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Quintero Melecio E, Rico Y, Lira Noriega A, González Rodríguez A. Molecular evidence and ecological niche modeling reveal an extensive hybrid zone among three Bursera species (section Bullockia). PLoS One 2021; 16:e0260382. [PMID: 34797901 PMCID: PMC8604287 DOI: 10.1371/journal.pone.0260382] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 11/08/2021] [Indexed: 12/27/2022] Open
Abstract
The genus Bursera, includes ~100 shrub and trees species in tropical dry forests with its center of diversification and endemism in Mexico. Morphologically intermediate individuals have commonly been observed in Mexican Bursera in areas where closely related species coexist. These individuals are assumed to result from interspecific hybridization, but no molecular evidence has supported their hybrid origins. This study aimed to investigate the existence of interspecific hybridization among three Mexican Bursera species (Bullockia section: B. cuneata, B. palmeri and B. bipinnata) from nine populations based on DNA sequences (three nuclear and four chloroplast regions) and ecological niche modeling for three past and two future scenario projections. Results from the only two polymorphic nuclear regions (PEPC, ETS) supported the hybrid origin of morphologically intermediate individuals and revealed that B. cuneata and B. bipinnata are the parental species that are genetically closer to the putative hybrids. Ecological niche modeling accurately predicted the occurrence of putative hybrid populations and showed a potential hybrid zone extending in a larger area (74,000 km2) than previously thought. Paleo-reconstructions showed a potential hybrid zone existing from the Last Glacial Maximum (~ 21 kya) that has increased since the late Holocene to the present. Future ecological niche projections show an increment of suitability of the potential hybrid zone for 2050 and 2070 relative to the present. Hybrid zone changes responded mostly to an increase in elevational ranges. Our study provides the first insight of an extensive hybrid zone among three Mexican Bursera species based on molecular data and ecological niche modeling.
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Affiliation(s)
- Eduardo Quintero Melecio
- Red de Diversidad Biológica del Occidente Mexicano, Centro Regional del Bajío, Instituto de Ecología, A.C., Pátzcuaro, Michoacán, Mexico
| | - Yessica Rico
- Red de Diversidad Biológica del Occidente Mexicano, Centro Regional del Bajío, Instituto de Ecología, A.C., Pátzcuaro, Michoacán, Mexico
- * E-mail:
| | - Andrés Lira Noriega
- Red de Estudios Moleculares Avanzados, Instituto de Ecología, A.C., Xalapa, Veracruz, Mexico
- CONACyT, Ciudad de México, Mexico
| | - Antonio González Rodríguez
- Laboratorio de Genética de la Conservación, Instituto de Investigaciones en Ecosistemas, Universidad Nacional Autónoma de México, Morelia, Michoacán, Mexico
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Maxwell LM, Walsh J, Olsen BJ, Kovach AI. Patterns of introgression vary within an avian hybrid zone. BMC Ecol Evol 2021; 21:14. [PMID: 33509089 PMCID: PMC7853311 DOI: 10.1186/s12862-021-01749-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 01/20/2021] [Indexed: 12/29/2022] Open
Abstract
Background Exploring hybrid zone dynamics at different spatial scales allows for better understanding of local factors that influence hybrid zone structure. In this study, we tested hypotheses about drivers of introgression at two spatial scales within the Saltmarsh Sparrow (Ammospiza caudacuta) and Nelson’s Sparrow (A. nelsoni) hybrid zone. Specifically, we evaluated the influence of neutral demographic processes (relative species abundance), natural selection (exogenous environmental factors and genetic incompatibilities), and sexual selection (assortative mating) in this mosaic hybrid zone. By intensively sampling adults (n = 218) and chicks (n = 326) at two geographically proximate locations in the center of the hybrid zone, we determined patterns of introgression on a fine scale across sites of differing habitat. We made broadscale comparisons of patterns from the center with those of prior studies in the southern edge of the hybrid zone. Results A panel of fixed SNPs (135) identified from ddRAD sequencing was used to calculate a hybrid index and determine genotypic composition/admixture level of the populations. Another panel of polymorphic SNPs (589) was used to assign paternity and reconstruct mating pairs to test for sexual selection. On a broad-scale, patterns of introgression were not explained by random mating within marshes. We found high rates of back-crossing and similarly low rates of recent-generation (F1/F2) hybrids in the center and south of the zone. Offspring genotypic proportions did not meet those expected from random mating within the parental genotypic distribution. Additionally, we observed half as many F1/F2 hybrid female adults than nestlings, while respective male groups showed no difference, in support of Haldane’s Rule. The observed proportion of interspecific mating was lower than expected when accounting for mate availability, indicating assortative mating was limiting widespread hybridization. On a fine spatial scale, we found variation in the relative influence of neutral and selective forces between inland and coastal habitats, with the smaller, inland marsh influenced primarily by neutral demographic processes, and the expansive, coastal marsh experiencing higher selective pressures in the form of natural (exogenous and endogenous) and sexual selection. Conclusions Multiple drivers of introgression, including neutral and selective pressures (exogenous, endogenous, and sexual selection), are structuring this hybrid zone, and their relative influence is site and context-dependent.
