1
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Leal JL, Milesi P, Hodková E, Zhou Q, James J, Eklund DM, Pyhäjärvi T, Salojärvi J, Lascoux M. Complex Polyploids: Origins, Genomic Composition, and Role of Introgressed Alleles. Syst Biol 2024; 73:392-418. [PMID: 38613229 PMCID: PMC11282369 DOI: 10.1093/sysbio/syae012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 12/18/2023] [Accepted: 03/28/2024] [Indexed: 04/14/2024] Open
Abstract
Introgression allows polyploid species to acquire new genomic content from diploid progenitors or from other unrelated diploid or polyploid lineages, contributing to genetic diversity and facilitating adaptive allele discovery. In some cases, high levels of introgression elicit the replacement of large numbers of alleles inherited from the polyploid's ancestral species, profoundly reshaping the polyploid's genomic composition. In such complex polyploids, it is often difficult to determine which taxa were the progenitor species and which taxa provided additional introgressive blocks through subsequent hybridization. Here, we use population-level genomic data to reconstruct the phylogenetic history of Betula pubescens (downy birch), a tetraploid species often assumed to be of allopolyploid origin and which is known to hybridize with at least four other birch species. This was achieved by modeling polyploidization and introgression events under the multispecies coalescent and then using an approximate Bayesian computation rejection algorithm to evaluate and compare competing polyploidization models. We provide evidence that B. pubescens is the outcome of an autoploid genome doubling event in the common ancestor of B. pendula and its extant sister species, B. platyphylla, that took place approximately 178,000-188,000 generations ago. Extensive hybridization with B. pendula, B. nana, and B. humilis followed in the aftermath of autopolyploidization, with the relative contribution of each of these species to the B. pubescens genome varying markedly across the species' range. Functional analysis of B. pubescens loci containing alleles introgressed from B. nana identified multiple genes involved in climate adaptation, while loci containing alleles derived from B. humilis revealed several genes involved in the regulation of meiotic stability and pollen viability in plant species.
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Affiliation(s)
- J Luis Leal
- Plant Ecology and Evolution, Department of Ecology and Genetics, Uppsala University, Norbyvägen 18D, 75236 Uppsala, Sweden
| | - Pascal Milesi
- Plant Ecology and Evolution, Department of Ecology and Genetics, Uppsala University, Norbyvägen 18D, 75236 Uppsala, Sweden
- Science for Life Laboratory (SciLifeLab), Uppsala University, 75237 Uppsala, Sweden
| | - Eva Hodková
- Plant Ecology and Evolution, Department of Ecology and Genetics, Uppsala University, Norbyvägen 18D, 75236 Uppsala, Sweden
- Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Kamýcká 129, 16521 Prague, Czech Republic
| | - Qiujie Zhou
- Plant Ecology and Evolution, Department of Ecology and Genetics, Uppsala University, Norbyvägen 18D, 75236 Uppsala, Sweden
| | - Jennifer James
- Plant Ecology and Evolution, Department of Ecology and Genetics, Uppsala University, Norbyvägen 18D, 75236 Uppsala, Sweden
| | - D Magnus Eklund
- Physiology and Environmental Toxicology, Department of Organismal Biology, Uppsala University, Norbyvägen 18A, 75236 Uppsala, Sweden
| | - Tanja Pyhäjärvi
- Organismal and Evolutionary Biology Research Program, Faculty of Biological and Environmental Sciences, and Viikki Plant Science Centre, University of Helsinki, P.O. Box 65 (Viikinkaari 1), 00014 Helsinki, Finland
- Department of Forest Sciences, University of Helsinki, 00014 Helsinki, Finland
| | - Jarkko Salojärvi
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
- Organismal and Evolutionary Biology Research Program, Faculty of Biological and Environmental Sciences, and Viikki Plant Science Centre, University of Helsinki, P.O. Box 65 (Viikinkaari 1), 00014 Helsinki, Finland
| | - Martin Lascoux
- Plant Ecology and Evolution, Department of Ecology and Genetics, Uppsala University, Norbyvägen 18D, 75236 Uppsala, Sweden
- Science for Life Laboratory (SciLifeLab), Uppsala University, 75237 Uppsala, Sweden
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2
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Rancilhac L, Enbody ED, Harris R, Saitoh T, Irestedt M, Liu Y, Lei F, Andersson L, Alström P. Introgression Underlies Phylogenetic Uncertainty But Not Parallel Plumage Evolution in a Recent Songbird Radiation. Syst Biol 2024; 73:12-25. [PMID: 37801684 PMCID: PMC11129591 DOI: 10.1093/sysbio/syad062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 09/11/2023] [Accepted: 10/05/2023] [Indexed: 10/08/2023] Open
Abstract
Instances of parallel phenotypic evolution offer great opportunities to understand the evolutionary processes underlying phenotypic changes. However, confirming parallel phenotypic evolution and studying its causes requires a robust phylogenetic framework. One such example is the "black-and-white wagtails," a group of 5 species in the songbird genus Motacilla: 1 species, Motacilla alba, shows wide intra-specific plumage variation, while the 4r others form 2 pairs of very similar-looking species (M. aguimp + M. samveasnae and M. grandis + M. maderaspatensis, respectively). However, the 2 species in each of these pairs were not recovered as sisters in previous phylogenetic inferences. Their relationships varied depending on the markers used, suggesting that gene tree heterogeneity might have hampered accurate phylogenetic inference. Here, we use whole genome resequencing data to explore the phylogenetic relationships within this group, with a special emphasis on characterizing the extent of gene tree heterogeneity and its underlying causes. We first used multispecies coalescent methods to generate a "complete evidence" phylogenetic hypothesis based on genome-wide variants, while accounting for incomplete lineage sorting (ILS) and introgression. We then investigated the variation in phylogenetic signal across the genome to quantify the extent of discordance across genomic regions and test its underlying causes. We found that wagtail genomes are mosaics of regions supporting variable genealogies, because of ILS and inter-specific introgression. The most common topology across the genome, supporting M. alba and M. aguimp as sister species, appears to be influenced by ancient introgression. Additionally, we inferred another ancient introgression event, between M. alba and M. grandis. By combining results from multiple analyses, we propose a phylogenetic network for the black-and-white wagtails that confirms that similar phenotypes evolved in non-sister lineages, supporting parallel plumage evolution. Furthermore, the inferred reticulations do not connect species with similar plumage coloration, suggesting that introgression does not underlie parallel plumage evolution in this group. Our results demonstrate the importance of investing genome-wide patterns of gene tree heterogeneity to help understand the mechanisms underlying phenotypic evolution. [Gene tree heterogeneity; incomplete lineage sorting; introgression; parallel evolution; phylogenomics; plumage evolution; wagtails.].
