1
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Martins ARP, Warren NB, McMillan WO, Barrett RDH. Spatiotemporal dynamics in butterfly hybrid zones. INSECT SCIENCE 2024; 31:328-353. [PMID: 37596954 DOI: 10.1111/1744-7917.13262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 07/13/2023] [Accepted: 07/21/2023] [Indexed: 08/21/2023]
Abstract
Evaluating whether hybrid zones are stable or mobile can provide novel insights for evolution and conservation biology. Butterflies exhibit high sensitivity to environmental changes and represent an important model system for the study of hybrid zone origins and maintenance. Here, we review the literature exploring butterfly hybrid zones, with a special focus on their spatiotemporal dynamics and the potential mechanisms that could lead to their movement or stability. We then compare different lines of evidence used to investigate hybrid zone dynamics and discuss the strengths and weaknesses of each approach. Our goal with this review is to reveal general conditions associated with the stability or mobility of butterfly hybrid zones by synthesizing evidence obtained using different types of data sampled across multiple regions and spatial scales. Finally, we discuss spatiotemporal dynamics in the context of a speciation/divergence continuum, the relevance of hybrid zones for conservation biology, and recommend key topics for future investigation.
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Affiliation(s)
- Ananda R Pereira Martins
- Redpath Museum, McGill University, 859 Sherbrooke Street West, Montreal, Quebec, Canada
- Smithsonian Tropical Research Institute, Gamboa, Panama City, Panama
| | - Natalie B Warren
- Redpath Museum, McGill University, 859 Sherbrooke Street West, Montreal, Quebec, Canada
| | - W Owen McMillan
- Smithsonian Tropical Research Institute, Gamboa, Panama City, Panama
| | - Rowan D H Barrett
- Redpath Museum, McGill University, 859 Sherbrooke Street West, Montreal, Quebec, Canada
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2
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Kalaentzis K, Arntzen JW, Avcı A, van den Berg V, Beukema W, France J, Olgun K, van Riemsdijk I, Üzüm N, de Visser MC, Wielstra B. Hybrid zone analysis confirms cryptic species of banded newt and does not support competitive displacement since secondary contact. Ecol Evol 2023; 13:e10442. [PMID: 37664506 PMCID: PMC10468612 DOI: 10.1002/ece3.10442] [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: 06/12/2023] [Revised: 08/02/2023] [Accepted: 08/08/2023] [Indexed: 09/05/2023] Open
Abstract
When two putatively cryptic species meet in nature, hybrid zone analysis can be used to estimate the extent of gene flow between them. Two recently recognized cryptic species of banded newt (genus Ommatotriton) are suspected to meet in parapatry in Anatolia, but a formal hybrid zone analysis has never been conducted. We sample populations throughout the range, with a focus on the supposed contact zone, and genotype them for 31 nuclear DNA SNP markers and mtDNA. We determine the degree of genetic admixture, introgression, and niche overlap. We reveal an extremely narrow hybrid zone, suggesting strong selection against hybrids, in line with species status. The hybrid zone does not appear to be positioned at an ecological barrier, and there is significant niche overlap. Therefore, the hybrid zone is best classified as a tension zone, maintained by intrinsic selection against hybrids. While the two banded newt species can evidently backcross, we see negligible introgression and the pattern is symmetric, which we interpret as supporting the fact that the hybrid zone has been practically stationary since its origin (while extensive hybrid zone movement has been suggested in other newt genera in the region). Our study illustrates the use of hybrid zone analysis to test cryptic species status.