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Affiliation(s)
- Logan M Maxwell
- Department of Natural Resources and the Environment, University of New Hampshire, Durham, NH, USA
| | - Jennifer Walsh
- Department of Natural Resources and the Environment, University of New Hampshire, Durham, NH, USA.,Fuller Evolutionary Biology Program, Cornell Laboratory of Ornithology, Ithaca, NY, 14850, USA
| | - Brian J Olsen
- School of Biology & Ecology, University of Maine, Orono, ME, USA
| | - Adrienne I Kovach
- Department of Natural Resources and the Environment, University of New Hampshire, Durham, NH, USA.
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Tisshaw K, Freeland J, Dorken M. Salinity, not genetic incompatibilities, limits the establishment of the invasive hybrid cattail Typha × glauca in coastal wetlands. Ecol Evol 2020; 10:12091-12103. [PMID: 33209272 PMCID: PMC7663983 DOI: 10.1002/ece3.6831] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 08/31/2020] [Accepted: 09/03/2020] [Indexed: 11/08/2022] Open
Abstract
Hybrids of a single pair of parent species can be much more common in some geographical regions than in others. The reasons for this are not well understood, but could help explain processes such as species diversification or the range expansion of invasive hybrids. The widespread cattails Typha latifolia and T. angustifolia seldom hybridize in some parts of their range, but in other areas produce the dominant hybrid T. × glauca. We used a combination of field and greenhouse experiments to investigate why T. × glauca has invaded wetlands in the Laurentian Great Lakes region of southern Ontario, Canada, but is much less common in the coastal wetlands of Nova Scotia (NS) in eastern Canada. One potentially important environmental difference between these two regions is salinity. We therefore tested three hypotheses: (1) T. latifolia and T. angustifolia in NS are genetically incompatible; (2) the germination or growth of T. × glauca is reduced by salinity; and (3) T. latifolia, a main competitor of T. × glauca, is locally adapted to saline conditions in NS. Our experiments showed that NS T. latifolia and T. angustifolia are genetically compatible, and that saline conditions do not impede growth of hybrid plants. However, we also found that under conditions of high salinity, germination rates of hybrid seeds were substantially lower than those of NS T. latifolia. In addition, germination rates of NS T. latifolia were higher than those of Ontario T. latifolia, suggesting local adaptation to salinity in coastal wetlands. This study adds to the growing body of literature which identifies the important roles that local habitat and adaptation can play in the distributions and characteristics of hybrid zones.
