1
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Bailey RI. Bayesian hybrid index and genomic cline estimation with the R package gghybrid. Mol Ecol Resour 2024; 24:e13910. [PMID: 38063369 DOI: 10.1111/1755-0998.13910] [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: 06/19/2023] [Revised: 11/15/2023] [Accepted: 11/24/2023] [Indexed: 01/12/2024]
Abstract
Admixture, the interbreeding of individuals from differentiated source populations, is now known to be a widespread phenomenon. Genomic studies of natural hybridisation can help to answer many questions on the impacts of admixture on adaptive evolution, reproductive isolation, and speciation. When a large variety of admixture proportions between two source populations exist, both geographic and genomic cline analysis are suitable methods for inferring biased, restricted or excessive gene flow at individual loci into the foreign genomic background, providing evidence for reproductive isolation, selection across an environmental transition, balancing selection, and adaptive introgression. Genomic cline analysis replaces geographic location with genome-wide hybrid index and is therefore useable in circumstances that violate geographic cline assumptions. Here, I introduce gghybrid, an R package for simple and flexible Bayesian estimation of Buerkle's hybrid index and Fitzpatrick's logit-logistic genomic clines using bi-allelic data, suitable for both small and large datasets. gghybrid allows any ploidy and uses Structure input file format. It has separate functions for hybrid index and cline estimation, treating each individual and locus respectively as an independent analysis, making it highly parallelisable. Admixture proportions from other software can alternatively be used in cline analysis, alongside parental allele frequencies. Parameters can be fixed and samples pooled for statistical model comparison with AIC or waic. Here, I describe the functions, pipeline, and statistical properties of gghybrid. Simulations reveal that model comparison with waic is preferred, and use of Bayesian posterior distributions and p values to select candidate non-null loci is problematic and should be avoided.
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Affiliation(s)
- Richard Ian Bailey
- Department of Ecology and Vertebrate Zoology, Faculty of Biology and Environmental Protection, University of Lodz, Łódź, Poland
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2
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Graham BA, Szabo I, Cicero C, Strickland D, Woods J, Coneybeare H, Dohms KM, Burg TM. Habitat and climate influence hybridization among three genetically distinct Canada jay (Perisoreus canadensis) morphotypes in an avian hybrid zone complex. Heredity (Edinb) 2023; 131:361-373. [PMID: 37813941 PMCID: PMC10674025 DOI: 10.1038/s41437-023-00652-3] [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: 04/21/2023] [Revised: 09/22/2023] [Accepted: 09/27/2023] [Indexed: 10/11/2023] Open
Abstract
Examining the frequency and distribution of hybrids across contact zones provide insights into the factors mediating hybridization. In this study, we examined the effect of habitat and climate on hybridization patterns for three phenotypically, genetically, and ecologically distinct groups of the Canada jay (Perisoreus canadensis) in a secondary contact zone in western North America. Additionally, we tested whether the frequency of hybridization involving the three groups (referred to as Boreal, Pacific and Rocky Mountain morphotypes) is similar across the hybrid zones or whether some pairs have hybridized more frequently than others. We reanalyzed microsatellite, mtDNA and plumage data, and new microsatellite and plumage data for 526 individuals to identify putative genetic and phenotypic hybrids. The genetically and phenotypically distinct groups are associated with different habitats and occupy distinct climate niches across the contact zone. Most putative genetic hybrids (86%) had Rocky Mountain ancestry. Hybrids were observed most commonly in intermediate climate niches and in habitats where Engelmann spruce (Picea engelmannii) overlaps broadly with boreal and subalpine tree species. Our finding that hybrids occupy intermediate climate niches relative to parental morphotypes matches patterns for other plant and animal species found in this region. This study demonstrates how habitat and climate influence hybridization patterns in areas of secondary contact and adds to the growing body of research on tri-species hybrid zones.
