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Kazilas C, Dufresnes C, France J, Kalaentzis K, Martínez-Solano I, de Visser MC, Arntzen JW, Wielstra B. Spatial genetic structure in European marbled newts revealed with target enrichment by sequence capture. Mol Phylogenet Evol 2024; 194:108043. [PMID: 38382821 DOI: 10.1016/j.ympev.2024.108043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 12/21/2023] [Accepted: 02/18/2024] [Indexed: 02/23/2024]
Abstract
European marbled newts come in two species that have abutting ranges. The northern species, Triturus marmoratus, is found in France and the northern part of the Iberian Peninsula, whereas the southern species, T. pygmaeus, is found in the southwestern corner of the Iberian Peninsula. We study the intraspecific genetic differentiation of the group because morphological data show geographical variation and because the Iberian Peninsula is a recognized center of speciation and intraspecific genetic diversity for all kinds of organisms, amphibians included. We use target enrichment by sequence capture to generate c. 7 k nuclear DNA markers. We observe limited genetic exchange between the species, which confirms their distinctiveness. Both species show substantial genetic structuring that is only in part mirrored by morphological variation. Genetically differentiated groups are found in the south (T. marmoratus) and west (T. pygmaeus) of the species ranges. Our observations highlight the position of the Iberian Peninsula as a hotspot for genetic differentiation.
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Affiliation(s)
- Christos Kazilas
- Naturalis Biodiversity Center, P.O. Box 9517, 2300 RA Leiden, The Netherlands; Institute of Biology Leiden, Leiden University, P.O. Box 9505, 2300 RA Leiden, The Netherlands.
| | - Christophe Dufresnes
- LASER, College of Biology and the Environment, Nanjing Forestry University, Nanjing, People's Republic of China; Institut de Systématique, Evolution, Biodiversité (ISYEB), Muséum national d'Histoire naturelle, CNRS, Sorbonne Université, EPHE, Université des Antilles, Paris, France
| | - James France
- Naturalis Biodiversity Center, P.O. Box 9517, 2300 RA Leiden, The Netherlands; Institute of Biology Leiden, Leiden University, P.O. Box 9505, 2300 RA Leiden, The Netherlands
| | - Konstantinos Kalaentzis
- Naturalis Biodiversity Center, P.O. Box 9517, 2300 RA Leiden, The Netherlands; Institute of Biology Leiden, Leiden University, P.O. Box 9505, 2300 RA Leiden, The Netherlands
| | - Iñigo Martínez-Solano
- Museo Nacional de Ciencias Naturales, MNCN-CSIC, c/ José Gutiérrez Abascal 2, 28006 Madrid, Spain
| | - Manon C de Visser
- Naturalis Biodiversity Center, P.O. Box 9517, 2300 RA Leiden, The Netherlands; Institute of Biology Leiden, Leiden University, P.O. Box 9505, 2300 RA Leiden, The Netherlands
| | - Jan W Arntzen
- Naturalis Biodiversity Center, P.O. Box 9517, 2300 RA Leiden, The Netherlands; Institute of Biology Leiden, Leiden University, P.O. Box 9505, 2300 RA Leiden, The Netherlands
| | - Ben Wielstra
- Naturalis Biodiversity Center, P.O. Box 9517, 2300 RA Leiden, The Netherlands; Institute of Biology Leiden, Leiden University, P.O. Box 9505, 2300 RA Leiden, The Netherlands
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2
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Fukutani K, Matsui M, Nishikawa K. Population genetic structure and hybrid zone analyses for species delimitation in the Japanese toad ( Bufo japonicus). PeerJ 2023; 11:e16302. [PMID: 37901459 PMCID: PMC10607272 DOI: 10.7717/peerj.16302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Accepted: 09/25/2023] [Indexed: 10/31/2023] Open
Abstract
Hybridization following secondary contact may produce different outcomes depending on the extent to which genetic diversity and reproductive barriers have accumulated during isolation. The Japanese toad, Bufo japonicus, is distributed on the main islands of Japan. In the present study, we applied multiplexed inter-simple sequence repeat genotyping by sequencing to achieve the fine-scale resolution of the genetic cluster in B. j. japonicus and B. j. formosus. We also elucidated hybridization patterns and gene flow degrees across contact zones between the clusters identified. Using SNP data, we found four genetic clusters in B. j. japonicus and B. j. formosus and three contact zones of the cluster pairs among these four clusters. The two oldest diverged lineages, B. j. japonicus and B. j. formosus, formed a narrow contact zone consistent with species distinctiveness. Therefore, we recommend that these two subspecies be elevated to the species level. In contrast, the less diverged pairs of two clusters in B. j. japonicus and B. j. formosus, respectively, admixed over a hundred kilometers, suggesting that they have not yet developed strong reproductive isolation and need to be treated as conspecifics. These results will contribute to resolving taxonomic confusion in Japanese toads.
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Affiliation(s)
- Kazumi Fukutani
- Graduate School of Human and Environmental Studies, Kyoto University, Kyoto, Japan
| | - Masafumi Matsui
- Graduate School of Human and Environmental Studies, Kyoto University, Kyoto, Japan
| | - Kanto Nishikawa
- Graduate School of Human and Environmental Studies, Kyoto University, Kyoto, Japan
- Graduate School of Global Environmental Studies, Kyoto University, Kyoto, Japan
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3
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Preckler-Quisquater S, Kierepka EM, Reding DM, Piaggio AJ, Sacks BN. Can demographic histories explain long-term isolation and recent pulses of asymmetric gene flow between highly divergent grey fox lineages? Mol Ecol 2023; 32:5323-5337. [PMID: 37632719 DOI: 10.1111/mec.17105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 08/01/2023] [Accepted: 08/09/2023] [Indexed: 08/28/2023]
Abstract
Secondary contact zones between deeply divergent, yet interfertile, lineages provide windows into the speciation process. North American grey foxes (Urocyon cinereoargenteus) are divided into western and eastern lineages that diverged approximately 1 million years ago. These ancient lineages currently hybridize in a relatively narrow zone of contact in the southern Great Plains, a pattern more commonly observed in smaller-bodied taxa, which suggests relatively recent contact after a long period of allopatry. Based on local ancestry inference with whole-genome sequencing (n = 43), we identified two distinct Holocene pulses of admixture. The older pulse (500-3500 YBP) reflected unidirectional gene flow from east to west, whereas the more recent pulse (70-200 YBP) of admixture was bi-directional. Augmented with genotyping-by-sequencing data from 216 additional foxes, demographic analyses indicated that the eastern lineage declined precipitously after divergence, remaining small throughout most of the late Pleistocene, and expanding only during the Holocene. Genetic diversity in the eastern lineage was highest in the southeast and lowest near the contact zone, consistent with a westward expansion. Concordantly, distribution modelling indicated that during their isolation, the most suitable habitat occurred far east of today's contact zone or west of the Great Plains. Thus, long-term isolation was likely caused by the small, distant location of the eastern refugium, with recent contact reflecting a large increase in suitable habitat and corresponding demographic expansion from the eastern refugium. Ultimately, long-term isolation in grey foxes may reflect their specialized bio-climatic niche. This system presents an opportunity for future investigation of potential pre- and post-zygotic isolating mechanisms.
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Affiliation(s)
- Sophie Preckler-Quisquater
- Mammalian Ecology and Conservation Unit, Veterinary Genetics Laboratory, School of Veterinary Medicine, University of California, Davis, California, USA
| | - Elizabeth M Kierepka
- North Carolina Museum of Natural Sciences, Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, North Carolina, USA
| | - Dawn M Reding
- Department of Biology, Luther College, Decorah, Iowa, USA
| | - Antoinette J Piaggio
- USDA, Wildlife Services, National Wildlife Research Center, Wildlife Genetics Lab, Fort Collins, Colorado, USA
| | - Benjamin N Sacks
- Mammalian Ecology and Conservation Unit, Veterinary Genetics Laboratory, School of Veterinary Medicine, University of California, Davis, California, USA
- Department of Population Health and Reproduction, School of Veterinary Medicine, University of California, Davis, California, USA
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4
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van Riemsdijk I, Arntzen JW, Bucciarelli GM, McCartney-Melstad E, Rafajlović M, Scott PA, Toffelmier E, Shaffer HB, Wielstra B. Two transects reveal remarkable variation in gene flow on opposite ends of a European toad hybrid zone. Heredity (Edinb) 2023; 131:15-24. [PMID: 37106116 PMCID: PMC10313803 DOI: 10.1038/s41437-023-00617-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 03/27/2023] [Accepted: 04/12/2023] [Indexed: 04/29/2023] Open
Abstract
Speciation entails a reduction in gene flow between lineages. The rates at which genomic regions become isolated varies across space and time. Barrier markers are linked to putative genes involved in (processes of) reproductive isolation, and, when observed over two transects, indicate species-wide processes. In contrast, transect-specific putative barrier markers suggest local processes. We studied two widely separated transects along the 900 km hybrid zone between Bufo bufo and B. spinosus, in northern and southern France, for ~1200 RADseq markers. We used genomic and geographic cline analyses to identify barrier markers based on their restricted introgression, and found that some markers are transect-specific, while others are shared between transects. Twenty-six barrier markers were shared across both transects, of which some are clustered in the same chromosomal region, suggesting that their associated genes are involved in reduced gene flow across the entire hybrid zone. Transect-specific barrier markers were twice as numerous in the southern than in the northern transect, suggesting that the overall barrier effect is weaker in northern France. We hypothesize that this is consistent with a longer period of secondary contact in southern France. The smaller number of introgressed genes in the northern transect shows considerably more gene flow towards the southern (B. spinosus) than the northern species (B. bufo). We hypothesize that hybrid zone movement in northern France and hybrid zone stability in southern France explain this pattern. The Bufo hybrid zone provides an excellent opportunity to separate a general barrier effect from localized gene flow-reducing conditions.