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Affiliation(s)
- Kathryn Tisshaw
- Environmental and Life Sciences Graduate ProgramTrent UniversityPeterboroughONCanada
| | - Joanna Freeland
- Environmental and Life Sciences Graduate ProgramTrent UniversityPeterboroughONCanada
- Department of BiologyTrent UniversityPeterboroughONCanada
| | - Marcel Dorken
- Environmental and Life Sciences Graduate ProgramTrent UniversityPeterboroughONCanada
- Department of BiologyTrent UniversityPeterboroughONCanada
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Sefc KM, Mattersdorfer K, Hermann CM, Koblmüller S. Past lake shore dynamics explain present pattern of unidirectional introgression across a habitat barrier. HYDROBIOLOGIA 2019; 791:69-82. [PMID: 31186578 PMCID: PMC6557712 DOI: 10.1007/s10750-016-2791-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Introgression patterns between divergent lineages are often characterized by asymmetry in the direction and among-marker variation in the extent of gene flow, and therefore inform on the mechanisms involved in differentiation and speciation. In the present study, we test the hypothesis that unidirectional introgression between two phenotypically and genetically distinct lineages of the littoral, rock-dwelling cichlid fish Tropheus moorii across a wide sandy bay is linked to observed differences in mate preferences between the two lineages. This hypothesis predicts bi-directional nuclear gene flow and was rejected by congruent patterns of introgression in mtDNA, AFLP and microsatellite markers, with admixture confined to the populations west of the bay. This pattern can be explained on the basis of habitat changes in the course of lake level fluctuations, which first facilitated the development of a symmetric admixture zone including the area corresponding to the present sand bay and then shaped asymmetry by causing local extinctions and cessation of gene flow when this area became once more inhabitable. This conforms with previous assumptions that habitat dynamics are a primary determinant of population-level evolution in Tropheus. In this respect, Tropheus may be representative of species whose preferred habitat is subject to frequent re-structuring.
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Vázquez-Rosas-Landa M, Ponce-Soto GY, Eguiarte LE, Souza V. Comparative genomics of free-living Gammaproteobacteria: pathogenesis-related genes or interaction-related genes? Pathog Dis 2017; 75:3861975. [DOI: 10.1093/femspd/ftx059] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 06/02/2017] [Indexed: 12/25/2022] Open
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Temporal shifts in the saltmarsh–Nelson’s sparrow hybrid zone revealed by replicated demographic and genetic surveys. CONSERV GENET 2017. [DOI: 10.1007/s10592-016-0920-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Kingston SE, Parchman TL, Gompert Z, Buerkle CA, Braun MJ. Heterogeneity and concordance in locus‐specific differentiation and introgression between species of towhees. J Evol Biol 2017; 30:474-485. [DOI: 10.1111/jeb.13033] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2016] [Revised: 11/13/2016] [Accepted: 12/19/2016] [Indexed: 12/24/2022]
Affiliation(s)
- S. E. Kingston
- Program in Behavior, Ecology, Evolution, and Systematics University of Maryland College Park MD USA
- National Museum of Natural History Vertebrate Zoology Smithsonian Institution Washington DC USA
- Department of Biology and Coastal Studies Center Bowdoin College Brunswick ME USA
| | | | - Z. Gompert
- Department of Biology Utah State University Logan UT USA
| | - C. A. Buerkle
- Department of Botany University of Wyoming Laramie WY USA
| | - M. J. Braun
- Program in Behavior, Ecology, Evolution, and Systematics University of Maryland College Park MD USA
- National Museum of Natural History Vertebrate Zoology Smithsonian Institution Washington DC USA
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Hulsey CD, Bell KL, García-de-León FJ, Nice CC, Meyer A. Do relaxed selection and habitat temperature facilitate biased mitogenomic introgression in a narrowly endemic fish? Ecol Evol 2016; 6:3684-3698. [PMID: 27186367 PMCID: PMC4853310 DOI: 10.1002/ece3.2121] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Revised: 03/14/2016] [Accepted: 03/21/2016] [Indexed: 12/19/2022] Open
Abstract
Introgression might be exceptionally common during the evolution of narrowly endemic species. For instance, in the springs of the small and isolated Cuatro Ciénegas Valley, the mitogenome of the cichlid fish Herichthys cyanoguttatus could be rapidly introgressing into populations of the trophically polymorphic H. minckleyi. We used a combination of genetic and environmental data to examine the factors associated with this mitochondrial introgression. A reduced representation library of over 6220 single nucleotide polymorphisms (SNPs) from the nuclear genome showed that mitochondrial introgression into H. minckleyi is biased relative to the amount of nuclear introgression. SNP assignment probabilities also indicated that cichlids with more hybrid ancestry are not more commonly female providing no support for asymmetric backcrossing or hybrid‐induced sex‐ratio distortion in generating the bias in mitochondrial introgression. Smaller effective population size in H. minckleyi inferred from the SNPs coupled with sequences of all 13 mitochondrial proteins suggests that relaxed selection on the mitogenome could be facilitating the introgression of “H. cyanoguttatus” haplotypes. Additionally, we showed that springs with colder temperatures had greater amounts of mitochondrial introgression from H. cyanoguttatus. Relaxed selection in H. minckleyi coupled with temperature‐related molecular adaptation could be facilitating mitogenomic introgression into H. minckleyi.
