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Pyron RA, Kakkera A, Beamer DA, O'Connell KA. Discerning structure versus speciation in phylogeographic analysis of Seepage Salamanders (Desmognathus aeneus) using demography, environment, geography, and phenotype. Mol Ecol 2024; 33:e17219. [PMID: 38015012 DOI: 10.1111/mec.17219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 10/26/2023] [Accepted: 11/13/2023] [Indexed: 11/29/2023]
Abstract
Numerous mechanisms can drive speciation, including isolation by adaptation, distance, and environment. These forces can promote genetic and phenotypic differentiation of local populations, the formation of phylogeographic lineages, and ultimately, completed speciation. However, conceptually similar mechanisms may also result in stabilizing rather than diversifying selection, leading to lineage integration and the long-term persistence of population structure within genetically cohesive species. Processes that drive the formation and maintenance of geographic genetic diversity while facilitating high rates of migration and limiting phenotypic differentiation may thereby result in population genetic structure that is not accompanied by reproductive isolation. We suggest that this framework can be applied more broadly to address the classic dilemma of "structure" versus "species" when evaluating phylogeographic diversity, unifying population genetics, species delimitation, and the underlying study of speciation. We demonstrate one such instance in the Seepage Salamander (Desmognathus aeneus) from the southeastern United States. Recent studies estimated up to 6.3% mitochondrial divergence and four phylogenomic lineages with broad admixture across geographic hybrid zones, which could potentially represent distinct species supported by our species-delimitation analyses. However, while limited dispersal promotes substantial isolation by distance, microhabitat specificity appears to yield stabilizing selection on a single, uniform, ecologically mediated phenotype. As a result, climatic cycles promote recurrent contact between lineages and repeated instances of high migration through time. Subsequent hybridization is apparently not counteracted by adaptive differentiation limiting introgression, leaving a single unified species with deeply divergent phylogeographic lineages that nonetheless do not appear to represent incipient species.
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Affiliation(s)
- R Alexander Pyron
- Department of Biological Sciences, The George Washington University, Washington, District of Columbia, USA
- Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, District of Columbia, USA
| | - Anvith Kakkera
- Thomas Jefferson High School for Science and Technology, Alexandria, Virginia, USA
| | - David A Beamer
- Office of Research, Economic Development and Engagement, East Carolina University, Greenville, North Carolina, USA
| | - Kyle A O'Connell
- Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, District of Columbia, USA
- Deloitte Consulting LLP, Health and Data AI, Arlington, Virginia, USA
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Lima-Rezende CA, Cabanne GS, Rocha AV, Carboni M, Zink RM, Caparroz R. A comparative phylogenomic analysis of birds reveals heterogeneous differentiation processes among Neotropical savannas. Mol Ecol 2022; 31:3451-3467. [PMID: 35510775 DOI: 10.1111/mec.16487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 03/25/2022] [Accepted: 04/11/2022] [Indexed: 11/30/2022]
Abstract
The main objective of this study is to evaluate biogeographic hypotheses of diversification and connection between isolated savannas north (Amazonian savannas) and south (Cerrado core) of the Amazon River. To achieve our goal, we employed genomic markers (genotyping-by-sequencing) to evaluate the genetic structure, population phylogenetic relationships, and historical range shifts of four Neotropical passerines with peri-Atlantic distributions: the Narrow-billed Woodcreeper (Lepidocolaptes angustirostris), the Plain-crested Elaenia (Elaenia cristata), the Grassland Sparrow (Ammodramus humeralis), and the White-banded Tanager (Neothraupis fasciata). The population genetic analyses indicated that landscape (e.g., geographic distance, landscape resistance, and percentage of tree cover) and climate metrics explained divergence among populations in most species, but without indicating a differential role between current and historical factors. Our results did not fully support the hypothesis that isolated populations at Amazonian savannas have been recently derived from the Cerrado core domain. Intraspecific phylogenies and gene flow analyses supported multiple routes of connection between the Cerrado and Amazonian savannas, rejecting the hypothesis that the Atlantic corridor explains the peri-Atlantic distribution. Our results reveal that the biogeographic history of the region is complex and cannot be explained by simple vicariant models.
