromosomal inversions in Drosophila persimilis and D. pseudoobscura. We provide a solution to the puzzling origins of the selfish Sex-Ratio arrangement in D. persimilis and uncover surprising patterns of phylogenetic discordance on this chromosome. These patterns show that, contrary to widely held views, all fixed chromosomal inversions between D. persimilis and D. pseudoobscura were already present in their ancestral population long before the species split. Our results suggest that patterns of higher genomic divergence and an association of reproductive isolation genes with chromosomal inversions may be a direct consequence of incomplete lineage sorting of ancestral polymorphisms. These findings force a reconsideration of the role of chromosomal inversions in speciation, not as protectors of existing hybrid incompatibilities, but as fertile grounds for their formation.
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Affiliation(s)
- Zachary L. Fuller
- Department of Biology, Erwin W. Mueller Laboratories, The Pennsylvania State University, University Park, PA, United States of America
| | | | - Randee E. Young
- Department of Biology, University of Utah, Salt Lake City, UT, United States of America
| | - Stephen W. Schaeffer
- Department of Biology, Erwin W. Mueller Laboratories, The Pennsylvania State University, University Park, PA, United States of America
| | - Nitin Phadnis
- Department of Biology, University of Utah, Salt Lake City, UT, United States of America
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93
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Campbell CR, Poelstra JW, Yoder AD. What is Speciation Genomics? The roles of ecology, gene flow, and genomic architecture in the formation of species. Biol J Linn Soc Lond 2018. [DOI: 10.1093/biolinnean/bly063] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
| | - J W Poelstra
- Department of Biology, Duke University, Durham, NC, USA
| | - Anne D Yoder
- Department of Biology, Duke University, Durham, NC, USA
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94
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Wang GD, Zhang BL, Zhou WW, Li YX, Jin JQ, Shao Y, Yang HC, Liu YH, Yan F, Chen HM, Jin L, Gao F, Zhang Y, Li H, Mao B, Murphy RW, Wake DB, Zhang YP, Che J. Selection and environmental adaptation along a path to speciation in the Tibetan frog Nanorana parkeri. Proc Natl Acad Sci U S A 2018; 115:E5056-E5065. [PMID: 29760079 PMCID: PMC5984489 DOI: 10.1073/pnas.1716257115] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Tibetan frogs, Nanorana parkeri, are differentiated genetically but not morphologically along geographical and elevational gradients in a challenging environment, presenting a unique opportunity to investigate processes leading to speciation. Analyses of whole genomes of 63 frogs reveal population structuring and historical demography, characterized by highly restricted gene flow in a narrow geographic zone lying between matrilines West (W) and East (E). A population found only along a single tributary of the Yalu Zangbu River has the mitogenome only of E, whereas nuclear genes of W comprise 89-95% of the nuclear genome. Selection accounts for 579 broadly scattered, highly divergent regions (HDRs) of the genome, which involve 365 genes. These genes fall into 51 gene ontology (GO) functional classes, 14 of which are likely to be important in driving reproductive isolation. GO enrichment analyses of E reveal many overrepresented functional categories associated with adaptation to high elevations, including blood circulation, response to hypoxia, and UV radiation. Four genes, including DNAJC8 in the brain, TNNC1 and ADORA1 in the heart, and LAMB3 in the lung, differ in levels of expression between low- and high-elevation populations. High-altitude adaptation plays an important role in maintaining and driving continuing divergence and reproductive isolation. Use of total genomes enabled recognition of selection and adaptation in and between populations, as well as documentation of evolution along a stepped cline toward speciation.