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Affiliation(s)
| | - Katherine L Bell
- Department of Biology Texas State University, San Marcos 601 University Drive 78666 San Marcos Texas
| | - Francisco J García-de-León
- Laboratorio de Genética para la Conservación Centro de Investigaciones Biológicas del Noroeste PO Box 128 La Paz B.C.S. Mexico
| | - Chris C Nice
- Department of Biology Texas State University, San Marcos 601 University Drive 78666 San Marcos Texas
| | - Axel Meyer
- Department of Biology University of Konstanz Universitätstraße 10 78457 Konstanz Germany
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Walsh J, Rowe RJ, Olsen BJ, Shriver WG, Kovach AI. Genotype-environment associations support a mosaic hybrid zone between two tidal marsh birds. Ecol Evol 2015; 6:279-94. [PMID: 26811792 PMCID: PMC4716509 DOI: 10.1002/ece3.1864] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Revised: 10/29/2015] [Accepted: 11/02/2015] [Indexed: 01/19/2023] Open
Abstract
Local environmental features can shape hybrid zone dynamics when hybrids are bounded by ecotones or when patchily distributed habitat types lead to a corresponding mosaic of genotypes. We investigated the role of marsh-level characteristics in shaping a hybrid zone between two recently diverged avian taxa - Saltmarsh (Ammodramus caudacutus) and Nelson's (A. nelsoni) sparrows. These species occupy different niches where allopatric, with caudacutus restricted to coastal marshes and nelsoni found in a broader array of wetland and grassland habitats and co-occur in tidal marshes in sympatry. We determined the influence of habitat types on the distribution of pure and hybrid sparrows and assessed the degree of overlap in the ecological niche of each taxon. To do this, we sampled and genotyped 305 sparrows from 34 marshes across the hybrid zone and from adjacent regions. We used linear regression to test for associations between marsh characteristics and the distribution of pure and admixed sparrows. We found a positive correlation between genotype and environmental variables with a patchy distribution of genotypes and habitats across the hybrid zone. Ecological niche models suggest that the hybrid niche was more similar to that of A. nelsoni and habitat suitability was influenced strongly by distance from coastline. Our results support a mosaic model of hybrid zone maintenance, suggesting a role for local environmental features in shaping the distribution and frequency of pure species and hybrids across space.
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Affiliation(s)
- Jennifer Walsh
- Department of Natural Resources and the Environment University of New Hampshire Durham New Hampshire
| | - Rebecca J Rowe
- Department of Natural Resources and the Environment University of New Hampshire Durham New Hampshire
| | - Brian J Olsen
- School of Biology and Ecology University of Maine Orono Maine
| | - W Gregory Shriver
- Department of Entomology and Wildlife Ecology University of Delaware Newark Delaware
| | - Adrienne I Kovach
- Department of Natural Resources and the Environment University of New Hampshire Durham New Hampshire
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Carson EW, Souza V, Espinosa-Pérez H, Turner TF. Mitochondrial DNA Diversity and Phylogeography ofLucania interiorisInform Biodiversity Conservation in the Cuatro Ciénegas Basin, México. WEST N AM NATURALIST 2015. [DOI: 10.3398/064.075.0208] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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11
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Litsios G, Salamin N. Hybridisation and diversification in the adaptive radiation of clownfishes. BMC Evol Biol 2014; 14:245. [PMID: 25433367 PMCID: PMC4264551 DOI: 10.1186/s12862-014-0245-5] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Accepted: 11/17/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The importance of hybridisation during species diversification has long been debated among evolutionary biologists. It is increasingly recognised that hybridisation events occurred during the evolutionary history of numerous species, especially during the early stages of adaptive radiation. We study the effect of hybridisation on diversification in the clownfishes, a clade of coral reef fish that diversified through an adaptive radiation process. While two species of clownfish are likely to have been described from hybrid specimens, the occurrence and effect of hybridisation on the clade diversification is yet unknown. RESULTS We generate sequences of three mitochondrial genes to complete an existing dataset of nuclear sequences and document cytonuclear discordance at a node, which shows a drastic increase of diversification rate. Then, using a tree-based jack-knife method, we identify clownfish species likely stemming from hybridisation events. Finally, we use molecular cloning and identify the putative parental species of four clownfish specimens that display the morphological characteristics of hybrids. CONCLUSIONS Our results show that consistently with the syngameon hypothesis, hybridisation events are linked with a burst of diversification in the clownfishes. Moreover, several recently diverged clownfish lineages likely originated through hybridisation, which indicates that diversification, catalysed by hybridisation events, may still be happening.