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Affiliation(s)
- B A Graham
- Department of Biological Sciences, University of Lethbridge, 4401 University Drive W, Lethbridge, AB, T1K 3M4, Canada.
| | - I Szabo
- Beaty Biodiversity Museum, University of British Columbia, 2212 Main Mall, Vancouver, BC, V6T 1Z4, Canada
| | - C Cicero
- Museum of Vertebrate Zoology, University of California, 3101 Valley Life Sciences Building, Berkeley, CA, 94720-3160, USA
| | - D Strickland
- 1063 Oxtongue Lake Road, Dwight, ON, P0A 1H0, Canada
| | - J Woods
- 1221 23rd Avenue SW, Salmon Arm, BC, V1E 0A9, Canada
| | - H Coneybeare
- 5210 Frederick Road, Armstrong, BC, V0E 1B4, Canada
| | - K M Dohms
- Canadian Wildlife Services, Environment and Climate Change Canada, 5421 Robertson Road, Delta, BC, V4K 3N2, Canada
| | - T M Burg
- Department of Biological Sciences, University of Lethbridge, 4401 University Drive W, Lethbridge, AB, T1K 3M4, Canada
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3
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Natola L, Seneviratne SS, Irwin D. Population genomics of an emergent tri-species hybrid zone. Mol Ecol 2022; 31:5356-5367. [PMID: 35951007 DOI: 10.1111/mec.16650] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2022] [Revised: 08/03/2022] [Accepted: 08/09/2022] [Indexed: 12/15/2022]
Abstract
Isolating barriers that drive speciation are commonly studied in the context of two-species hybrid zones. There is, however, evidence that more complex introgressive relationships are common in nature. Here, we use field observations and genomic analysis, including the sequencing and assembly of a novel reference genome, to study an emergent hybrid zone involving two colliding hybrid zones of three woodpecker species: red-breasted, red-naped, and yellow-bellied sapsuckers (Sphyrapicus ruber, S. nuchalis, and S. varius). Surveys of the area surrounding Prince George, British Columbia, Canada, show that all three species are sympatric, and Genotyping-by-Sequencing identifies hybrids from each species pair and birds with ancestry from all three species. Observations of phenotypes and genotypes of mated pairs provide evidence for assortative mating, though there is some heterospecific pairing. Hybridization is more extensive in this tri-species hybrid zone than in two di-species hybrid zones. However, there is no evidence of a hybrid swarm and admixture is constrained to contact zones, so we classify this region as a tension zone and invoke selection against hybrids as a likely mechanism maintaining species boundaries. Analysis of sapsucker age classes does not show disadvantages in hybrid survival to adulthood, so we speculate the selection upholding the tension zone may involve hybrid fecundity. Gene flow among all sapsuckers in di-species hybrid zones suggests introgression probably occurred before the formation of this tri-species hybrid zone, and might result from bridge hybridization, vagrancies, or other three-species interactions.