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Affiliation(s)
- Konstantinos Kalaentzis
- Institute of Biology Leiden, Leiden UniversityLeidenThe Netherlands
- Naturalis Biodiversity CenterLeidenThe Netherlands
- Hydrobiological Station of Rhodes, Hellenic Centre for Marine ResearchRhodesGreece
| | - Jan W. Arntzen
- Institute of Biology Leiden, Leiden UniversityLeidenThe Netherlands
- Naturalis Biodiversity CenterLeidenThe Netherlands
| | - Aziz Avcı
- Department of BiologyAydın Adnan Menderes UniversityAydınTurkey
| | - Victor van den Berg
- Institute of Biology Leiden, Leiden UniversityLeidenThe Netherlands
- Naturalis Biodiversity CenterLeidenThe Netherlands
| | - Wouter Beukema
- Reptile, Amphibian and Fish Conservation Netherlands (RAVON)NijmegenThe Netherlands
| | - James France
- Institute of Biology Leiden, Leiden UniversityLeidenThe Netherlands
- Naturalis Biodiversity CenterLeidenThe Netherlands
| | - Kurtuluş Olgun
- Department of BiologyAydın Adnan Menderes UniversityAydınTurkey
| | - Isolde van Riemsdijk
- Institute of Biology Leiden, Leiden UniversityLeidenThe Netherlands
- Naturalis Biodiversity CenterLeidenThe Netherlands
- Plant Evolutionary EcologyInstitute of Evolution & Ecology, University of TübingenTübingenGermany
| | - Nazan Üzüm
- Department of BiologyAydın Adnan Menderes UniversityAydınTurkey
| | - Manon C. de Visser
- Institute of Biology Leiden, Leiden UniversityLeidenThe Netherlands
- Naturalis Biodiversity CenterLeidenThe Netherlands
| | - Ben Wielstra
- Institute of Biology Leiden, Leiden UniversityLeidenThe Netherlands
- Naturalis Biodiversity CenterLeidenThe Netherlands
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3
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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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4
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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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5
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Aguillon SM, Rohwer VG. Revisiting a classic hybrid zone: Movement of the northern flicker hybrid zone in contemporary times. Evolution 2022; 76:1082-1090. [PMID: 35318662 DOI: 10.1111/evo.14474] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 02/10/2022] [Accepted: 02/15/2022] [Indexed: 01/22/2023]
Abstract
Natural hybrid zones have provided important insights into the evolutionary process, and their geographic dynamics over time can help to disentangle the underlying biological processes that maintain them. Here, we leverage replicated sampling of an identical transect across the hybrid zone between yellow-shafted and red-shafted flickers in the Great Plains to assess its stability over ∼60 years (1955-1957 to 2016-2018). We identify a ∼73-km westward shift in the hybrid zone center toward the range of the red-shafted flicker, but find no associated changes in width over our sampling period. In fact, the hybrid zone remains remarkably narrow, suggesting some kind of selective pressure maintains the zone. By comparing to previous work in the same geographic region, it appears likely that the movement in the hybrid zone has occurred in the years since the early 1980s. This recent movement may be related to changes in climate or land management practices that have allowed westward movement of yellow-shafted flickers into the Great Plains.
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Affiliation(s)
- Stepfanie M Aguillon
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, New York, 14853.,Fuller Evolutionary Biology Program, Cornell Lab of Ornithology, Ithaca, New York, 14850.,Current Address: Department of Biology, Stanford University, Stanford, California, 94305
| | - Vanya G Rohwer
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, New York, 14853.,Cornell University Museum of Vertebrates, Ithaca, New York, 14850
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6
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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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7
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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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8
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Cruzan MB, Thompson PG, Diaz NA, Hendrickson EC, Gerloff KR, Kline KA, Machiorlete HM, Persinger JM. Weak coupling among barrier loci and waves of neutral and adaptive introgression across an expanding hybrid zone. Evolution 2021; 75:3098-3114. [PMID: 34668193 PMCID: PMC9298192 DOI: 10.1111/evo.14381] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 09/14/2021] [Accepted: 09/19/2021] [Indexed: 01/02/2023]
Abstract
Hybridization can serve as an evolutionary stimulus, but we have little understanding of introgression at early stages of hybrid zone formation. We analyze reproductive isolation and introgression between a range‐limited and a widespread species. Reproductive barriers are estimated based on differences in flowering time, ecogeographic distributions, and seed set from crosses. We find an asymmetrical mating barrier due to cytonuclear incompatibility that is consistent with observed clusters of coincident and concordant tension zone clines (barrier loci) for mtDNA haplotypes and nuclear SNPs. These groups of concordant clines are spread across the hybrid zone, resulting in weak coupling among barrier loci and extensive introgression. Neutral clines had nearly equal introgression into both species’ ranges, whereas putative cases of adaptive introgression had exceptionally wide clines with centers shifted toward one species. Analyses of cline shape indicate that secondary contact was initiated within the last 800 generations with the per‐generation dispersal between 200 and 400 m, and provide some of the first estimates of the strength of selection required to account for observed levels of adaptive introgression. The weak species boundary between these species appears to be in early stages of dissolution, and ultimately will precipitate genetic swamping of the range‐limited species.