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Affiliation(s)
- I van Riemsdijk
- Naturalis Biodiversity Center, Leiden, the Netherlands.
- Institute of Biology Leiden, Leiden University, Leiden, the Netherlands.
- Institute for Evolution and Ecology, Plant Evolutionary Ecology, Tübingen University, Tübingen, Germany.
| | - J W Arntzen
- Naturalis Biodiversity Center, Leiden, the Netherlands
- Institute of Biology Leiden, Leiden University, Leiden, the Netherlands
| | - G M Bucciarelli
- Department of Ecology and Evolutionary Biology, UCLA, Los Angeles, CA, USA
- La Kretz Center for California Conservation Science, Institute of the Environment and Sustainability, UCLA, Los Angeles, CA, USA
- Institute of the Environment, UC Davis, Davis, CA, USA
- Department of Wildlife, Fish, and Conservation Biology, UC Davis, Davis, CA, USA
| | - E McCartney-Melstad
- Department of Ecology and Evolutionary Biology, UCLA, Los Angeles, CA, USA
- La Kretz Center for California Conservation Science, Institute of the Environment and Sustainability, UCLA, Los Angeles, CA, USA
| | - M Rafajlović
- Department of Marine Sciences, University of Gothenburg, Gothenburg, Sweden
- The Linnaeus Centre for Marine Evolutionary Biology, University of Gothenburg, Gothenburg, Sweden
| | - P A Scott
- Department of Ecology and Evolutionary Biology, UCLA, Los Angeles, CA, USA
- Natural Sciences Collegium, Eckerd College, 4200 54 Ave S, St Petersburg, FL, 33711, USA
| | - E Toffelmier
- Department of Ecology and Evolutionary Biology, UCLA, Los Angeles, CA, USA
- La Kretz Center for California Conservation Science, Institute of the Environment and Sustainability, UCLA, Los Angeles, CA, USA
| | - H B Shaffer
- Department of Ecology and Evolutionary Biology, UCLA, Los Angeles, CA, USA
- La Kretz Center for California Conservation Science, Institute of the Environment and Sustainability, UCLA, Los Angeles, CA, USA
| | - B Wielstra
- Naturalis Biodiversity Center, Leiden, the Netherlands
- Institute of Biology Leiden, Leiden University, Leiden, the Netherlands
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5
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Dursun C, Özdemir N, Gül S. Easternmost distribution of Bufo bufo (Linnaeus, 1758) in Türkiye: implications for the putative contact zone between B. bufo and B. verrucosissimus. Genetica 2023; 151:11-27. [PMID: 36418607 DOI: 10.1007/s10709-022-00175-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2022] [Accepted: 11/09/2022] [Indexed: 11/25/2022]
Abstract
The geographic range of a species is crucial for obtaining information on the exact distribution of the species. The geographic data are important for delimiting distinct species or exploring the degree of differentiation among different populations of a species. The local details of species boundaries facilitate the study of the importance of phylogeographic background, secondary contacts, and hybrid zones, along with the relations between the species and its extrinsic environmental factors. In the present study, the range boundaries of Bufo bufo and Bufo verrucosissimus in the north-eastern region of Türkiye were delineated using an integrative taxonomic approach that utilized a combination of molecular and morphological data. According to the mtDNA results of the present study, B. bufo inhabits a single distribution from İyidere town to Çayeli town in Rize, while B. verrucosissimus is distributed from Şavşat town of Artvin to Ardeşen town in Rize. In addition, the two species coexist in Pazar, Hemşin, and Çamlıhemşin towns in Rize. The demographic analyses indicated a distinct population expansion for the B. verrucosissimus species after the Last Glacial Maximum, while the same did not occur for B. bufo. The univariate and multivariate statistical analyses conducted for the morphological data of the two species corroborated the presence of a putative contact zone between B. bufo and B. verrucosissimus. In summary, the present study resolved the non-distinct geographic boundaries between B. bufo and B. verrucosissimus species and also revealed the easternmost distribution of B. bufo in Türkiye. In addition, important evidence on the putative contact zone between the two species was indicated using an integrative taxonomic approach.
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Affiliation(s)
- Cantekin Dursun
- Department of Biology, Faculty of Arts and Sciences, Recep Tayyip Erdogan University, Fener Mah., 53100, Rize, Turkey.
| | - Nurhayat Özdemir
- Department of Biology, Faculty of Arts and Sciences, Recep Tayyip Erdogan University, Fener Mah., 53100, Rize, Turkey
| | - Serkan Gül
- Department of Biology, Faculty of Arts and Sciences, Recep Tayyip Erdogan University, Fener Mah., 53100, Rize, Turkey
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Rivera D, Prates I, Caldwell JP, Rodrigues MT, Fujita MK. Testing assertions of widespread introgressive hybridization in a clade of neotropical toads with low mate selectivity (Rhinella granulosa species group). Heredity (Edinb) 2023; 130:14-21. [PMID: 36333595 DOI: 10.1038/s41437-022-00571-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 10/20/2022] [Accepted: 10/21/2022] [Indexed: 11/06/2022] Open
Abstract
Discordance between different genomic regions, often identified through multilocus sequencing of selected markers, presents particular difficulties in identifying historical processes which drive species diversity and boundaries. Mechanisms causing discordance, such as incomplete lineage sorting or introgression due to interspecific hybridization, are better identified based on population-level genomic datasets. In the toads of the Rhinella granulosa species group, patterns of mito-nuclear discordance and potential hybridization have been reported by several studies. However, these patterns were proposed based on few loci, such that alternative mechanisms behind gene-tree heterogeneity cannot be ruled out. Using genome-wide ddRADseq loci from a subset of species within this clade, we found only partial concordance between currently recognized species-level taxon boundaries and patterns of genetic structure. While most taxa within the R. granulosa group correspond to clades, genetic clustering analyses sometimes grouped distinct taxonomic units into a single cluster. Moreover, levels of admixture between inferred clusters were limited and restricted to a single taxon pair which is best explained by incomplete lineage sorting as opposed to introgressive hybridization, according to D-statistics results. These findings contradict previous assertions of widespread cryptic diversity and gene flow within the R. granulosa clade. Lastly, our analyses suggest that diversification events within the Rhinella granulosa group mostly dated back to the early Pliocene, being generally younger than species divergences in other closely related clades that present high levels of cross-species gene flow. This finding uniquely contradicts common assertions that this young clade of toads exhibits interspecific hybridization.
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Affiliation(s)
- Danielle Rivera
- Department of Applied Ecology, North Carolina State University, Raleigh, NC, USA. .,Amphibian and Reptile Diversity Research Center, University of Texas at Arlington, Arlington, TX, USA.
| | - Ivan Prates
- Department of Ecology and Evolutionary Biology and Museum of Zoology, University of Michigan, Ann Arbor, MI, USA
| | - Janalee P Caldwell
- Sam Noble Museum and Department of Biology, University of Oklahoma, Norman, OK, USA
| | - Miguel Trefaut Rodrigues
- Departamento de Zoologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Matthew K Fujita
- Amphibian and Reptile Diversity Research Center, University of Texas at Arlington, Arlington, TX, USA.,Department of Biology and Amphibian and Reptile Diversity Research Center, University of Texas at Arlington, Arlington, TX, USA
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7
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Mandeville EG, Hall RO, Buerkle CA. Ecological outcomes of hybridization vary extensively in Catostomus fishes. Evolution 2022; 76:2697-2711. [PMID: 36097356 PMCID: PMC9801484 DOI: 10.1111/evo.14624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 07/20/2022] [Accepted: 07/26/2022] [Indexed: 01/22/2023]
Abstract
Hybridization outcomes vary geographically and can depend on the environment. Hybridization can also reshape biotic interactions, leading to ecological shifts. If hybrids function differently ecologically in ways that enhance or reduce fitness, and those ecological roles vary geographically, ecological factors might explain variation in hybridization outcomes. However, relatively few studies have focused on ecological traits of hybrids. We compared the feeding ecology of Catostomus fish species and hybrids by using stable isotopes (δ13 C and δ15 N) as a proxy for diet and habitat use, and compared two native species, an introduced species, and three interspecific hybrid crosses. We included hybrids and parental species from seven rivers where hybridization outcomes vary. Relative isotopic niches of native species varied geographically, but native species did not fully overlap in isotopic space in any river sampled, suggesting little overlap of resource use between historically sympatric species. The introduced species overlapped with one or both native species in every river, suggesting similar resource use and potential competition. Hybrids occupied intermediate, matching, or more transgressive isotopic niches, and varied within and among rivers. Ecological outcomes of hybridization varied across locations, implying that hybridization might have unpredictable, idiosyncratic ecological effects.