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Affiliation(s)
- Libby Natola
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada.,Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
| | - Sampath S Seneviratne
- Avian Sciences and Conservation, Department of Zoology, University of Colombo, Colombo, Sri Lanka
| | - Darren Irwin
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada.,Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
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4
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Campana MG, Hawkins MTR, Caballero S. Editorial: Assessing Biodiversity in the Phylogenomic Era. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.803188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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5
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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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6
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Caeiro-Dias G, Brelsford A, Kaliontzopoulou A, Meneses-Ribeiro M, Crochet PA, Pinho C. Variable levels of introgression between the endangered Podarcis carbonelli and highly divergent congeneric species. Heredity (Edinb) 2021; 126:463-476. [PMID: 33199832 PMCID: PMC8027454 DOI: 10.1038/s41437-020-00386-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 10/27/2020] [Accepted: 10/29/2020] [Indexed: 11/08/2022] Open
Abstract
Recent empirical studies have demonstrated that speciation with gene flow is more common than previously thought. From a conservation perspective, the potential negative effects of hybridization raise concerns on the genetic integrity of endangered species. However, introgressive hybridization has also been growingly recognized as a source of diversity and new advantageous alleles. Carbonell's wall lizard (Podarcis carbonelli) is an endangered species whose distribution overlaps with four other congeneric species. Our goal here was to determine whether P. carbonelli is completely reproductively isolated from its congeners and to evaluate the relevance of hybridization and interspecific gene flow for developing a conservation plan. We used restriction site associated DNA (RAD) sequencing to discover SNPs in samples from four contact zones between P. carbonelli and four other species. Principal component analysis, multilocus genotype assignment and interspecific heterozygosity suggest incomplete reproductive isolation and ongoing gene flow between species. However, hybridization dynamics vary across all pairs, suggesting complex interactions between multiple intrinsic and extrinsic barriers. Despite seemingly ubiquitous interspecific gene flow, we found evidence of strong reproductive isolation across most contact zones. Instead, indirect effects of hybridization like waste of reproductive effort in small isolated populations may be more problematic. Our results highlight the need to further evaluate the consequences of introgression for P. carbonelli, both on a geographic and genomic level and included in a comprehensive and urgently needed conservation plan. Besides, those findings will add important insights on the potential effects of hybridization and introgression for endangered species.
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Affiliation(s)
- Guilherme Caeiro-Dias
- Centro de Investigação em Biodiversidade e Recursos Genéticos, CIBIO/InBIO, Universidade do Porto, Vairão, Portugal.
- Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Porto, Portugal.
- CEFE, CNRS, Université de Montpellier, EPHE, IRD, Université Paul Valéry Montpellier 3, Montpellier, France.
| | - Alan Brelsford
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
- Biology Department, University of California Riverside, Riverside, CA, USA
| | - Antigoni Kaliontzopoulou
- Centro de Investigação em Biodiversidade e Recursos Genéticos, CIBIO/InBIO, Universidade do Porto, Vairão, Portugal
| | - Mariana Meneses-Ribeiro
- Centro de Investigação em Biodiversidade e Recursos Genéticos, CIBIO/InBIO, Universidade do Porto, Vairão, Portugal
| | - Pierre-André Crochet
- CEFE, CNRS, Université de Montpellier, EPHE, IRD, Université Paul Valéry Montpellier 3, Montpellier, France
| | - Catarina Pinho
- Centro de Investigação em Biodiversidade e Recursos Genéticos, CIBIO/InBIO, Universidade do Porto, Vairão, Portugal
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7
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Graham BA, Cicero C, Strickland D, Woods JG, Coneybeare H, Dohms KM, Szabo I, Burg TM. Cryptic genetic diversity and cytonuclear discordance characterize contact among Canada jay ( Perisoreus canadensis) morphotypes in western North America. Biol J Linn Soc Lond 2021. [DOI: 10.1093/biolinnean/blaa223] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Abstract
Three distinct Canada jay (Perisoreus canadensis) morphotypes with easily recognizable plumage traits come into contact in western North America. Recent work demonstrated high genetic structure across the species’ range; however, patterns of genetic variation in these contact zones remain unknown. We categorized 605 individuals into one of three morphotypes (Pacific, Rocky Mountain, and Boreal) based on plumage, and genotyped individuals at the mtDNA control region and 12 microsatellite loci to assess the extent of hybridization between morphotypes. Our data showed cryptic genetic diversity and high cytonuclear discordance among morphotypes within contact zones, which is likely the result of recent and historical admixture. The distributions of the Boreal and Pacific morphotypes each showed a strong association with a single, distinct genetic group, whereas the Rocky Mountain morphotype exhibited higher genetic diversity and was associated with multiple genotypes. Our analyses show the importance of considering both plumage and genetic traits when examining contact zones between closely related taxa. Finally the data presented in this study reaffirm that the Pacific morphotype is distinct from the Boreal and Rocky Mountain morphotypes based on genetic, phenotypic and ecological data, indicating that the Pacific morphotype should be re-elevated to a full species.