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Affiliation(s)
- Glenn Litsios
- Department of Ecology and Evolution, Biophore, University of Lausanne, 1015, Lausanne, Switzerland.
- Swiss Institute of Bioinformatics, Génopode, Quartier Sorge, 1015, Lausanne, Switzerland.
| | - Nicolas Salamin
- Department of Ecology and Evolution, Biophore, University of Lausanne, 1015, Lausanne, Switzerland.
- Swiss Institute of Bioinformatics, Génopode, Quartier Sorge, 1015, Lausanne, Switzerland.
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Li C, Gowan S, Anil A, Beck BH, Thongda W, Kucuktas H, Kaltenboeck L, Peatman E. Discovery and validation of gene-linked diagnostic SNP markers for assessing hybridization between Largemouth bass (Micropterus salmoides) and Florida bass (M. floridanus). Mol Ecol Resour 2014; 15:395-404. [DOI: 10.1111/1755-0998.12308] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Revised: 07/17/2014] [Accepted: 07/18/2014] [Indexed: 11/28/2022]
Affiliation(s)
- Chao Li
- School of Fisheries; Aquaculture and Aquatic Sciences; Auburn University; Auburn AL 36849 USA
| | - Spencer Gowan
- School of Fisheries; Aquaculture and Aquatic Sciences; Auburn University; Auburn AL 36849 USA
| | - Ammu Anil
- School of Fisheries; Aquaculture and Aquatic Sciences; Auburn University; Auburn AL 36849 USA
| | - Benjamin H. Beck
- United States Department of Agriculture; Agricultural Research Service; Stuttgart National Aquaculture Research Center; Stuttgart AR 72160 USA
| | - Wilawan Thongda
- School of Fisheries; Aquaculture and Aquatic Sciences; Auburn University; Auburn AL 36849 USA
| | - Huseyin Kucuktas
- School of Fisheries; Aquaculture and Aquatic Sciences; Auburn University; Auburn AL 36849 USA
| | - Ludmilla Kaltenboeck
- School of Fisheries; Aquaculture and Aquatic Sciences; Auburn University; Auburn AL 36849 USA
| | - Eric Peatman
- School of Fisheries; Aquaculture and Aquatic Sciences; Auburn University; Auburn AL 36849 USA
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Carson EW, De la Maza-Benignos M, de Lourdes Lozano-Vilano M, Vela-Valladares L, Banda-Villanueva I, Turner TF. Conservation genetic assessment of the critically endangered Julimes pupfish, Cyprinodon julimes. CONSERV GENET 2013. [DOI: 10.1007/s10592-013-0548-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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14
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Kingston SE, Navarro-Sigüenza AG, García-Trejo EA, Vázquez-Miranda H, Fagan WF, Braun MJ. Genetic differentiation and habitat connectivity across towhee hybrid zones in Mexico. Evol Ecol 2013. [DOI: 10.1007/s10682-013-9673-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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15
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Muto N, Kai Y, Noda T, Nakabo T. Extensive hybridization and associated geographic trends between two rockfishes Sebastes vulpes
and S. zonatus
(Teleostei: Scorpaeniformes: Sebastidae). J Evol Biol 2013; 26:1750-62. [DOI: 10.1111/jeb.12175] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Revised: 03/06/2013] [Accepted: 03/28/2013] [Indexed: 11/27/2022]
Affiliation(s)
- N. Muto
- Division of Applied Biosciences; Graduate School of Agriculture; Kyoto University c/o The Kyoto University Museum; Kyoto University; Sakyo Kyoto Japan
| | - Y. Kai
- Field Science Education and Research Centre; Maizuru Fisheries Research Station; Kyoto University; Maizuru Kyoto Japan
| | - T. Noda
- Tohoku National Fisheries Research Institute; Fisheries Research Agency; Miyako Iwate Japan
| | - T. Nakabo
- The Kyoto University Museum; Kyoto University; Sakyo Kyoto Japan
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Pritchard VL, Knutson VL, Lee M, Zieba J, Edmands S. Fitness and morphological outcomes of many generations of hybridization in the copepod Tigriopus californicus. J Evol Biol 2012; 26:416-33. [DOI: 10.1111/jeb.12060] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2012] [Revised: 10/23/2012] [Accepted: 10/24/2012] [Indexed: 12/27/2022]
Affiliation(s)
- V. L. Pritchard