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Affiliation(s)
- Mitchell B Cruzan
- Department of Biology, Portland State University, Portland, Oregon, 97201
| | - Pamela G Thompson
- Department of Biology, Portland State University, Portland, Oregon, 97201
| | - Nicolas A Diaz
- Department of Biology, Portland State University, Portland, Oregon, 97201
| | | | - Katie R Gerloff
- Department of Biology, Portland State University, Portland, Oregon, 97201
| | - Katie A Kline
- Department of Biology, Portland State University, Portland, Oregon, 97201
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9
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Tominaga A, Matsui M, Matsui M. Structure and movement of the hybrid zone between two divergent lineages of the Japanese newt
Cynops pyrrhogaster
(Amphibia: Urodela) in central Japan. J ZOOL SYST EVOL RES 2021. [DOI: 10.1111/jzs.12467] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
| | - Masafumi Matsui
- Graduate School of Human and Environmental Studies Kyoto University Kyoto Japan
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10
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López‐Delgado J, van Riemsdijk I, Arntzen JW. Tracing species replacement in Iberian marbled newts. Ecol Evol 2021; 11:402-414. [PMID: 33437438 PMCID: PMC7790658 DOI: 10.1002/ece3.7060] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Revised: 10/12/2020] [Accepted: 10/19/2020] [Indexed: 11/25/2022] Open
Abstract
Secondary contact between closely related species can lead to the formation of hybrid zones, allowing for interspecific gene flow. Hybrid zone movement can take place if one of the species possesses a competitive advantage over the other, ultimately resulting in species replacement. Such hybrid zone displacement is predicted to leave a genomic footprint across the landscape in the form of asymmetric gene flow (or introgression) of selectively neutral alleles from the displaced to the advancing species. Hybrid zone movement has been suggested for marbled newts in the Iberian Peninsula, supported by asymmetric gene flow and a distribution relict (i.e., an enclave) of Triturus marmoratus in the range of T. pygmaeus. We developed a panel of nuclear and mitochondrial SNP markers to test for the presence of a T. marmoratus genomic footprint in the Lisbon peninsula, south of the enclave. We found no additional populations of T. marmoratus. Analysis with the software Structure showed no genetic traces of T. marmoratus in T. pygmaeus. A principal component analysis showed some variation within the local T. pygmaeus, but it is unclear if this represents introgression from T. marmoratus. The results may be explained by (a) species replacement without introgressive hybridization and (b) displacement with hybridization followed by the near-complete erosion of the footprint by purifying selection. We predict that testing for a genomic footprint north of the reported enclave would confirm that species replacement in these marbled newts occurred with hybridization.
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Affiliation(s)
- Julia López‐Delgado
- Naturalis Biodiversity CenterLeidenThe Netherlands
- Institute for BiologyLeiden UniversityLeidenThe Netherlands
- Present address:
University of LeedsLeedsUnited Kingdom
| | - Isolde van Riemsdijk
- Naturalis Biodiversity CenterLeidenThe Netherlands
- Present address:
Institute for Evolution and Ecology, Tübingen UniversityLeedsGermany
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11
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Salces-Castellano A, Stankowski S, Arribas P, Patiño J, Karger DN, Butlin R, Emerson BC. Long-term cloud forest response to climate warming revealed by insect speciation history. Evolution 2020; 75:231-244. [PMID: 33078844 DOI: 10.1111/evo.14111] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 10/07/2020] [Indexed: 12/14/2022]
Abstract
Montane cloud forests are areas of high endemism, and are one of the more vulnerable terrestrial ecosystems to climate change. Thus, understanding how they both contribute to the generation of biodiversity, and will respond to ongoing climate change, are important and related challenges. The widely accepted model for montane cloud forest dynamics involves upslope forcing of their range limits with global climate warming. However, limited climate data provides some support for an alternative model, where range limits are forced downslope with climate warming. Testing between these two models is challenging, due to the inherent limitations of climate and pollen records. We overcome this with an alternative source of historical information, testing between competing model predictions using genomic data and demographic analyses for a species of beetle tightly associated to an oceanic island cloud forest. Results unequivocally support the alternative model: populations that were isolated at higher elevation peaks during the Last Glacial Maximum are now in contact and hybridizing at lower elevations. Our results suggest that genomic data are a rich source of information to further understand how montane cloud forest biodiversity originates, and how it is likely to be impacted by ongoing climate change.