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Affiliation(s)
- Brendan A Graham
- Department of Biological Sciences, University of Lethbridge, Lethbridge, AB, Canada
| | - Carla Cicero
- Museum of Vertebrate Zoology, University of California, Berkeley, CA, USA
| | | | - John G Woods
- 41221 23rd Avenue SW, Salmon Arm, BC, V1E 0A9, Canada
| | | | - Kimberly M Dohms
- Canadian Wildlife Services, Environment and Climate Change Canada, Delta, BC, Canada
| | - Ildiko Szabo
- Beaty Biodiversity Museum, University of British Columbia, Vancouver, BC, Canada
| | - Theresa M Burg
- Department of Biological Sciences, University of Lethbridge, Lethbridge, AB, Canada
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8
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Irwin DE. Assortative Mating in Hybrid Zones Is Remarkably Ineffective in Promoting Speciation. Am Nat 2020; 195:E150-E167. [DOI: 10.1086/708529] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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9
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Recent introgression between Taiga Bean Goose and Tundra Bean Goose results in a largely homogeneous landscape of genetic differentiation. Heredity (Edinb) 2020; 125:73-84. [PMID: 32451423 PMCID: PMC7413267 DOI: 10.1038/s41437-020-0322-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 05/11/2020] [Accepted: 05/12/2020] [Indexed: 02/06/2023] Open
Abstract
Several studies have uncovered a highly heterogeneous landscape of genetic differentiation across the genomes of closely related species. Specifically, genetic differentiation is often concentrated in particular genomic regions (“islands of differentiation”) that might contain barrier loci contributing to reproductive isolation, whereas the rest of the genome is homogenized by introgression. Alternatively, linked selection can produce differentiation islands in allopatry without introgression. We explored the influence of introgression on the landscape of genetic differentiation in two hybridizing goose taxa: the Taiga Bean Goose (Anser fabalis) and the Tundra Bean Goose (A. serrirostris). We re-sequenced the whole genomes of 18 individuals (9 of each taxon) and, using a combination of population genomic summary statistics and demographic modeling, we reconstructed the evolutionary history of these birds. Next, we quantified the impact of introgression on the build-up and maintenance of genetic differentiation. We found evidence for a scenario of allopatric divergence (about 2.5 million years ago) followed by recent secondary contact (about 60,000 years ago). Subsequent introgression events led to high levels of gene flow, mainly from the Tundra Bean Goose into the Taiga Bean Goose. This scenario resulted in a largely undifferentiated genomic landscape (genome-wide FST = 0.033) with a few notable differentiation peaks that were scattered across chromosomes. The summary statistics indicated that some peaks might contain barrier loci while others arose in allopatry through linked selection. Finally, based on the low genetic differentiation, considerable morphological variation and incomplete reproductive isolation, we argue that the Taiga and the Tundra Bean Goose should be treated as subspecies.
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10
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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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11
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Ebersbach J, Posso-Terranova A, Bogdanowicz S, Gómez-Díaz M, García-González MX, Bolívar-García W, Andrés J. Complex patterns of differentiation and gene flow underly the divergence of aposematic phenotypes in Oophaga poison frogs. Mol Ecol 2020; 29:1944-1956. [PMID: 31971303 DOI: 10.1111/mec.15360] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 12/11/2019] [Accepted: 01/04/2020] [Indexed: 12/16/2022]
Abstract
Hybridization and introgression can have complex consequences for both species evolution and conservation. Here, we investigated the origin and characteristics of a putative hybrid zone between two South American poison dart frog species, Oophaga anchicayensis and the critically endangered Oophaga lehmanni, which are heavily sought after on the illegal pet market. Using a combination of phenotypic (49 traits) and genomic (ddRADseq) data, we found that the putative hybrids are morphologically distinct from their parental species and confirmed genomic signatures of admixture in these populations. Several lines of evidence (hybrid indices, interspecific hybrid heterozygosity, genomic clines, comparisons with simulated hybrids and demographic modelling) support the conclusion that these populations are not comprised of early-generation hybrids and thus, they probably did not arise as a result of illegal translocations associated with wildlife trafficking. Instead, they probably represent an independent lineage which has persisted through isolation and has only relatively recently re-established gene flow with both parental species. Furthermore, we detected signals of differential introgression from parental species into these hybrid populations which suggest relaxed stabilizing selection on these aposematic colour morphs, potentially via context-dependent female choice. These populations thus provide a fascinating window into the role of hybridization, isolation and female choice in the diversification of South American poison dart frogs. In addition, our results underline the importance of landscape conservation measures to protect, not only known localities of nominal species, but also the phenotypic and genomic variation harbored by admixed lineages which represent crucial repositories for the impressive diversity in this system.