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Affiliation(s)
- Guo-Dong Wang
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China
- Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences, Kunming 650223, China
| | - Bao-Lin Zhang
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China
- Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming 650204, Yunnan, China
| | - Wei-Wei Zhou
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China
- Southeast Asia Biodiversity Research Institute, Chinese Academy of Sciences, Yezin, 05282 Nay Pyi Taw, Myanmar
| | - Yong-Xin Li
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China
- Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming 650204, Yunnan, China
| | - Jie-Qiong Jin
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China
| | - Yong Shao
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China
| | - He-Chuan Yang
- Human Genetics, Genome Institute of Singapore, Agency for Science, Technology and Research, Singapore 138672, Singapore
| | - Yan-Hu Liu
- Laboratory for Conservation and Utilization of Bio-Resources & Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming 650091, China
| | - Fang Yan
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China
| | - Hong-Man Chen
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China
| | - Li Jin
- Key Laboratory of Freshwater Fish Reproduction and Development of the Ministry of Education and Key Laboratory of Aquatic Science of Chongqing, Southwest University School of Life Sciences, Chongqing 400715, China
| | - Feng Gao
- CAS Key Laboratory of Computational Biology, CAS-MPG Partner Institute for Computational Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Yaoguang Zhang
- Key Laboratory of Freshwater Fish Reproduction and Development of the Ministry of Education and Key Laboratory of Aquatic Science of Chongqing, Southwest University School of Life Sciences, Chongqing 400715, China
| | - Haipeng Li
- Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences, Kunming 650223, China
- CAS Key Laboratory of Computational Biology, CAS-MPG Partner Institute for Computational Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Bingyu Mao
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China
- Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences, Kunming 650223, China
| | - Robert W Murphy
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China
- Centre for Biodiversity and Conservation Biology, Royal Ontario Museum, Toronto, ON, Canada M5S 2C6
| | - David B Wake
- Department of Integrative Biology and Museum of Vertebrate Zoology, University of California, Berkeley, CA 94720-3160
| | - Ya-Ping Zhang
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China;
- Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences, Kunming 650223, China
| | - Jing Che
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China;
- Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences, Kunming 650223, China
- Southeast Asia Biodiversity Research Institute, Chinese Academy of Sciences, Yezin, 05282 Nay Pyi Taw, Myanmar
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95
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Sottas C, Reif J, Kuczyński L, Reifová R. Interspecific competition promotes habitat and morphological divergence in a secondary contact zone between two hybridizing songbirds. J Evol Biol 2018; 31:914-923. [PMID: 29603471 DOI: 10.1111/jeb.13275] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Accepted: 03/22/2018] [Indexed: 01/25/2023]
Abstract
Interspecific competition is assumed to play an important role in the ecological differentiation of species and speciation. However, empirical evidence for competition's role in speciation remains surprisingly scarce. Here, we studied the role of interspecific competition in the ecological differentiation and speciation of two closely related songbird species, the Common Nightingale (Luscinia megarhynchos) and the Thrush Nightingale (Luscinia luscinia). Both species are insectivorous and ecologically very similar. They hybridize in a secondary contact zone, which is a mosaic of sites where both species co-occur (syntopy) and sites where only one species is present (allotopy). We analysed fine-scale habitat data for both species in both syntopic and allotopic sites and looked for associations between habitat use and bill morphology, which have been previously shown to be more divergent in sympatry than in allopatry. We found that the two nightingale species differ in habitat use in allotopic sites, where L. megarhynchos occurred in drier habitats and at slightly higher elevations, but not in syntopic sites. Birds from allotopic sites also showed higher interspecific divergence in relative bill size compared to birds from syntopic sites. Finally, we found an association between bill morphology and elevation. Our results are consistent with the view that interspecific competition in nightingales has resulted in partial habitat segregation in sympatry and that the habitat-specific food supply has in turn very likely led to bill size divergence. Such ecological divergence may enhance prezygotic as well as extrinsic postzygotic isolation and thus accelerate the completion of the speciation process.