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Affiliation(s)
- Antonia Salces-Castellano
- Island Ecology and Evolution Research Group, Institute of Natural Products and Agrobiology (IPNA-CSIC), La Laguna, 38206, Spain.,School of Doctoral and Postgraduate Studies, University of La Laguna, La Laguna, 38200, Spain
| | - Sean Stankowski
- Institute of Science and Technology, Klosterneuburg, 3400, Austria.,Department of Animal and Plant Sciences, University of Sheffield, Sheffield, S102TN, United Kingdom
| | - Paula Arribas
- Island Ecology and Evolution Research Group, Institute of Natural Products and Agrobiology (IPNA-CSIC), La Laguna, 38206, Spain
| | - Jairo Patiño
- Department of Botany, Ecology, and Plant Physiology, University of La Laguna, La Laguna, 38071, Spain
| | - Dirk N Karger
- Department - Dynamic Macroecology, Swiss Federal Research Institute WSL, Birmensdorf, 8903, Switzerland
| | - Roger Butlin
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, S102TN, United Kingdom.,Department of Marine Sciences, University of Gothenburg, Gothenburg, 40530, Sweden
| | - Brent C Emerson
- Island Ecology and Evolution Research Group, Institute of Natural Products and Agrobiology (IPNA-CSIC), La Laguna, 38206, Spain
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12
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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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13
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Royer AM, Waite-Himmelwright J, Smith CI. Strong Selection Against Early Generation Hybrids in Joshua Tree Hybrid Zone Not Explained by Pollinators Alone. FRONTIERS IN PLANT SCIENCE 2020; 11:640. [PMID: 32528500 PMCID: PMC7264850 DOI: 10.3389/fpls.2020.00640] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2020] [Accepted: 04/24/2020] [Indexed: 05/07/2023]
Abstract
Coevolution frequently plays an important role in diversification, but the role of obligate pollination mutualisms in the maintenance of hybrid zones has rarely been investigated. Like most members of the genus Yucca, the two species of Joshua tree (Yucca brevifolia and Yucca jaegeriana) are involved in a tightly coevolved mutualism with yucca moths. There is strong evidence of a history of coevolution between Joshua trees and their moth pollinators. We use a geographic clines approach in the Joshua tree hybrid zone to ask if selection by the moths may currently contribute to maintaining separation between these species. We compare genomic, phenotypic, and pollinator frequency clines to test whether pollinators maintain the hybrid zone or follow it as passive participants. The results reveal dramatic overlapping genomic and pollinator clines, consistent with a narrow hybrid zone maintained by strong selection. Wider phenotypic clines and a chloroplast genomic cline displaced opposite the expected direction suggest that pollinators are not the main source of selection maintaining the hybrid zone. Rather, it seems that high levels of reproductive isolation, likely acting through multiple barriers and involving many parts of the genome, keep the hybrid zone narrow.