- Department of Biological Sciences; University of Southern California; Los Angeles CA USA
| | - V. L. Knutson
- Department of Biological Sciences; University of Southern California; Los Angeles CA USA
| | - M. Lee
- Department of Biological Sciences; University of Southern California; Los Angeles CA USA
| | - J. Zieba
- Department of Biological Sciences; University of Southern California; Los Angeles CA USA
| | - S. Edmands
- Department of Biological Sciences; University of Southern California; Los Angeles CA USA
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Diversity across Seasons of Culturable Pseudomonas from a Desiccation Lagoon in Cuatro Cienegas, Mexico. Int J Microbiol 2012; 2012:201389. [PMID: 23093963 PMCID: PMC3474248 DOI: 10.1155/2012/201389] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Accepted: 08/15/2012] [Indexed: 11/17/2022] Open
Abstract
Cuatro Cienegas basin (CCB) is a biodiversity reservoir within the Chihuahuan desert that includes several water systems subject to marked seasonality. While several studies have focused on biodiversity inventories, this is the first study that describes seasonal changes in diversity within the basin. We sampled Pseudomonas populations from a seasonally variable water system at four different sampling dates (August 2003, January 2004, January 2005, and August 2005). A total of 70 Pseudomonas isolates across seasons were obtained, genotyped by fingerprinting (BOX-PCR), and taxonomically characterized by 16S rDNA sequencing. We found 35 unique genotypes, and two numerically dominant lineages (16S rDNA sequences) that made up 64% of the sample: P. cuatrocienegasensis and P. otitidis. We did not recover genotypes across seasons, but lineages reoccurred across seasons; P. cuatrocienegasensis was isolated exclusively in winter, while P. otitidis was only recovered in summer. We statistically show that taxonomic identity of isolates is not independent of the sampling season, and that winter and summer populations are different. In addition to the genetic description of populations, we show exploratory measures of growth rates at different temperatures, suggesting physiological differences between populations. Altogether, the results indicate seasonal changes in diversity of free-living aquatic Pseudomonas populations from CCB.
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Cullingham CI, James PMA, Cooke JEK, Coltman DW. Characterizing the physical and genetic structure of the lodgepole pine × jack pine hybrid zone: mosaic structure and differential introgression. Evol Appl 2012; 5:879-91. [PMID: 23346232 PMCID: PMC3552405 DOI: 10.1111/j.1752-4571.2012.00266.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2012] [Accepted: 04/08/2012] [Indexed: 01/07/2023] Open
Abstract
Understanding the physical and genetic structure of hybrid zones can illuminate factors affecting their formation and stability. In north-central Alberta, lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia) and jack pine (Pinus banksiana Lamb) form a complex and poorly defined hybrid zone. Better knowledge of this zone is relevant, given the recent host expansion of mountain pine beetle into jack pine. We characterized the zone by genotyping 1998 lodgepole, jack pine, and hybrids from British Columbia, Alberta, Saskatchewan, Ontario, and Minnesota at 11 microsatellites. Using Bayesian algorithms, we calculated genetic ancestry and used this to model the relationship between species occurrence and environment. In addition, we analyzed the ancestry of hybrids to calculate the genetic contribution of lodgepole and jack pine. Finally, we measured the amount of gene flow between the pure species. We found the distribution of the pine classes is explained by environmental variables, and these distributions differ from classic distribution maps. Hybrid ancestry was biased toward lodgepole pine; however, gene flow between the two species was equal. The results of this study suggest that the hybrid zone is complex and influenced by environmental constraints. As a result of this analysis, range limits should be redefined.
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