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Affiliation(s)
- Elizabeth G. Mandeville
- Department of Integrative Biology, University of Guelph, Guelph, Ontario Canada
- Department of Botany, University of Wyoming, Laramie, Wyoming USA
- Program in Ecology, University of Wyoming, Laramie, Wyoming USA
| | - Robert O. Hall
- Program in Ecology, University of Wyoming, Laramie, Wyoming USA
- Flathead Lake Biological Station, University of Montana, Polson, Montana USA (present address)
- Department of Zoology and Physiology, University of Wyoming, Laramie, Wyoming USA
| | - C. Alex Buerkle
- Department of Botany, University of Wyoming, Laramie, Wyoming USA
- Program in Ecology, University of Wyoming, Laramie, Wyoming USA
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8
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Dufresnes C, Crochet PA. Sex chromosomes as supergenes of speciation: why amphibians defy the rules? Philos Trans R Soc Lond B Biol Sci 2022; 377:20210202. [PMID: 35694748 PMCID: PMC9189495 DOI: 10.1098/rstb.2021.0202] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
As reflected by the two rules of speciation (Haldane's rule and the large X-/Z-effect), sex chromosomes are expected to behave like supergenes of speciation: they recombine only in one sex (XX females or ZZ males), supposedly recruit sexually antagonistic genes and evolve faster than autosomes, which can all contribute to pre-zygotic and post-zygotic isolation. While this has been mainly studied in organisms with conserved sex-determining systems and highly differentiated (heteromorphic) sex chromosomes like mammals, birds and some insects, these expectations are less clear in organismal groups where sex chromosomes repeatedly change and remain mostly homomorphic, like amphibians. In this article, we review the proposed roles of sex-linked genes in isolating nascent lineages throughout the speciation continuum and discuss their support in amphibians given current knowledge of sex chromosome evolution and speciation modes. Given their frequent recombination and lack of differentiation, we argue that amphibian sex chromosomes are not expected to become supergenes of speciation, which is reflected by the rarity of empirical studies consistent with a 'large sex chromosome effect' in frogs and toads. The diversity of sex chromosome systems in amphibians has a high potential to disentangle the evolutionary mechanisms responsible for the emergence of sex-linked speciation genes in other organisms. This article is part of the theme issue 'Genomic architecture of supergenes: causes and evolutionary consequences'.
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Affiliation(s)
- Christophe Dufresnes
- LASER, College of Biology and Environment, Nanjing Forestry University, Nanjing 210037, People's Republic of China
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9
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MacPherson A, Wang S, Yamaguchi R, Rieseberg L, Otto S. Parental Population Range Expansion Before Secondary Contact Promotes Heterosis. Am Nat 2022; 200:E1-E15. [DOI: 10.1086/719656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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10
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Sequeira F, Arntzen JW, van Gulik D, Hajema S, Diaz RL, Wagt M, van Riemsdijk I. Genetic traces of hybrid zone movement across a fragmented habitat. J Evol Biol 2022; 35:400-412. [PMID: 35043504 DOI: 10.1111/jeb.13982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 01/06/2022] [Accepted: 01/07/2022] [Indexed: 11/27/2022]
Abstract
Theoretical and empirical studies suggest that the structure and position of hybrid zones can change over time. Evidence for moving hybrid zones has been directly inferred by repeated sampling over time, or indirectly through the detection of genetic footprints left by the receding species and the resulting asymmetric patterns of introgression across markers. We here investigate a hybrid zone formed by two subspecies of the Iberian golden-striped salamander, Chioglossa lusitanica, using a panel of 35 nuclear loci (31 SNPs and 4 allozymes) and one mitochondrial locus in a transect in central Portugal. We found concordant and coincident clines for most of the nuclear loci (n=22, 63%), defining a narrow hybrid zone of ca. 6 km wide, with the centre positioned ca. 15 km south of the Mondego river. Asymmetric introgression was observed at another 14 loci. Their clines are displaced towards the north, with positions located either close to the Mondego river (n=6), or further northwards (n=8). We interpret these profiles as genetic traces of the southward displacement of C. lusitanica lusitanica by C. l. longipes over the wider Mondego river valley. We noted the absence of significant linkage disequilibrium and we inferred low levels of effective selection per locus against hybrids, suggesting that introgression in the area of species replacement occurred under a neutral diffusion process. A species distribution model suggests that the C. lusitanica hybrid zone coincides with a narrow corridor of fragmented habitat. From the position of the displaced clines, we infer that patches of locally suitable habitat trapped some genetic variants that became disassociated from the southward moving hybrid zone. This study highlights the influence of habitat availability on hybrid zone movement.
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Affiliation(s)
- Fernando Sequeira
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO Laboratório Associado, Universidade do Porto, Campus de Vairão, 4485-661, Vairão, Portugal.,BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Campus de Vairão, 4485-661, Vairão, Portugal
| | - Jan W Arntzen
- Institute of Biology, Leiden University, Leiden, The Netherlands.,Naturalis Biodiversity Centre, P. O. Box 9517, 2300 RA, Leiden, The Netherlands
| | - Davy van Gulik
- Hogeschool Leiden, P. O. Box 382, 2300 AJ, Leiden, The Netherlands
| | - Steven Hajema
- Hogeschool Leiden, P. O. Box 382, 2300 AJ, Leiden, The Netherlands
| | - Ruben Lopez Diaz
- Hogeschool Leiden, P. O. Box 382, 2300 AJ, Leiden, The Netherlands
| | - Mattijn Wagt
- Hogeschool Leiden, P. O. Box 382, 2300 AJ, Leiden, The Netherlands
| | - Isolde van Riemsdijk
- Naturalis Biodiversity Centre, P. O. Box 9517, 2300 RA, Leiden, The Netherlands.,Hogeschool Leiden, P. O. Box 382, 2300 AJ, Leiden, The Netherlands
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11
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Wolfgramm H, Martens J, Töpfer T, Vamberger M, Pathak A, Stuckas H, Päckert M. Asymmetric allelic introgression across a hybrid zone of the coal tit ( Periparus ater) in the central Himalayas. Ecol Evol 2021; 11:17332-17351. [PMID: 34938512 PMCID: PMC8668783 DOI: 10.1002/ece3.8369] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 10/26/2021] [Accepted: 11/02/2021] [Indexed: 11/07/2022] Open
Abstract
In the Himalayas, a number of secondary contact zones have been described for vicariant vertebrate taxa. However, analyses of genetic divergence and admixture are missing for most of these examples. In this study, we provide a population genetic analysis for the coal tit (Periparus ater) hybrid zone in Nepal. Intermediate phenotypes between the distinctive western "spot-winged tit" (P. a. melanolophus) and Eastern Himalayan coal tits (P. a. aemodius) occur across a narrow range of <100 km in western Nepal. As a peculiarity, another distinctive cinnamon-bellied form is known from a single population so far. Genetic admixture of western and eastern mitochondrial lineages was restricted to the narrow zone of phenotypically intermediate populations. The cline width was estimated 46 km only with a center close to the population of the cinnamon-bellied phenotype. In contrast, allelic introgression of microsatellite loci was asymmetrical from eastern P. a. aemodius into far western populations of phenotypic P. a. melanolophus but not vice versa. Accordingly, the microsatellite cline was about 3.7 times wider than the mitochondrial one.