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Affiliation(s)
- Cássia Alves Lima-Rezende
- División de Ornitología, Museo Argentino de Ciencias Naturales "Bernardino Rivadavia" - CONICET, Buenos Aires, Argentina
| | - Gustavo S Cabanne
- División de Ornitología, Museo Argentino de Ciencias Naturales "Bernardino Rivadavia" - CONICET, Buenos Aires, Argentina
| | - Amanda Vaz Rocha
- Instituto de Ciências Biológicas, Universidade de Brasília, Brasília, Brazil
| | - Martin Carboni
- División de Ornitología, Museo Argentino de Ciencias Naturales "Bernardino Rivadavia" - CONICET, Buenos Aires, Argentina
| | - Robert M Zink
- School of Natural Resources, School of Biological Sciences, and Nebraska State Museum, University of Nebraska-Lincoln, Lincoln, Nebraska, United States
| | - Renato Caparroz
- Instituto de Ciências Biológicas, Universidade de Brasília, Brasília, Brazil
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Dellinger AS, Paun O, Baar J, Temsch EM, Fernández-Fernández D, Schönenberger J. Population structure in Neotropical plants: integrating pollination biology, topography and climatic niches. Mol Ecol 2022; 31:2264-2280. [PMID: 35175652 PMCID: PMC9310734 DOI: 10.1111/mec.16403] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 02/10/2022] [Accepted: 02/11/2022] [Indexed: 11/29/2022]
Abstract
Animal pollinators mediate gene flow among plant populations, but in contrast to well‐studied topographic and (Pleistocene) environmental isolating barriers, their impact on population genetic differentiation remains largely unexplored. Comparing how these multifarious factors drive microevolutionary histories is, however, crucial for better resolving macroevolutionary patterns of plant diversification. Here we combined genomic analyses with landscape genetics and niche modelling across six related Neotropical plant species (424 individuals across 33 localities) differing in pollination strategy to test the hypothesis that highly mobile (vertebrate) pollinators more effectively link isolated localities than less mobile (bee) pollinators. We found consistently higher genetic differentiation (FST) among localities of bee‐ than vertebrate‐pollinated species with increasing geographical distance, topographic barriers and historical climatic instability. High admixture among montane populations further suggested relative climatic stability of Neotropical montane forests during the Pleistocene. Overall, our results indicate that pollinators may differentially impact the potential for allopatric speciation, thereby critically influencing diversification histories at macroevolutionary scales.
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Affiliation(s)
- Agnes S Dellinger
- Department of Botany and Biodiversity Research, University of Vienna, Austria.,Ecology and Evolutionary Biology, University of Colorado, Boulder, USA
| | - Ovidiu Paun
- Department of Botany and Biodiversity Research, University of Vienna, Austria
| | - Juliane Baar
- Department of Botany and Biodiversity Research, University of Vienna, Austria
| | - Eva M Temsch
- Department of Botany and Biodiversity Research, University of Vienna, Austria
| | | | - Jürg Schönenberger
- Department of Botany and Biodiversity Research, University of Vienna, Austria
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Uhrová M, Mikula O, Bennett NC, Van Daele P, Piálek L, Bryja J, Visser JH, Jansen van Vuuren B, Šumbera R. Species limits and phylogeographic structure in two genera of solitary African mole-rats Georychus and Heliophobius. Mol Phylogenet Evol 2021; 167:107337. [PMID: 34757170 DOI: 10.1016/j.ympev.2021.107337] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 10/19/2021] [Accepted: 10/27/2021] [Indexed: 11/28/2022]
Abstract
African mole-rats (Bathyergidae) are an intensively studied family of subterranean rodents including three highly social and three solitary genera. Although their phylogenetic interrelations are clear, genetic diversity and the number of species within each genus is much less certain. Among the solitary genera, Heliophobius and Georychus were for a long time considered as monotypic, but molecular studies demonstrated strong phylogeographic structure within each genus and proposed that they represent complexes of cryptic species. The present study re-evaluates their internal genetic/phylogenetic structure using a combination of methodological approaches. We generated datasets of one mitochondrial and six specifically selected nuclear markers as well as of a large number of double digest restriction site associated (ddRAD) loci and then applied species delimitation analyses based on the multispecies coalescent model or clustering on co-ancestry matrices. The population structure was largely congruent across all analyses, but the methods differed in their resolution scale when determining distinct gene pools. While the multispecies coalescent model distinguished five Georychus and between eleven to thirteen Heliophobius gene pools in both Sanger sequenced and ddRAD loci, two clustering algorithms revealed significantly finer or coarser structure in ddRAD based co-ancestry matrices. Tens of clusters were distinguished by fineRADstructure and one (in Georychus) or two clusters (in Heliophobius) by Infomap. The divergence dating of the bathyergid phylogeny estimated that diversification within both genera coincided with the onset of the Pleistocene and was likely driven by repeated large-scale climatic changes. Based on this updated genetic evidence, we suggest recognizing one species of Georychus and two species of Heliophobius, corresponding to a northern and southern major lineage, separated by the Eastern Arc Mountains. Yet, the final taxonomic revision should await integrated evidence stemming from e.g.. morphological, ecological, or behavioral datasets.