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Affiliation(s)
- Camille Sottas
- Department of Zoology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Jiří Reif
- Institute for Environmental Studies, Faculty of Science, Charles University, Prague, Czech Republic.,Department of Zoology and Laboratory of Ornithology, Faculty of Science, Palacký University in Olomouc, Olomouc, Czech Republic
| | - Lechosław Kuczyński
- Population Ecology Lab, Institute of Environmental Biology, Faculty of Biology, Adam Mickiewicz University in Poznań, Poznań, Poland
| | - Radka Reifová
- Department of Zoology, Faculty of Science, Charles University, Prague, Czech Republic
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96
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Cao YN, Wang IJ, Chen LY, Ding YQ, Liu LX, Qiu YX. Inferring spatial patterns and drivers of population divergence of Neolitsea sericea (Lauraceae), based on molecular phylogeography and landscape genomics. Mol Phylogenet Evol 2018; 126:162-172. [PMID: 29678646 DOI: 10.1016/j.ympev.2018.04.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2017] [Revised: 03/02/2018] [Accepted: 04/09/2018] [Indexed: 11/24/2022]
Abstract
The relative roles of geography, climate and ecology in driving population divergence and (incipient) speciation has so far been largely neglected in studies addressing the evolution of East Asia's island flora. Here, we employed chloroplast and ribosomal DNA sequences and restriction site-associated DNA sequencing (RADseq) loci to investigate the phylogeography and drivers of population divergence of Neolitsea sericea. These data sets support the subdivision of N. sericea populations into the Southern and Northern lineages across the 'Tokara gap'. Two distinct sublineages were further identified for the Northern lineage of N. sericea from the RADseq data. RADseq was also used along with approximate Bayesian computation to show that the current distribution and differentiation of N. sericea populations resulted from a combination of relatively ancient migration and successive vicariant events that likely occurred during the mid to late Pleistocene. Landscape genomic analyses showed that, apart from geographic barriers, barrier, potentially local adaptation to different climatic conditions appears to be one of the major drivers for lineage diversification of N. sericea.
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Affiliation(s)
- Ya-Nan Cao
- Key Laboratory of Conservation Biology for Endangered Wildlife of the Ministry of Education, and College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Ian J Wang
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA 94720, USA
| | - Lu-Yao Chen
- Key Laboratory of Conservation Biology for Endangered Wildlife of the Ministry of Education, and College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Yan-Qian Ding
- Key Laboratory of Conservation Biology for Endangered Wildlife of the Ministry of Education, and College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Lu-Xian Liu
- Key Laboratory of Conservation Biology for Endangered Wildlife of the Ministry of Education, and College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Ying-Xiong Qiu
- Key Laboratory of Conservation Biology for Endangered Wildlife of the Ministry of Education, and College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China.
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97
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Rutherford S, Rossetto M, Bragg JG, McPherson H, Benson D, Bonser SP, Wilson PG. Speciation in the presence of gene flow: population genomics of closely related and diverging Eucalyptus species. Heredity (Edinb) 2018; 121:126-141. [PMID: 29632325 DOI: 10.1038/s41437-018-0073-2] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 03/12/2018] [Accepted: 03/12/2018] [Indexed: 01/22/2023] Open
Abstract
Speciation is a complex process that is fundamental to the origins of biological diversity. While there has been considerable progress in our understanding of speciation, there are still many unanswered questions, especially regarding barriers to gene flow in diverging populations. Eucalyptus is an appropriate system for investigating speciation mechanisms since it comprises species that are rapidly evolving across heterogeneous environments. We examined patterns of genetic variation within and among six closely related Eucalyptus species in subgenus Eucalyptus section Eucalyptus in south-eastern Australia (commonly known as the "green ashes"). We used reduced representation genome sequencing to genotype samples from populations across altitudinal and latitudinal gradients. We found one species, Eucalyptus cunninghamii, to be highly genetically differentiated from the others, and a population of mallees from Mount Banks to be genetically distinct and therefore likely to be a new undescribed species. Only modest levels of differentiation were found between all other species in the study. There was population structure within some species (e.g., E. obstans) corresponding to geographical factors, indicating that vicariance may have played a role in the evolution of the group. Overall, we found that lineages within the green ashes are differentiated to varying extents, from strongly diverged to much earlier stages of the speciation continuum. Furthermore, our results suggest the green ashes represent a group where a range of mechanisms (e.g., reticulate evolution and vicariance) have been operating in concert. These findings not only offer insights into recent speciation mechanisms in Eucalyptus, but also other species complexes.