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Affiliation(s)
- Hannes Wolfgramm
- Senckenberg Natural History Collections DresdenDresdenGermany
- Present address:
Department of Functional GenomicsInterfaculty Institute of Genetics and Functional GenomicsUniversity Medicine GreifswaldGreifswaldGermany
| | - Jochen Martens
- Institute of Organismic and Molecular Evolution (iomE)Johannes Gutenberg UniversityMainzGermany
| | - Till Töpfer
- Leibniz Institute for the Analysis of Biodiversity ChangeZoological Research Museum Alexander KoenigBonnGermany
| | | | - Abhinaya Pathak
- Department of National Parks and Wildlife ConservationKathmanduNepal
| | - Heiko Stuckas
- Senckenberg Natural History Collections DresdenDresdenGermany
| | - Martin Päckert
- Senckenberg Natural History Collections DresdenDresdenGermany
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12
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Zheng W, Yan LJ, Burgess KS, Luo YH, Zou JY, Qin HT, Wang JH, Gao LM. Natural hybridization among three Rhododendron species (Ericaceae) revealed by morphological and genomic evidence. BMC PLANT BIOLOGY 2021; 21:529. [PMID: 34763662 PMCID: PMC8582147 DOI: 10.1186/s12870-021-03312-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Accepted: 11/02/2021] [Indexed: 06/08/2023]
Abstract
BACKGROUND Natural hybridization can influence the adaptive response to selection and accelerate species diversification. Understanding the composition and structure of hybrid zones may elucidate patterns of hybridization processes that are important to the formation and maintenance of species, especially for taxa that have experienced rapidly adaptive radiation. Here, we used morphological traits, ddRAD-seq and plastid DNA sequence data to investigate the structure of a Rhododendron hybrid zone and uncover the hybridization patterns among three sympatric and closely related species. RESULTS Our results show that the hybrid zone is complex, where bi-directional hybridization takes place among the three sympatric parental species: R. spinuliferum, R. scabrifolium, and R. spiciferum. Hybrids between R. spinuliferum and R. spiciferum (R. ×duclouxii) comprise multiple hybrid classes and a high proportion of F1 generation hybrids, while a novel hybrid taxon between R. spinuliferum and R. scabrifolium dominated the F2 generation, but no backcross individuals were detected. The hybrid zone showed basically coincident patterns of population structure between genomic and morphological data. CONCLUSIONS Natural hybridization exists among the three Rhododendron species in the hybrid zone, although patterns of hybrid formation vary between hybrid taxa, which may result in different evolutionary outcomes. This study represents a unique opportunity to dissect the ecological and evolutionary mechanisms associated with adaptive radiation of Rhododendron species in a biodiversity hotspot.
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Affiliation(s)
- Wei Zheng
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, 650201, Kunming, Yunnan, China
- University of Chinese Academy of Sciences, 10049, Beijing, China
| | - Li-Jun Yan
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, 650201, Kunming, Yunnan, China
- University of Chinese Academy of Sciences, 10049, Beijing, China
- College of Vocational and Technical Education, Yunnan Normal University, 650092, Kunming, Yunnan, China
| | - Kevin S Burgess
- Department of Biology, Columbus State University, University System of Georgia, 31907-5645, Columbus, GA, USA
| | - Ya-Huang Luo
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, 650201, Kunming, Yunnan, China
| | - Jia-Yun Zou
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, 650201, Kunming, Yunnan, China
- University of Chinese Academy of Sciences, 10049, Beijing, China
| | - Han-Tao Qin
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, 650201, Kunming, Yunnan, China
- University of Chinese Academy of Sciences, 10049, Beijing, China
| | - Ji-Hua Wang
- The Flower Research Institute, Yunnan Academy of Agricultural Sciences, 650205, Kunming, China.
| | - Lian-Ming Gao
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, 650201, Kunming, Yunnan, China.
- Lijiang Forest Biodiversity National Observation and Research Station, Kunming Institute of Botany, Chinese Academy of Sciences, 674100, Lijiang, Yunnan, China.
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13
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Velo-Antón G, Lourenço A, Galán P, Nicieza A, Tarroso P. Landscape resistance constrains hybridization across contact zones in a reproductively and morphologically polymorphic salamander. Sci Rep 2021; 11:9259. [PMID: 33927228 PMCID: PMC8085075 DOI: 10.1038/s41598-021-88349-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 04/07/2021] [Indexed: 02/02/2023] Open
Abstract
Explicitly accounting for phenotypic differentiation together with environmental heterogeneity is crucial to understand the evolutionary dynamics in hybrid zones. Species showing intra-specific variation in phenotypic traits that meet across environmentally heterogeneous regions constitute excellent natural settings to study the role of phenotypic differentiation and environmental factors in shaping the spatial extent and patterns of admixture in hybrid zones. We studied three environmentally distinct contact zones where morphologically and reproductively divergent subspecies of Salamandra salamandra co-occur: the pueriparous S. s. bernardezi that is mostly parapatric to its three larviparous subspecies neighbours. We used a landscape genetics framework to: (i) characterise the spatial location and extent of each contact zone; (ii) assess patterns of introgression and hybridization between subspecies pairs; and (iii) examine the role of environmental heterogeneity in the evolutionary dynamics of hybrid zones. We found high levels of introgression between parity modes, and between distinct phenotypes, thus demonstrating the evolution to pueriparity alone or morphological differentiation do not lead to reproductive isolation between these highly divergent S. salamandra morphotypes. However, we detected substantial variation in patterns of hybridization across contact zones, being lower in the contact zone located on a topographically complex area. We highlight the importance of accounting for spatial environmental heterogeneity when studying evolutionary dynamics of hybrid zones.
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Affiliation(s)
- Guillermo Velo-Antón
- grid.5808.50000 0001 1503 7226CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos da Universidade do Porto, Instituto de Ciências Agrárias de Vairão. R. Padre Armando Quintas, 4485-661 Vairão, Portugal ,grid.6312.60000 0001 2097 6738Universidade de Vigo, Grupo de Ecoloxía Animal, Departamento de Ecoloxía e Bioloxía Animal, Torre Cacti (Lab 97), 36310 Vigo, Spain
| | - André Lourenço
- grid.5808.50000 0001 1503 7226CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos da Universidade do Porto, Instituto de Ciências Agrárias de Vairão. R. Padre Armando Quintas, 4485-661 Vairão, Portugal ,grid.5808.50000 0001 1503 7226Departamento de Biologia da Faculdade de Ciências, Universidade do Porto. Rua Campo Alegre, 4169-007 Porto, Portugal
| | - Pedro Galán
- grid.8073.c0000 0001 2176 8535Grupo de Investigación en Bioloxía Evolutiva (GIBE), Departamento de Bioloxía, Facultade de Ciencias, Universidade da Coruña, Campus da Zapateira, s/n, 15071 A Coruña, Spain
| | - Alfredo Nicieza
- grid.10863.3c0000 0001 2164 6351Departamento de Biologıa de Organismos y Sistemas, Universidad de Oviedo, Oviedo, Spain ,grid.10863.3c0000 0001 2164 6351Unidad Mixta de Investigacion en Biodiversidad (UMIB), CSIC-Universidad de Oviedo-Principado de Asturias, Mieres, Spain
| | - Pedro Tarroso
- grid.5808.50000 0001 1503 7226CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos da Universidade do Porto, Instituto de Ciências Agrárias de Vairão. R. Padre Armando Quintas, 4485-661 Vairão, Portugal
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14
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Chiocchio A, Arntzen JW, Martínez-Solano I, de Vries W, Bisconti R, Pezzarossa A, Maiorano L, Canestrelli D. Reconstructing hotspots of genetic diversity from glacial refugia and subsequent dispersal in Italian common toads (Bufo bufo). Sci Rep 2021; 11:260. [PMID: 33420098 PMCID: PMC7794404 DOI: 10.1038/s41598-020-79046-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 12/01/2020] [Indexed: 02/01/2023] Open
Abstract
Genetic diversity feeds the evolutionary process and allows populations to adapt to environmental changes. However, we still lack a thorough understanding of why hotspots of genetic diversity are so 'hot'. Here, we analysed the relative contribution of bioclimatic stability and genetic admixture between divergent lineages in shaping spatial patterns of genetic diversity in the common toad Bufo bufo along the Italian peninsula. We combined population genetic, phylogeographic and species distribution modelling (SDM) approaches to map ancestral areas, glacial refugia, and secondary contact zones. We consistently identified three phylogeographic lineages, distributed in northern, central and southern Italy. These lineages expanded from their ancestral areas and established secondary contact zones, before the last interglacial. SDM identified widespread glacial refugia in peninsular Italy, sometimes located under the present-day sea-level. Generalized linear models indicated genetic admixture as the only significant predictor of the levels of population genetic diversity. Our results show that glacial refugia contributed to preserving both levels and patterns of genetic diversity across glacial-interglacial cycles, but not to their formation, and highlight a general principle emerging in Mediterranean species: higher levels of genetic diversity mark populations with substantial contributions from multiple genetic lineages, irrespective of the location of glacial refugia.