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Affiliation(s)
- M Uhrová
- Department of Zoology, Faculty of Sciences, University of South Bohemia
| | - O Mikula
- Department of Zoology, Faculty of Sciences, University of South Bohemia; Institute of Vertebrate Biology, Czech Academy of Sciences
| | - N C Bennett
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, 0002, South Africa
| | - P Van Daele
- Department of Zoology, Faculty of Sciences, University of South Bohemia
| | - L Piálek
- Department of Zoology, Faculty of Sciences, University of South Bohemia
| | - J Bryja
- Institute of Vertebrate Biology, Czech Academy of Sciences
| | - J H Visser
- Centre for Ecological Genomics and Wildlife Conservation, Department of Zoology, University of Johannesburg, Auckland Park, Johannesburg, South Africa; Department of Conservation and Marine Sciences, Cape Peninsula University of Technology, P.O. Box 652, Cape Town 8000, South Africa
| | - B Jansen van Vuuren
- Centre for Ecological Genomics and Wildlife Conservation, Department of Zoology, University of Johannesburg, Auckland Park, Johannesburg, South Africa
| | - R Šumbera
- Department of Zoology, Faculty of Sciences, University of South Bohemia
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Pérez F, Hinojosa LF, Peralta G, Montenegro P, Irarrázabal C, Cossio M. Genetic Patterns of Myrceugenia correifolia, a Rare Species of Fog-Dependent Forests of Mediterranean Chile: Is It a Climatic Relict? Front Plant Sci 2017; 8:1097. [PMID: 28729869 PMCID: PMC5498513 DOI: 10.3389/fpls.2017.01097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 06/06/2017] [Indexed: 06/07/2023]
Abstract
Rare species frequently occur in areas with microclimatic conditions that are atypical for their regions, but that were more common in the past, and that probably have operated as climatic refugia for a long time. Myrceugenia correifolia is a rare arboreal species that grows in deep canyons and hilltops of the Coast Range of north-central Chile between 30° and 35°S. In the northern edge of its distribution M. correifolia grows in small patches of fog-dependent forest surrounding by xeric vegetation. These forest formations are thought to be remnants of an ancient and continuous rainforest that according to some authors became fragmented during aridization of the Neogene (Neogene relict) and to others during warm-dry cycles of the Pleistocene (glacial relicts). Here we asked whether the northernmost populations of M. correifolia are Neogene relicts, glacial relicts, or the result of a recent northward colonization. To answer this question we examined genetic diversity and population divergence of M. correifolia using microsatellite markers, tested various competing population history scenarios with an approximate Bayesian computation (ABC) method, and complemented these data with ecological niche modeling (ENM). We detected three genetic clusters with a distinctive latitudinal pattern (north, center, and south) and high levels of differentiation (FST = 0.36). Demographic inference supported an admixture event 31 kya between two populations that diverged from an ancient population 139 kya. The admixture time coincides with the beginning of a period of wet conditions in north-central Chile that extended from 33 to 19 kya and was preceded by dry and cold conditions. These results suggest that increased precipitation during glacial periods triggered northward expansion of the range of M. correifolia, with subsequent admixture between populations that remained separated during interglacial periods. Accordingly, ENM models showed that suitable habitats for M. correifolia in north-central Chile were larger and less fragmented during the Last Glacial Maximum than at present, suggesting that northernmost populations of this species are glacial relicts.
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Affiliation(s)
- Fernanda Pérez
- Departamento de Ecología, Pontificia Universidad Católica de ChileSantiago, Chile
- Institute of Ecology and BiodiversitySantiago, Chile
| | - Luis F. Hinojosa
- Institute of Ecology and BiodiversitySantiago, Chile
- Departamento de Ciencias Ecológicas, Universidad de ChileSantiago, Chile
| | - Gioconda Peralta
- Departamento de Ecología, Pontificia Universidad Católica de ChileSantiago, Chile
| | - Paz Montenegro
- Departamento de Ciencias Ecológicas, Universidad de ChileSantiago, Chile
| | - Carla Irarrázabal
- Departamento de Ecología, Pontificia Universidad Católica de ChileSantiago, Chile
| | - Michel Cossio
- Departamento de Ecología, Pontificia Universidad Católica de ChileSantiago, Chile
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