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Affiliation(s)
- Jana Ebersbach
- Department of Biology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Andrés Posso-Terranova
- Department of Biology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.,Facultad de Ciencias Agropecuarias, Universidad Nacional de Colombia sede Palmira, Palmira, Colombia
| | - Steven Bogdanowicz
- Department of Ecology and Evolution, Cornell University, Ithaca, NY, USA
| | - Mónica Gómez-Díaz
- Research Group in Animal Ecology, Department of Biology, Universidad del Valle, Cali, Colombia
| | | | - Wilmar Bolívar-García
- Research Group in Animal Ecology, Department of Biology, Universidad del Valle, Cali, Colombia
| | - José Andrés
- Department of Biology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.,Department of Ecology and Evolution, Cornell University, Ithaca, NY, USA
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12
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Natola L, Burg TM. Population Genetics and Speciation of Yellow-Bellied, Red-Naped, and Red-Breasted Sapsuckers (Sphyrapicus varius, S. nuchalis, and S. ruber). J Hered 2019; 109:663-674. [PMID: 30010809 DOI: 10.1093/jhered/esy034] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 07/11/2018] [Indexed: 12/11/2022] Open
Abstract
The root of understanding speciation lies in determining the forces which drive it. In many closely-related species, including Sphyrapicus varius, S. nuchalis, and S. ruber, it is assumed that speciation occurred due to isolation in multiple Pleistocene refugia. We used genetic data from 457 samples at the control region (CR), cytochrome oxidase I (COI), and chromo-helicase DNA binding protein (CHD1Z) to examine range-wide population genetic structure and differentiation amongst these 3 species across each species' breeding range. In addition, we modeled these species' ecological niches for the Holocene (~6000 years ago), Last Glacial Maximum (~22000 years ago), and Last Interglacial (~120000-140000 years ago) to determine if Pleistocene glaciations could have contributed to allopatric distributions, therefore allowing these groups to differentiate. Population genetic data show a potential Pleistocene refugium in Haida Gwaii, an east-west split among S. varius, and low genetic differentiation within each species. Our CR data show some polyphyly, while COI and CHD1Z data show differentiation among species using composite genotypes. Ecological Niche Modeling shows a large amount of niche overlap at each time period suggesting that S. varius, S. nuchalis, and S. ruber may not have been completely allopatric, and these species likely had repeated intermittent contact. Our data support the growing body of research that suggests differentiation despite gene flow.