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Affiliation(s)
- Andrea Chiocchio
- Department of Ecological and Biological Science, Tuscia University, Largo dell'Università s.n.c., 01100, Viterbo, Italy.
| | - Jan W Arntzen
- Naturalis Biodiversity Center, P.O. Box 9517, 2300 RA, Leiden, The Netherlands
| | - Iñigo Martínez-Solano
- Department of Biodiversity and Evolutionary Biology, Museo Nacional de Ciencias Naturales, CSIC, c/ José Gutiérrez Abascal 2, 28006, Madrid, Spain
| | - Wouter de Vries
- Asociation Ambor, Ctra. Constantina - Pedroso 1, 41450, Constantina, Spain
| | - Roberta Bisconti
- Department of Ecological and Biological Science, Tuscia University, Largo dell'Università s.n.c., 01100, Viterbo, Italy
| | - Alice Pezzarossa
- Department of Ecological and Biological Science, Tuscia University, Largo dell'Università s.n.c., 01100, Viterbo, Italy
| | - Luigi Maiorano
- Department of Biology and Biotechnology "Charles Darwin", Università di Roma La Sapienza, Viale dell'Università 32, 00185, Rome, Italy
| | - Daniele Canestrelli
- Department of Ecological and Biological Science, Tuscia University, Largo dell'Università s.n.c., 01100, Viterbo, Italy
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15
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Dufresnes C, Probonas NM, Strachinis I. A reassessment of the diversity of green toads (Bufotes) in the circum-Aegean region. Integr Zool 2020; 16:420-428. [PMID: 32978888 DOI: 10.1111/1749-4877.12494] [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] [Indexed: 01/26/2023]
Abstract
The dynamic biogeography of glacial refugia may cause complex patterns of genetic admixture between parapatric taxa, which in turn can mislead their systematics, diversity, and distributions. We investigated this issue for green toads (Bufotes) inhabiting the circum-Aegean region, a biodiversity hotspot of the Eastern Mediterranean. A previous phylogeographic study based on mitochondrial and microsatellite loci identified the hybrid zone between the European (viridis) and Anatolian (sitibundus) lineages of B. viridis all over the Balkan Peninsula, but subsequent range-wide genomic analyses (>1000 SNPs) located this transition in Turkey, a thousand kilometers eastwards. In order to clarify the diversity and taxonomy of the circum-Aegean populations, we reconciled these conflicting findings by integrating previous data with pure sitibundus individuals. Our results confirmed that the viridis/sitibundus hybrid zone extends in Western Anatolia, but that southeastern European populations feature cytonuclear discordances and a high and structured microsatellite diversity. This remarkable situation may stem from a massive geographic displacement of the hybrid zone during the last glacial fluctuations, an underappreciated yet seemingly common feature among the herpetofauna of the region. Our study thus contributes to the rising view that mitochondrial DNA can be a poor predictor of current phylogeographic structure, hence the need for genomic data, especially for narrowly distributed taxa. Finally, the analyses unambiguously support the distinction of a micro-endemic clade of green toads unique to some Cyclades islands, for which we provide a formal taxonomic description.
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Affiliation(s)
- Christophe Dufresnes
- LASER, College of Biology and the Environment, Nanjing Forestry University, Nanjing, People's Republic of China
| | | | - Ilias Strachinis
- Department of Genetics, Development and Molecular Biology, School of Biology, Faculty of Natural Sciences, Aristotle University of Thessaloniki, Thessaloniki, Greece
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16
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Dufresnes C, Litvinchuk SN, Rozenblut-Kościsty B, Rodrigues N, Perrin N, Crochet PA, Jeffries DL. Hybridization and introgression between toads with different sex chromosome systems. Evol Lett 2020; 4:444-456. [PMID: 33014420 PMCID: PMC7523563 DOI: 10.1002/evl3.191] [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: 04/16/2020] [Revised: 07/28/2020] [Accepted: 07/29/2020] [Indexed: 01/26/2023] Open
Abstract
The growing interest in the lability of sex determination in non‐model vertebrates such as amphibians and fishes has revealed high rates of sex chromosome turnovers among closely related species of the same clade. Can such lineages hybridize and admix with different sex‐determining systems, or could the changes have precipitated their speciation? We addressed these questions in incipient species of toads (Bufonidae), where we identified a heterogametic transition and characterized their hybrid zone with genome‐wide markers (RADseq). Adult and sibship data confirmed that the common toad B. bufo is female heterogametic (ZW), while its sister species the spined toad B. spinosus is male heterogametic (XY). Analysis of a fine scale transect across their parapatric ranges in southeastern France unveiled a narrow tension zone (∼10 km), with asymmetric mitochondrial and nuclear admixture over hundreds of kilometers southward and northward, respectively. The geographic extent of introgression is consistent with an expansion of B. spinosus across B. bufo’s former ranges in Mediterranean France, as also suggested by species distribution models. However, widespread cyto‐nuclear discordances (B. spinosus backrosses carrying B. bufo mtDNA) run against predictions from the dominance effects of Haldane's rule, perhaps because Y and W heterogametologs are not degenerated. Common and spined toads can thus successfully cross‐breed despite fundamental differences in their sex determination mechanisms, but remain partially separated by reproductive barriers. Whether and how the interactions of their XY and ZW genes contribute to these barriers shall provide novel insights on the debated role of labile sex chromosomes in speciation.
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Affiliation(s)
- Christophe Dufresnes
- LASER College of Biology and the Environment Nanjing Forestry University Nanjing People's Republic of China.,Department of Animal and Plant Sciences University of Sheffield Sheffield United Kingdom
| | - Spartak N Litvinchuk
- Institute of Cytology Russian Academy of Sciences Saint Petersburg Russia.,Dagestan State University Makhachkala Russia
| | - Beata Rozenblut-Kościsty
- Department of Evolutionary Biology and Conservation of Vertebrates Faculty of Biological Sciences University of Wrocław Wrocław Poland
| | - Nicolas Rodrigues
- Department of Ecology & Evolution University of Lausanne Lausanne Switzerland
| | - Nicolas Perrin
- Department of Ecology & Evolution University of Lausanne Lausanne Switzerland
| | - Pierre-André Crochet
- CEFE Univ. Montpellier, CNRS, EPHE, IRD Univ Paul Valéry Montpellier 3 Montpellier France
| | - Daniel L Jeffries
- Department of Ecology & Evolution University of Lausanne Lausanne Switzerland
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17
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McEntee JP, Burleigh JG, Singhal S. Dispersal Predicts Hybrid Zone Widths across Animal Diversity: Implications for Species Borders under Incomplete Reproductive Isolation. Am Nat 2020; 196:9-28. [PMID: 32552108 DOI: 10.1086/709109] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Hybrid zones occur as range boundaries for many animal taxa. One model for how hybrid zones form and stabilize is the tension zone model, a version of which predicts that hybrid zone widths are determined by a balance between random dispersal into hybrid zones and selection against hybrids. Here, we examine whether random dispersal and proxies for selection against hybrids (genetic distances between hybridizing pairs) can explain variation in hybrid zone widths across 131 hybridizing pairs of animals. We show that these factors alone can explain ∼40% of the variation in zone width among animal hybrid zones, with dispersal explaining far more of the variation than genetic distances. Patterns within clades were idiosyncratic. Genetic distances predicted hybrid zone widths particularly well for reptiles, while this relationship was opposite tension zone predictions in birds. Last, the data suggest that dispersal and molecular divergence set lower bounds on hybrid zone widths in animals, indicating that there are geographic restrictions on hybrid zone formation. Overall, our analyses reinforce the fundamental importance of dispersal in hybrid zone formation and more generally in the ecology of range boundaries.
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18
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Menon M, Landguth E, Leal‐Saenz A, Bagley JC, Schoettle AW, Wehenkel C, Flores‐Renteria L, Cushman SA, Waring KM, Eckert AJ. Tracing the footprints of a moving hybrid zone under a demographic history of speciation with gene flow. Evol Appl 2020; 13:195-209. [PMID: 31892952 PMCID: PMC6935588 DOI: 10.1111/eva.12795] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 02/20/2019] [Accepted: 03/19/2019] [Indexed: 02/07/2023] Open
Abstract
A lack of optimal gene combinations, as well as low levels of genetic diversity, is often associated with the formation of species range margins. Conservation efforts rely on predictive modelling using abiotic variables and assessments of genetic diversity to determine target species and populations for controlled breeding, germplasm conservation and assisted migration. Biotic factors such as interspecific competition and hybridization, however, are largely ignored, despite their prevalence across diverse taxa and their role as key evolutionary forces. Hybridization between species with well-developed barriers to reproductive isolation often results in the production of offspring with lower fitness. Generation of novel allelic combinations through hybridization, however, can also generate positive fitness consequences. Despite this possibility, hybridization-mediated introgression is often considered a threat to biodiversity as it can blur species boundaries. The contribution of hybridization towards increasing genetic diversity of populations at range margins has only recently gathered attention in conservation studies. We assessed the extent to which hybridization contributes towards range dynamics by tracking spatio-temporal changes in the central location of a hybrid zone between two recently diverged species of pines: Pinus strobiformis and P. flexilis. By comparing geographic cline centre estimates for global admixture coefficient with morphological traits associated with reproductive output, we demonstrate a northward shift in the hybrid zone. Using a combination of spatially explicit, individual-based simulations and linkage disequilibrium variance partitioning, we note a significant contribution of adaptive introgression towards this northward movement, despite the potential for differences in regional population size to aid hybrid zone movement. Overall, our study demonstrates that hybridization between recently diverged species can increase genetic diversity and generate novel allelic combinations. These novel combinations may allow range margin populations to track favourable climatic conditions or facilitate adaptive evolution to ongoing and future climate change.