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Affiliation(s)
- Susan Rutherford
- Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Sciences, UNSW, Kensington, Sydney, Australia. .,National Herbarium of NSW, Royal Botanic Garden Sydney, Sydney, Australia.
| | - Maurizio Rossetto
- National Herbarium of NSW, Royal Botanic Garden Sydney, Sydney, Australia
| | - Jason G Bragg
- National Herbarium of NSW, Royal Botanic Garden Sydney, Sydney, Australia
| | - Hannah McPherson
- National Herbarium of NSW, Royal Botanic Garden Sydney, Sydney, Australia
| | - Doug Benson
- National Herbarium of NSW, Royal Botanic Garden Sydney, Sydney, Australia
| | - Stephen P Bonser
- Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Sciences, UNSW, Kensington, Sydney, Australia
| | - Peter G Wilson
- National Herbarium of NSW, Royal Botanic Garden Sydney, Sydney, Australia
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98
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Singhal S, Hoskin CJ, Couper P, Potter S, Moritz C. A Framework for Resolving Cryptic Species: A Case Study from the Lizards of the Australian Wet Tropics. Syst Biol 2018; 67:1061-1075. [DOI: 10.1093/sysbio/syy026] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 03/27/2018] [Indexed: 12/19/2022] Open
Affiliation(s)
- Sonal Singhal
- Museum of Zoology and Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Biology, California State University—Dominguez Hills, Carson, CA 90747, USA
| | - Conrad J Hoskin
- College of Science & Engineering, James Cook University, Townsville, Queensland 4811, Australia
| | - Patrick Couper
- Biodiversity Program, Queensland Museum, South Brisbane, Queensland 4101, Australia
| | - Sally Potter
- Division of Ecology and Evolution, Research School of Biology and Centre for Biodiversity Analysis, Australian National University, Acton, ACT 2601, Australia
| | - Craig Moritz
- Division of Ecology and Evolution, Research School of Biology and Centre for Biodiversity Analysis, Australian National University, Acton, ACT 2601, Australia
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99
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Fan Z, Zhou A, Osada N, Yu J, Jiang J, Li P, Du L, Niu L, Deng J, Xu H, Xing J, Yue B, Li J. Ancient hybridization and admixture in macaques (genus Macaca) inferred from whole genome sequences. Mol Phylogenet Evol 2018; 127:376-386. [PMID: 29614345 DOI: 10.1016/j.ympev.2018.03.038] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2017] [Revised: 03/23/2018] [Accepted: 03/30/2018] [Indexed: 12/25/2022]
Abstract
The evolutionary history of the stump-tailed macaque (Macaca arctoides) and its genetic relationship to other macaques is a subject of continuing controversy. Here, we have reported the first genome sequences of two stump-tailed macaques and one Assamese macaque (M. assamensis). Additionally, we have investigated the genetic diversity between macaque species and analyzed ancient hybridization events. Genome-wide analyses demonstrated that the stump-tailed macaque is more closely related to sinica species than to fascicularis/mulatta species. This topology contradicts the mitochondrial sequence-based phylogeny that places the stump-tailed macaque into the fascicularis/mulatta group. However, our results further show that stump-tailed macaques have genetic backgrounds distinct from sinica species, and present evidence of gene flows with rhesus macaques. We suggest that an ancient introgression occurred after stump-tailed macaques diverged from sinica species. The distinct gene flow between proto-arctoides and proto-mulatta resulted in the transfer of rhesus macaque-type mitochondria into proto-arctoides. The rhesus macaque-type mitochondria remained in populations because of genetic drift during the bottleneck. The PSMC results and morphological and geographic evidence are consistent with the mitochondria capture pattern in the stump-tailed macaque. The molecular clock estimates suggest that the mitochondrial transference into stump-tailed macaques occurred 0.4-1.4 million years ago. Furthermore, we detected extensive admixtures between different macaque species, indicating that gene flow has played an important role in the evolutionary history of the genus Macaca.