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Affiliation(s)
- Libby Natola
- Department of Biological Sciences, University of Lethbridge, Lethbridge, AB, Canada
| | - Theresa M Burg
- Department of Biological Sciences, University of Lethbridge, Lethbridge, AB, Canada
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13
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Billerman SM, Cicero C, Bowie RCK, Carling MD. Phenotypic and genetic introgression across a moving woodpecker hybrid zone. Mol Ecol 2019; 28:1692-1708. [DOI: 10.1111/mec.15043] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 01/22/2019] [Indexed: 01/05/2023]
Affiliation(s)
- Shawn M. Billerman
- Department of Zoology and Physiology University of Wyoming Laramie Wyoming
- Program in Ecology University of Wyoming Laramie Wyoming
| | - Carla Cicero
- Museum of Vertebrate Zoology University of California Berkeley California
| | - Rauri C. K. Bowie
- Museum of Vertebrate Zoology University of California Berkeley California
- Department of Integrative Biology University of California Berkeley California
| | - Matthew D. Carling
- Department of Zoology and Physiology University of Wyoming Laramie Wyoming
- Program in Ecology University of Wyoming Laramie Wyoming
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14
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Pulido-Santacruz P, Aleixo A, Weir JT. Morphologically cryptic Amazonian bird species pairs exhibit strong postzygotic reproductive isolation. Proc Biol Sci 2019. [PMID: 29514967 DOI: 10.1098/rspb.2017.2081] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
We possess limited understanding of how speciation unfolds in the most species-rich region of the planet-the Amazon basin. Hybrid zones provide valuable information on the evolution of reproductive isolation, but few studies of Amazonian vertebrate hybrid zones have rigorously examined the genome-wide underpinnings of reproductive isolation. We used genome-wide genetic datasets to show that two deeply diverged, but morphologically cryptic sister species of forest understorey birds show little evidence for prezygotic reproductive isolation, but substantial postzygotic isolation. Patterns of heterozygosity and hybrid index revealed that hybrid classes with heavily recombined genomes are rare and closely match simulations with high levels of selection against hybrids. Genomic and geographical clines exhibit a remarkable similarity across loci in cline centres, and have exceptionally narrow cline widths, suggesting that postzygotic isolation is driven by genetic incompatibilities at many loci, rather than a few loci of strong effect. We propose Amazonian understorey forest birds speciate slowly via gradual accumulation of postzygotic genetic incompatibilities, with prezygotic barriers playing a less important role. Our results suggest old, cryptic Amazonian taxa classified as subspecies could have substantial postzygotic isolation deserving species recognition and that species richness is likely to be substantially underestimated in Amazonia.
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Affiliation(s)
| | - Alexandre Aleixo
- Department of Zoology, Museu Paraense Emílio Goeldi, Belém, Brazil
| | - Jason T Weir
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Canada .,Department of Biological Sciences, University of Toronto Scarborough, Toronto, Canada
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15
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Mageski MM, Varela S, Roper JJ. Consequences of dispersal limitation and habitat fragmentation for the Brazilian heart-tongued frogs ( Phyllodytesspp.). AUSTRAL ECOL 2018. [DOI: 10.1111/aec.12591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Marcio Marques Mageski
- Programa de Pós-Graduação em Ecologia de Ecossistemas; Universidade Vila Velha; 29102-920 Vila Velha ES Brazil
| | - Sara Varela
- Museum für Naturkunde; Leibniz Institute for Evolution and Biodiversity Science; Berlin Germany
| | - James Joseph Roper
- Programa de Pós-Graduação em Ecologia de Ecossistemas; Universidade Vila Velha; 29102-920 Vila Velha ES Brazil
- Programa de Pós-Graduação em Ecologia e Conservação; Universidade Federal do Paraná; Curitiba PR Brazil
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16
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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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17
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Irwin DE. Sex chromosomes and speciation in birds and other ZW systems. Mol Ecol 2018; 27:3831-3851. [PMID: 29443419 DOI: 10.1111/mec.14537] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2017] [Revised: 02/03/2018] [Accepted: 02/06/2018] [Indexed: 01/01/2023]
Abstract
Theory and empirical patterns suggest a disproportionate role for sex chromosomes in evolution and speciation. Focusing on ZW sex determination (females ZW, males ZZ; the system in birds, many snakes, and lepidopterans), I review how evolutionary dynamics are expected to differ between the Z, W and the autosomes, discuss how these differences may lead to a greater role of the sex chromosomes in speciation and use data from birds to compare relative evolutionary rates of sex chromosomes and autosomes. Neutral mutations, partially or completely recessive beneficial mutations, and deleterious mutations under many conditions are expected to accumulate faster on the Z than on autosomes. Sexually antagonistic polymorphisms are expected to arise on the Z, raising the possibility of the spread of preference alleles. The faster accumulation of many types of mutations and the potential for complex evolutionary dynamics of sexually antagonistic traits and preferences contribute to a role for the Z chromosome in speciation. A quantitative comparison among a wide variety of bird species shows that the Z tends to have less within-population diversity and greater between-species differentiation than the autosomes, likely due to both adaptive evolution and a greater rate of fixation of deleterious alleles. The W chromosome also shows strong potential to be involved in speciation, in part because of its co-inheritance with the mitochondrial genome. While theory and empirical evidence suggest a disproportionate role for sex chromosomes in speciation, the importance of sex chromosomes is moderated by their small size compared to the whole genome.