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Affiliation(s)
- Mitra Menon
- Integrative Life SciencesVirginia Commonwealth UniversityRichmondVirginia
| | - Erin Landguth
- School of Public and Community Health SciencesUniversity of MontanaMissoulaMontana
| | - Alejandro Leal‐Saenz
- Programa Institucional de Doctorado en Ciencias Agropecuarias y ForestalesUniversidad Juárez del Estado de DurangoDurangoMexico
| | - Justin C. Bagley
- Department of BiologyVirginia Commonwealth UniversityRichmondVirginia
| | - Anna W. Schoettle
- Rocky Mountain Research StationUSDA Forest ServiceFort CollinsColorado
| | - Christian Wehenkel
- Instituto de Silvicultura e Industria de la MaderaUniversidad Juarez del Estado de DurangoDurangoMexico
| | | | | | | | - Andrew J. Eckert
- Department of BiologyVirginia Commonwealth UniversityRichmondVirginia
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19
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Arntzen JW. An amphibian species pushed out of Britain by a moving hybrid zone. Mol Ecol 2019; 28:5145-5154. [PMID: 31643124 PMCID: PMC6900066 DOI: 10.1111/mec.15285] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 10/17/2019] [Accepted: 10/21/2019] [Indexed: 02/06/2023]
Abstract
Classical theory states that hybrid zones will be stable in troughs of low population density where dispersal is hampered. Yet, evidence for moving hybrid zones is mounting. One possible reason that moving zones have been underappreciated is that they may drive themselves into oblivion and with just the superseding species remaining, morphological and genetic signals of past species replacement may be difficult to appreciate. Using genetic data (32 diagnostic single nucleotide polymorphisms) from a clinal hybrid zone of the common toad (Bufo bufo) and the spined toad (Bufo spinosus) in France for comparison, alleles of the latter species were documented in common toads in the south of Great Britain, at frequencies in excess of 10%. Because long distance dispersal across the Channel is unlikely, the conclusion reached was that the continental toad hybrid zone which previously extended into Britain, moved southwards and extirpated B. spinosus. Species distribution models for the mid-Holocene and the present support that climate has locally changed in favour of B. bufo. The system bears resemblance with the demise of Homo neanderthalensis and the rise of Homo sapiens and provides an example that some paleoanthropologists demanded in support of a hominin "leaky replacement" scenario. The toad example is informative just because surviving pure B. spinosus and an extant slowly moving interspecific hybrid zone are available for comparison.
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20
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van Riemsdijk I, Butlin RK, Wielstra B, Arntzen JW. Testing an hypothesis of hybrid zone movement for toads in France. Mol Ecol 2019; 28:1070-1083. [PMID: 30609055 DOI: 10.1111/mec.15005] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 12/08/2018] [Accepted: 12/19/2018] [Indexed: 02/06/2023]
Abstract
Hybrid zone movement may result in substantial unidirectional introgression of selectively neutral material from the local to the advancing species, leaving a genetic footprint. This genetic footprint is represented by a trail of asymmetric tails and displaced cline centres in the wake of the moving hybrid zone. A peak of admixture linkage disequilibrium is predicted to exist ahead of the centre of the moving hybrid zone. We test these predictions of the movement hypothesis in a hybrid zone between common (Bufo bufo) and spined toads (B. spinosus), using 31 nuclear and one mtDNA SNPs along a transect in the northwest of France. Average effective selection in Bufo hybrids is low and clines vary in shape and centre. A weak pattern of asymmetric introgression is inferred from cline discordance of seven nuclear markers. The dominant direction of gene flow is from B. spinosus to B. bufo and is in support of southward movement of the hybrid zone. Conversely, a peak of admixture linkage disequilibrium north of the hybrid zone suggests northward movement. These contrasting results can be explained by reproductive isolation of the B. spinosus and B. bufo gene pools at the southern (B. spinosus) side of the hybrid zone. The joint occurrence of asymmetric introgression and admixture linkage disequilibrium can also be explained by the combination of low dispersal and random genetic drift due to low effective population sizes.
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Affiliation(s)
- Isolde van Riemsdijk
- Taxonomy and Systematics, Naturalis Biodiversity Center, Leiden, The Netherlands.,Institute of Biology Leiden, Leiden University, Leiden, The Netherlands
| | - Roger K Butlin
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK.,Department of Marine Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Ben Wielstra
- Taxonomy and Systematics, Naturalis Biodiversity Center, Leiden, The Netherlands.,Institute of Biology Leiden, Leiden University, Leiden, The Netherlands.,Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK.,Department of Ecology and Evolutionary Biology, University of California, Los Angeles, California
| | - Jan W Arntzen
- Taxonomy and Systematics, Naturalis Biodiversity Center, Leiden, The Netherlands
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21
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Sequeira F, Bessa-Silva A, Tarroso P, Sousa-Neves T, Vallinoto M, Gonçalves H, Martínez-Solano I. Discordant patterns of introgression across a narrow hybrid zone between two cryptic lineages of an Iberian endemic newt. J Evol Biol 2019; 33:202-216. [PMID: 31677317 DOI: 10.1111/jeb.13562] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 10/15/2019] [Accepted: 10/25/2019] [Indexed: 11/30/2022]
Abstract
The study of natural hybrid zones can illuminate aspects of lineage divergence and speciation in morphologically cryptic taxa. We studied a hybrid zone between two highly divergent but morphologically similar lineages (south-western and south-eastern) of the Iberian endemic Bosca's newt (Lissotriton boscai) in SW Iberia with a multilocus dataset (microsatellites, nuclear and mitochondrial genes). STRUCTURE and NEWHYBRIDS analyses retrieved few admixed individuals, which classified as backcrosses involving parental individuals of the south-western lineage. Our results show asymmetric introgression of mtDNA beyond the contact from this lineage into the south-eastern lineage. Analysis of nongeographic introgression patterns revealed asymmetries in the direction of introgression, but except for mtDNA, we did not find evidence for nonconcordant introgression patterns across nuclear loci. Analysis of a 150-km transect across the hybrid zone showed broadly coincident cline widths (ca. 3.2-27.9 km), and concordant cline centres across all markers, except for mtDNA that is displaced ca. 60 km northward. Results from ecological niche modelling show that the hybrid zone is in a climatically homogenous area with suitable habitat for the species, suggesting that contact between the two lineages is unlikely to occur further south as their distributions are currently separated by an extensive area of unfavourable habitat. Taken together, our findings suggest the genetic structure of this hybrid zone results from the interplay of historical (biogeographic) and population-level processes. The narrowness and coincidence of genetic clines can be explained by weak selection against hybrids and reflect a degree of reproductive isolation that is consistent with cryptic speciation.
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Affiliation(s)
- Fernando Sequeira
- Laboratorio Associado, CIBIO-InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO, Universidade do Porto, Vairão, Portugal
| | - Adam Bessa-Silva
- Laboratório de Evolução (LEVO), Instituto de Estudos Costeiros (IECOS), Universidade Federal do Pará, Pará, Brasil
| | - Pedro Tarroso
- Laboratorio Associado, CIBIO-InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO, Universidade do Porto, Vairão, Portugal
| | - Tiago Sousa-Neves
- Laboratorio Associado, CIBIO-InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO, Universidade do Porto, Vairão, Portugal.,Museu Paraense Emílio Goeldi, Coordenação de Zoologia, Pará, Brasil
| | - Marcelo Vallinoto
- Laboratorio Associado, CIBIO-InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO, Universidade do Porto, Vairão, Portugal.,Laboratório de Evolução (LEVO), Instituto de Estudos Costeiros (IECOS), Universidade Federal do Pará, Pará, Brasil
| | - Helena Gonçalves
- Laboratorio Associado, CIBIO-InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO, Universidade do Porto, Vairão, Portugal.,Museu de História Natural e da Ciência, Universidade do Porto, Porto, Portugal
| | - Iñigo Martínez-Solano
- Department of Biodiversity and Evolutionary Biology, Museo Nacional de Ciencias Naturales, CSIC (MNCN-CSIC), Madrid, Spain
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22
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Dufresnes C, Strachinis I, Suriadna N, Mykytynets G, Cogălniceanu D, Székely P, Vukov T, Arntzen JW, Wielstra B, Lymberakis P, Geffen E, Gafny S, Kumlutaş Y, Ilgaz Ç, Candan K, Mizsei E, Szabolcs M, Kolenda K, Smirnov N, Géniez P, Lukanov S, Crochet PA, Dubey S, Perrin N, Litvinchuk SN, Denoël M. Phylogeography of a cryptic speciation continuum in Eurasian spadefoot toads (Pelobates). Mol Ecol 2019; 28:3257-3270. [PMID: 31254307 DOI: 10.1111/mec.15133] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Revised: 03/30/2019] [Accepted: 05/17/2019] [Indexed: 12/15/2022]
Abstract
Cryptic phylogeographic diversifications provide unique models to examine the role of phylogenetic divergence on the evolution of reproductive isolation, without extrinsic factors such as ecological and behavioural differentiation. Yet, to date very few comparative studies have been attempted within such radiations. Here, we characterize a new speciation continuum in a group of widespread Eurasian amphibians, the Pelobates spadefoot toads, by conducting multilocus (restriction site associated DNA sequencing and mitochondrial DNA) phylogenetic, phylogeographic and hybrid zone analyses. Within the P. syriacus complex, we discovered species-level cryptic divergences (>5 million years ago [My]) between populations distributed in the Near-East (hereafter P. syriacus sensu stricto [s.s.]) and southeastern Europe (hereafter P. balcanicus), each featuring deep intraspecific lineages. Altogether, we could scale hybridizability to divergence time along six different stages, spanning from sympatry without gene flow (P. fuscus and P. balcanicus, >10 My), parapatry with highly restricted hybridization (P. balcanicus and P. syriacus s.s., >5 My), narrow hybrid zones (~15 km) consistent with partial reproductive isolation (P. fuscus and P. vespertinus, ~3 My), to extensive admixture between Pleistocene and refugial lineages (≤2 My). This full spectrum empirically supports a gradual build up of reproductive barriers through time, reversible up until a threshold that we estimate at ~3 My. Hence, cryptic phylogeographic lineages may fade away or become reproductively isolated species simply depending on the time they persist in allopatry, and without definite ecomorphological divergence.