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Affiliation(s)
- Zhenxin Fan
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, Sichuan, People's Republic of China
| | - Anbo Zhou
- Department of Genetics, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Naoki Osada
- Graduate School of Information Science and Technology, Hokkaido University, Sapporo, Hokkaido 060-0814, Japan
| | - Jianqiu Yu
- Chengdu Zoo, Institute of Chengdu Wildlife, Chengdu 610081, People's Republic of China
| | - Juan Jiang
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, Sichuan, People's Republic of China
| | - Peng Li
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, Sichuan, People's Republic of China
| | - Lianming Du
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, Sichuan, People's Republic of China
| | - Lili Niu
- Chengdu Zoo, Institute of Chengdu Wildlife, Chengdu 610081, People's Republic of China
| | - Jiabo Deng
- Chengdu Zoo, Institute of Chengdu Wildlife, Chengdu 610081, People's Republic of China
| | - Huailiang Xu
- College of Animal Science and Technology, Sichuan Agricultural University, Ya'an, People's Republic of China
| | - Jinchuan Xing
- Department of Genetics, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Bisong Yue
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, Sichuan, People's Republic of China.
| | - Jing Li
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, Sichuan, People's Republic of China.
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100
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Schwenke PL, Park LK, Hauser L. Introgression among three rockfish species (Sebastes spp.) in the Salish Sea, northeast Pacific Ocean. PLoS One 2018; 13:e0194068. [PMID: 29566070 PMCID: PMC5864001 DOI: 10.1371/journal.pone.0194068] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 02/25/2018] [Indexed: 11/18/2022] Open
Abstract
Interspecific hybridization is often seen as a major conservation issue, potentially threatening endangered species and decreasing biodiversity. In natural populations, the conservation implications of hybridization depends on both on anthropogenic factors and the evolutionary processes maintaining the hybrid zone. However, the timeline and patterns of hybridization in the hybrid zone are often not known. Therefore, species conservation becomes a concern when recent anthropogenic changes influence hybridization and not if hybridization is part of a long-term process. Here, we use sequence data from one mitochondrial gene, three nuclear introns and one nuclear exon to estimate the direction, geographic extent, frequency and possible timeline of hybridization between three rockfish species (Sebastes auriculatus, S. caurinus, S. maliger) in the Salish Sea, Washington, USA. We show that (i) introgression occurred much more frequently in the Salish Sea than on the outer coast, (ii) introgression was highly asymmetrical from S. maliger into the other two species, (iii) almost 40% of individuals in the Salish Sea were hybrids, with frequency of hybrids increasing with isolation from the coast, and (iv) all hybrids were later generation backcrosses rather than F1 hybrids. Our results suggest long-standing low-level hybridization rather than recent onset of interbreeding because of human induced environmental change, possibly facilitated by specific environmental conditions in the sub-basins of the Salish Sea, and by differences in population sizes during recolonization of the area after the last glaciation. This rockfish hybrid system, with asymmetrical introgression and the maintenance of parental species, may prove useful to study both mechanisms that maintain species boundaries and that facilitate speciation in the presence of rapid environmental change.
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Affiliation(s)
- Piper L. Schwenke
- Conservation Biology Division, Northwest Fisheries Science Center, National Marine Fisheries Service, Seattle, Washington, United States of America
- School of Aquatic and Fishery Sciences, University of Washington, Seattle, Washington, United States of America
- * E-mail:
| | - Linda K. Park
- Conservation Biology Division, Northwest Fisheries Science Center, National Marine Fisheries Service, Seattle, Washington, United States of America
| | - Lorenz Hauser
- School of Aquatic and Fishery Sciences, University of Washington, Seattle, Washington, United States of America
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