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Affiliation(s)
- Darren E Irwin
- Department of Zoology and Biodiversity Research Centre, University of British Columbia, Vancouver, BC, Canada
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18
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Sung C, Bell KL, Nice CC, Martin NH. Integrating Bayesian genomic cline analyses and association mapping of morphological and ecological traits to dissect reproductive isolation and introgression in a Louisiana Iris hybrid zone. Mol Ecol 2018; 27:959-978. [DOI: 10.1111/mec.14481] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Accepted: 12/14/2017] [Indexed: 01/01/2023]
Affiliation(s)
- Cheng‐Jung Sung
- Population and Conservation Biology Program Department of Biology Texas State University San Marcos TX USA
| | - Katherine L. Bell
- Population and Conservation Biology Program Department of Biology Texas State University San Marcos TX USA
| | - Chris C. Nice
- Population and Conservation Biology Program Department of Biology Texas State University San Marcos TX USA
| | - Noland H. Martin
- Population and Conservation Biology Program Department of Biology Texas State University San Marcos TX USA
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19
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Blackburn GS, Brunet BMT, Muirhead K, Cusson M, Béliveau C, Levesque RC, Lumley LM, Sperling FAH. Distinct sources of gene flow produce contrasting population genetic dynamics at different range boundaries of aChoristoneurabudworm. Mol Ecol 2017; 26:6666-6684. [DOI: 10.1111/mec.14386] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 09/26/2017] [Accepted: 10/07/2017] [Indexed: 12/14/2022]
Affiliation(s)
- Gwylim S. Blackburn
- Department of Biological Sciences; CW405 Biosciences Centre; University of Alberta; Edmonton AB Canada
- Laurentian Forestry Centre; Natural Resources Canada; Canadian Forest Service; Quebec City QC Canada
- Institut de Biologie Intégrative et des Systèmes (IBIS); Université Laval; Québec QC Canada
| | - Bryan M. T. Brunet
- Department of Biological Sciences; CW405 Biosciences Centre; University of Alberta; Edmonton AB Canada
| | - Kevin Muirhead
- Department of Biological Sciences; CW405 Biosciences Centre; University of Alberta; Edmonton AB Canada
| | - Michel Cusson
- Laurentian Forestry Centre; Natural Resources Canada; Canadian Forest Service; Quebec City QC Canada
| | - Catherine Béliveau
- Laurentian Forestry Centre; Natural Resources Canada; Canadian Forest Service; Quebec City QC Canada
| | - Roger C. Levesque
- Institut de Biologie Intégrative et des Systèmes (IBIS); Université Laval; Québec QC Canada
| | - Lisa M. Lumley
- Department of Biological Sciences; CW405 Biosciences Centre; University of Alberta; Edmonton AB Canada
- Laurentian Forestry Centre; Natural Resources Canada; Canadian Forest Service; Quebec City QC Canada
| | - Felix A. H. Sperling
- Department of Biological Sciences; CW405 Biosciences Centre; University of Alberta; Edmonton AB Canada
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