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Affiliation(s)
- Christophe Dufresnes
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK.,Hintermann & Weber SA, Montreux, Switzerland.,Laboratory for Conservation Biology, University of Lausanne, Lausanne, Switzerland
| | - Ilias Strachinis
- School of Biology, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Nataliia Suriadna
- Melitopol Insitute of Ecology and Social Technologies of University "Ukraine", Melitopol, Zaporizhia, Ukraine
| | | | - Dan Cogălniceanu
- Faculty of Natural Sciences and Agricultural Sciences, University Ovidius Constanţa, Constanţa, Romania
| | - Paul Székely
- Departamento de Ciencias Biológicas, EcoSs Lab, Universidad Técnica Particular de Loja, Loja, Ecuador
| | - Tanja Vukov
- Department of Evolutionary Biology, Institute for Biological Research "Siniša Stanković", National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - Jan W Arntzen
- Naturalis Biodiversity Center, Leiden, The Netherlands
| | - Ben Wielstra
- Naturalis Biodiversity Center, Leiden, The Netherlands.,Institute of Biology Leiden, Leiden University, Leiden, The Netherlands
| | - Petros Lymberakis
- Natural History Museum of Crete, University of Crete, Irakleio, Crete, Greece
| | - Eli Geffen
- School of Zoology, Tel Aviv University, Tel Aviv, Israel
| | - Sarig Gafny
- School of Marine Sciences, Ruppin Academic Center, Michmoret, Israel
| | - Yusuf Kumlutaş
- Department of Biology, Faculty of Science, Dokuz Eylül University, Buca, İzmir, Turkey.,Research and Application Center for Fauna and Flora, Dokuz Eylül University, Buca, İzmir, Turkey
| | - Çetin Ilgaz
- Department of Biology, Faculty of Science, Dokuz Eylül University, Buca, İzmir, Turkey.,Research and Application Center for Fauna and Flora, Dokuz Eylül University, Buca, İzmir, Turkey
| | - Kamil Candan
- Department of Biology, Faculty of Science, Dokuz Eylül University, Buca, İzmir, Turkey.,Research and Application Center for Fauna and Flora, Dokuz Eylül University, Buca, İzmir, Turkey
| | - Edvárd Mizsei
- Department of Tisza River Research, Danube Research Institute, Centre for Ecological Research, Hungarian Academy of Sciences, Debrecen, Hungary
| | - Márton Szabolcs
- Department of Tisza River Research, Danube Research Institute, Centre for Ecological Research, Hungarian Academy of Sciences, Debrecen, Hungary
| | - Krzysztof Kolenda
- Department of Evolutionary Biology and Conservation of Vertebrates, Institute of Environmental Biology, University of Wrocław, Wrocław, Poland
| | - Nazar Smirnov
- Department of Nature, Chernivtsi Regional Museum, Chernivtsi, Ukraine
| | - Philippe Géniez
- CEFE, EPHE-PSL, CNRS, University of Montpellier, University Paul Valéry Montpellier 3, IRD, Montpellier, France
| | - Simeon Lukanov
- Institute of Biodiversity and Ecosystem Research, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Pierre-André Crochet
- CEFE, CNRS, University of Montpellier, University Paul Valéry Montpellier 3, EPHE, IRD, Montpellier, France
| | - Sylvain Dubey
- Hintermann & Weber SA, Montreux, Switzerland.,Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland.,Agrosustain SA, Nyon, Switzerland
| | - Nicolas Perrin
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
| | - Spartak N Litvinchuk
- Institute of Cytology, Russian Academy of Sciences, St. Petersburg, Russia.,Department of Zoology and Physiology, Dagestan State University, Makhachkala, Russia
| | - Mathieu Denoël
- Laboratory of Fish and Amphibian Ethology, Behavioural Biology Group, Freshwater and OCeanic science Unit of reSearch (FOCUS), University of Liège, Liège, Belgium
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Pöschel J, Heltai B, Graciá E, Quintana MF, Velo-Antón G, Arribas O, Valdeón A, Wink M, Fritz U, Vamberger M. Complex hybridization patterns in European pond turtles (Emys orbicularis) in the Pyrenean Region. Sci Rep 2018; 8:15925. [PMID: 30374044 PMCID: PMC6206128 DOI: 10.1038/s41598-018-34178-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 10/06/2018] [Indexed: 11/29/2022] Open
Abstract
Hybrid zones are natural laboratories allowing insights in genetic processes like lineage diversification, speciation and introgression. Using large sampling, 15 microsatellite loci and a mitochondrial marker, we examined the Pyrenean contact zone of three pond turtle taxa (Emys orbicularis orbicularis, E. o. galloitalica, E. o. occidentalis). The Pyrenees are a biogeographically important region separating many lineages endemic to the Iberian Peninsula from their Western European counterparts. We discovered limited admixture, reflecting a complex biogeographic scenario. Simulations using Approximate Bayesian Computing supported that E. o. orbicularis invaded the Iberian Peninsula in the Holocene, circumventing the Pyrenees along the Mediterranean coast, and hybridized in the northern peninsula with the local coastal subspecies galloitalica, and to a lesser extent, with occidentalis. While E. o. occidentalis, and in particular E. o. orbicularis, expanded their ranges considerably during Holocene warming, E. o. galloitalica remained largely confined to its former Iberian refuge. Admixture among the three taxa is surprisingly low, and a future taxonomic investigation that includes the unstudied subspecies of E. orbicularis from North Africa, Eastern Europe and Asia has to determine whether their current status properly reflects their evolutionary divergence or whether certain taxa should be regarded as full species.
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Affiliation(s)
- Julia Pöschel
- Museum of Zoology (Museum für Tierkunde), Senckenberg Dresden, A. B. Meyer Building, 01109, Dresden, Germany
| | - Botond Heltai
- Agricultural Biotechnology Institute - National Agricultural Research and Innovation Center, Szent-Györgyi Albert u. 4, 2100, Gödöllő, Hungary
| | - Eva Graciá
- Ecology Area, Department of Applied Biology, Miguel Hernández University, Av. de la Universidad, Torreblanca, 03202, Elche, Spain
| | - Marc Franch Quintana
- CICGE - Centro de Investigação em Ciências Geo-Espaciais, Universidade de Porto, Observatório Astronómico Prof. Manuel de Barros Alameda do Monte da Virgem, 4430-146, Vila Nova de Gaia, Portugal
| | - Guillermo Velo-Antón
- CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos da Universidade do Porto, Instituto de Ciências Agrárias de Vairão, R. Padre Armando Quintas 7, 4485-661, Vairão, Portugal
| | | | - Aitor Valdeón
- Department of Geography and Regional Planning, University of Zaragoza, Pedro Cerbuna 12, 50009, Zaragoza, Spain.,Aranzadi Society of Sciences, Zorroagagaina, 11, 20014, Donostia-San Sebastian, Spain
| | - Michael Wink
- Heidelberg University, Institute of Pharmacy and Molecular Biotechnology, Im Neuenheimer Feld 364, 69120, Heidelberg, Germany
| | - Uwe Fritz
- Museum of Zoology (Museum für Tierkunde), Senckenberg Dresden, A. B. Meyer Building, 01109, Dresden, Germany
| | - Melita Vamberger
- Museum of Zoology (Museum für Tierkunde), Senckenberg Dresden, A. B. Meyer Building, 01109, Dresden, Germany.