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Affiliation(s)
- Anne M. Royer
- Biology Department, The University of Scranton, Scranton, PA, United States
- *Correspondence: Anne M. Royer,
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14
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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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15
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Wong ELY, Nevado B, Osborne OG, Papadopulos AST, Bridle JR, Hiscock SJ, Filatov DA. Strong divergent selection at multiple loci in two closely related species of ragworts adapted to high and low elevations on Mount Etna. Mol Ecol 2019; 29:394-412. [PMID: 31793091 DOI: 10.1111/mec.15319] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 11/28/2019] [Accepted: 11/28/2019] [Indexed: 12/20/2022]
Abstract
Recently diverged species present particularly informative systems for studying speciation and maintenance of genetic divergence in the face of gene flow. We investigated speciation in two closely related Senecio species, S. aethnensis and S. chrysanthemifolius, which grow at high and low elevations, respectively, on Mount Etna, Sicily and form a hybrid zone at intermediate elevations. We used a newly generated genome-wide single nucleotide polymorphism (SNP) dataset from 192 individuals collected over 18 localities along an elevational gradient to reconstruct the likely history of speciation, identify highly differentiated SNPs, and estimate the strength of divergent selection. We found that speciation in this system involved heterogeneous and bidirectional gene flow along the genome, and species experienced marked population size changes in the past. Furthermore, we identified highly-differentiated SNPs between the species, some of which are located in genes potentially involved in ecological differences between species (such as photosynthesis and UV response). We analysed the shape of these SNPs' allele frequency clines along the elevational gradient. These clines show significantly variable coincidence and concordance, indicative of the presence of multifarious selective forces. Selection against hybrids is estimated to be very strong (0.16-0.78) and one of the highest reported in literature. The combination of strong cumulative selection across the genome and previously identified intrinsic incompatibilities probably work together to maintain the genetic and phenotypic differentiation between these species - pointing to the importance of considering both intrinsic and extrinsic factors when studying divergence and speciation.
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Affiliation(s)
- Edgar L Y Wong
- Department of Plant Sciences, University of Oxford, Oxford, UK
| | - Bruno Nevado
- Department of Plant Sciences, University of Oxford, Oxford, UK
| | - Owen G Osborne
- Department of Plant Sciences, University of Oxford, Oxford, UK
| | | | - Jon R Bridle
- School of Biological Sciences, University of Bristol, Bristol, UK
| | - Simon J Hiscock
- Department of Plant Sciences, University of Oxford, Oxford, UK
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16
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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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17
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Wang S, Rohwer S, Delmore K, Irwin DE. Cross-decades stability of an avian hybrid zone. J Evol Biol 2019; 32:1242-1251. [PMID: 31430391 DOI: 10.1111/jeb.13524] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 08/06/2019] [Accepted: 08/13/2019] [Indexed: 01/04/2023]
Abstract
Hybrid zones are particularly valuable for understanding the evolution of partial reproductive isolation between differentiated populations. An increasing number of hybrid zones have been inferred to move over time, but in most such cases zone movement has not been tested with long-term genomic data. The hybrid zone between Townsend's Warblers (Setophaga townsendi) and Hermit Warblers (S. occidentalis) in the Washington Cascades was previously inferred to be moving from northern S. townsendi southwards towards S. occidentalis, based on plumage and behavioural patterns as well as a 2000-km genetic wake of hermit mitochondrial DNA (mtDNA) in coastal Townsend's Warblers. We directly tested whether hybrid zone position has changed over 2-3 decades by tracking plumage, mtDNA and nuclear genomic variation across the hybrid zone over two sampling periods (1987-94 and 2015-16). Surprisingly, there was no significant movement in genomic or plumage cline centres between the two time periods. Plumage cline widths were narrower than expected by neutral diffusion, consistent with a 'tension zone' model, in which selection against hybrids is balanced by movement of parental forms into the zone. Our results indicate that this hybrid zone is either stable in its location or moving at a rate that is not detectable over 2-3 decades. Despite considerable gene flow, the stable clines in multiple phenotypic and genotypic characters over decades suggest evolutionary stability of this young pair of sister species, allowing divergence to continue. We propose a novel biogeographic scenario to explain these patterns: rather than the hybrid zone having moved thousands of kilometres to its current position, inland Townsend's met coastal Hermit Warbler populations along a broad front of the British Columbia and Alaska coast and hybridization led to replacement of the Hermit Warbler plumage with Townsend's Warbler plumage patterns along this coastline. Hence, hybrid zones along British Columbia and Alaska moved only a short distance from the inland to the coast, whereas the Hermit Warbler phenotype appears stable in Washington and further south. This case provides an example of the complex biogeographic processes that have led to the distribution of current phenotypes within and among closely related species.
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Affiliation(s)
- Silu Wang
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada
| | - Sievert Rohwer
- Department of Biology and Burke Museum, University of Washington, Seattle, WA, USA
| | - Kira Delmore
- Department of Biology, Texas A & M, College Station, TX, USA
| | - Darren E Irwin
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada
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