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Dufresnes C, Lymberakis P, Kornilios P, Savary R, Perrin N, Stöck M. Phylogeography of Aegean green toads (Bufo viridis subgroup): continental hybrid swarm vs. insular diversification with discovery of a new island endemic. BMC Evol Biol 2018; 18:67. [PMID: 29720079 PMCID: PMC5930823 DOI: 10.1186/s12862-018-1179-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 04/16/2018] [Indexed: 11/18/2022] Open
Abstract
Background Debated aspects in speciation research concern the amount of gene flow between incipient species under secondary contact and the modes by which post-zygotic isolation accumulates. Secondary contact zones of allopatric lineages, involving varying levels of divergence, provide natural settings for comparative studies, for which the Aegean (Eastern Mediterranean) geography offers unique scenarios. In Palearctic green toads (Bufo viridis subgroup or Bufotes), Plio-Pleistocene (~ 2.6 Mya) diverged species show a sharp transition without contemporary gene flow, while younger lineages, diverged in the Lower-Pleistocene (~ 1.9 Mya), admix over tens of kilometers. Here, we conducted a fine-scale multilocus phylogeographic analysis of continental and insular green toads from the Aegean, where a third pair of taxa, involving Mid-Pleistocene diverged (~ 1.5 Mya) mitochondrial lineages, earlier tentatively named viridis and variabilis, (co-)occurs. Results We discovered a new lineage, endemic to Naxos (Central Cyclades), while coastal islands and Crete feature weak genetic differentiation from the continent. In continental Greece, both lineages, viridis and variabilis, form a hybrid swarm, involving massive mitochondrial and nuclear admixture over hundreds of kilometers, without obvious selection against hybrids. Conclusions The genetic signatures of insular Aegean toads appear governed by bathymetry and Quaternary sea level changes, resulting in long-term isolation (Central Cyclades: Naxos) and recent land-bridges (coastal islands). Conversely, Crete has been isolated since the end of the Messinian salinity crisis (5.3 My) and Cretan populations thus likely result from human-mediated colonization, at least since Antiquity, from Peloponnese and Anatolia. Comparisons of green toad hybrid zones support the idea that post-zygotic hybrid incompatibilities accumulate gradually over the genome. In this radiation, only one million years of divergence separate a scenario of complete reproductive isolation, from a secondary contact resulting in near panmixia. Electronic supplementary material The online version of this article (10.1186/s12862-018-1179-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Christophe Dufresnes
- Department of Ecology & Evolution, University of Lausanne, Biophore Building, 1015, Lausanne, Switzerland.,Department of Animal and Plant Sciences, University of Sheffield, Alfred Denny Building, Western Bank, Sheffield, S10 2TN, UK
| | - Petros Lymberakis
- Natural History Museum of Crete, University of Crete, Knosos Av, P.O. Box 2208, 71409, Irakleio, Crete, Greece
| | - Panagiotis Kornilios
- Section of Animal Biology, Department of Biology, School of Natural Sciences, University of Patras, GR-26500, Patras, Greece.,Department of Biology, University of Washington, Box 351800, Seattle, WA, 98195-1800, USA
| | - Romain Savary
- Department of Ecology & Evolution, University of Lausanne, Biophore Building, 1015, Lausanne, Switzerland
| | - Nicolas Perrin
- Department of Ecology & Evolution, University of Lausanne, Biophore Building, 1015, Lausanne, Switzerland
| | - Matthias Stöck
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Müggelseedamm 301, D-12587, Berlin, Germany.
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Souissi A, Bonhomme F, Manchado M, Bahri-Sfar L, Gagnaire PA. Genomic and geographic footprints of differential introgression between two divergent fish species (Solea spp.). Heredity (Edinb) 2018; 121:579-593. [PMID: 29713088 DOI: 10.1038/s41437-018-0079-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 02/12/2018] [Accepted: 03/10/2018] [Indexed: 11/09/2022] Open
Abstract
Investigating gene flow between closely related species and its variation across the genome is important to understand how reproductive barriers shape genome divergence before speciation is complete. An efficient way to characterize differential gene flow is to study how the genetic interactions that take place in hybrid zones selectively filter gene exchange between species, leading to heterogeneous genome divergence. In the present study, genome-wide divergence and introgression patterns were investigated between two sole species, Solea senegalensis and Solea aegyptiaca, using restriction-associated DNA sequencing (RAD-Seq) to analyze samples taken from a transect spanning the hybrid zone. An integrative approach combining geographic and genomic clines methods with an analysis of individual locus introgression accounting for the demographic history of divergence was conducted. Our results showed that the two sole species have come into secondary contact postglacially, after experiencing a prolonged period (ca. 1.1 to 1.8 Myrs) of allopatric separation. Secondary contact resulted in the formation of a tension zone characterized by strong reproductive isolation, which only allowed introgression in a limited fraction of the genome. We found multiple evidence for a preferential direction of introgression in the S. aegyptiaca genetic background, indicating a possible recent or ongoing movement of the hybrid zone. Deviant introgression signals found in the opposite direction suggested that S. senegalensis could have possibly undergone adaptive introgression that has not yet spread throughout the entire species range. Our study thus illustrates the varied outcomes of genetic interactions between divergent gene pools that recently met after a long history of divergence.
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Affiliation(s)
- Ahmed Souissi
- Université de Montpellier, Place Eugène Bataillon, 34095, Montpellier, France. .,CNRS-Institut des Sciences de l'Evolution, UMR5554 UM-CNRS-IRD-EPHE, Station Méditerranéenne de l'Environnement Littoral, 34200, Sète, France. .,Faculté des Sciences de Tunis UR11ES08 Biologie intégrative et écologie évolutive et fonctionnelle des milieux aquatiques, Université de Tunis El Manar, 2092, Tunis, Tunisia.
| | - François Bonhomme
- Université de Montpellier, Place Eugène Bataillon, 34095, Montpellier, France.,CNRS-Institut des Sciences de l'Evolution, UMR5554 UM-CNRS-IRD-EPHE, Station Méditerranéenne de l'Environnement Littoral, 34200, Sète, France
| | - Manuel Manchado
- IFAPA Centro El Toruño, Junta de Andalucía, Camino Tiro Pichón s/n, 11500, El Puerto de Santa María, Cádiz, Spain
| | - Lilia Bahri-Sfar
- Faculté des Sciences de Tunis UR11ES08 Biologie intégrative et écologie évolutive et fonctionnelle des milieux aquatiques, Université de Tunis El Manar, 2092, Tunis, Tunisia
| | - Pierre-Alexandre Gagnaire
- Université de Montpellier, Place Eugène Bataillon, 34095, Montpellier, France.,CNRS-Institut des Sciences de l'Evolution, UMR5554 UM-CNRS-IRD-EPHE, Station Méditerranéenne de l'Environnement Littoral, 34200, Sète, France
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26
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Arntzen JW, McAtear J, Butôt R, Martínez-Solano I. A common toad hybrid zone that runs from the Atlantic to the Mediterranean. AMPHIBIA-REPTILIA 2018. [DOI: 10.1163/15685381-00003145] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We document the distribution of the common toadBufo bufoand the spined toadB. spinosusat their contact zone across France with data from a mitochondrial DNA RFLP assay, complementing similar work including nuclear markers in the northwest and southeast of France and in Italy. We also reconstruct geographical clines across the species’ contact zone in central France.Bufo bufois found in the north-eastern half of France.Bufo spinosusis found in the south-western complement. The contact zone they form runs from the Atlantic coast near Caen, France, to the Mediterranean coast near Savona, Italy, and has a length of over 900 km. In central FranceB. bufoandB. spinosusengage in a hybrid zone with a unimodal genetic signature. Hybrid zone width is ca. 10 km at mitochondrial DNA and averages at 61 km for four nuclear loci. The hybrid zone is distinctly asymmetric with a signature ofB. spinosusinB. bufoand not the other way round. We attribute this observation toB. bufomoving southwards at the expense ofB. spinosus, with introgression in the direction of the advancing species. We noted substantial geographic variation in characters for species identification. Morphological species identification performs well in France, but breaks down in Italy. Mitochondrial DNA is inconclusive in south-eastern France and Italy. The nuclear genetic markers perform consistently well but have not yet been applied to the zone in full. Possible, but surely heterogeneous ecological correlates for the position of the hybrid zone are mountains and rivers.
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Affiliation(s)
- Jan W. Arntzen
- Naturalis Biodiversity Center, P.O. Box 9517, 2300 RA Leiden, The Netherlands
| | - Jacob McAtear
- Naturalis Biodiversity Center, P.O. Box 9517, 2300 RA Leiden, The Netherlands
| | - Roland Butôt
- Naturalis Biodiversity Center, P.O. Box 9517, 2300 RA Leiden, The Netherlands
| | - Iñigo Martínez-Solano
- Naturalis Biodiversity Center, P.O. Box 9517, 2300 RA Leiden, The Netherlands
- Evolution and Development Group, Department of Wetland Ecology, Doñana Biological Station, CSIC, c/ Americo Vespucio s/n, 41092 Seville, Spain
- Present address: Department of Biodiversity and Evolutionary Biology, Museo Nacional de Ciencias Naturales, CSIC, c/ José Gutiérrez Abascal 2, 28006 Madrid, Spain
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