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Affiliation(s)
- Loïs Rancilhac
- Animal Ecology, Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18 D, 752 36 Uppsala, Sweden
| | - Erik D Enbody
- Department of Medical Biochemistry and Microbiology, Uppsala University, 751 23 Uppsala, Sweden
- Biomolecular Engineering, University of California, 95064 Santa Cruz, CA, USA
| | - Rebecca Harris
- Department of Biology, University of Washington, Seattle, WA 98105, USA
| | - Takema Saitoh
- Yamashina Institute for Ornithology, 115 Konoyama, Abiko, Chiba 270-1145, Japan
| | - Martin Irestedt
- Department of Bioinformatics and Genetics, Swedish Museum of Natural History, P.O. Box 50007, 104 05 Stockholm, Sweden
| | - Yang Liu
- State Key Laboratory of Biocontrol, School of Ecology, Sun Yat-sen University, Shenzhen 518107, China
| | - Fumin Lei
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, 100101 Beijing, China
| | - Leif Andersson
- Department of Medical Biochemistry and Microbiology, Uppsala University, 751 23 Uppsala, Sweden
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, TX 77843, USA
| | - Per Alström
- Animal Ecology, Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18 D, 752 36 Uppsala, Sweden
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, 100101 Beijing, China
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3
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Dean LL, Whiting JR, Jones FC, MacColl ADC. Reproductive isolation in a three-way contact zone. Mol Ecol 2024; 33:e17275. [PMID: 38235507 DOI: 10.1111/mec.17275] [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: 09/19/2023] [Revised: 01/05/2024] [Accepted: 01/10/2024] [Indexed: 01/19/2024]
Abstract
Contact zones between divergent forms within a species provide insight into the role of gene flow in adaptation and speciation. Previous work has focused on contact zones involving only two divergent forms, but in nature, many more than two populations may overlap simultaneously and experience gene flow. Patterns of introgression in wild populations are, therefore, likely much more complicated than is often assumed. We begin to address this gap in current knowledge by investigating patterns of divergence and introgression across a complex natural contact zone. We use phenotypic and genomic data to confirm the existence of a three-way contact zone among divergent freshwater resident, saltwater resident and saltwater migratory three-spined stickleback (Gasterosteus aculeatus) on the island of North Uist, Scottish Western Isles. We find evidence for hybridization, mostly between saltwater resident and saltwater migratory forms. Despite hybridization, genomic analyses reveal pairwise islands of divergence between all forms that are maintained across the contact zone. Genomic cline analyses also provide evidence for selection and/or hybrid incompatibilities in divergent regions. Divergent genomic regions occur across multiple chromosomes and involve many known adaptive loci and several chromosomal inversions. We also identify distinct immune gene expression profiles between forms, but no evidence for transgressive expression in hybrids. Our results suggest that reproductive isolation is maintained in this three-way contact zone, despite some hybridization, and that reduced recombination in chromosomal inversions may play an important role in maintaining this isolation.
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Affiliation(s)
- Laura L Dean
- School of Life Sciences, University of Nottingham, Nottingham, UK
| | - James R Whiting
- School of Life Sciences, University of Nottingham, Nottingham, UK
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
| | - Felicity C Jones
- Friedrich Miescher Laboratory of the Max Planck Society, Tübingen, Germany
- Groningen Institute for Evolutionary Life Sciences (GELIFES), University of Groningen, Groningen, The Netherlands
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4
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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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5
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Enbody ED, Sendell-Price AT, Sprehn CG, Rubin CJ, Visscher PM, Grant BR, Grant PR, Andersson L. Community-wide genome sequencing reveals 30 years of Darwin's finch evolution. Science 2023; 381:eadf6218. [PMID: 37769091 DOI: 10.1126/science.adf6218] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 08/22/2023] [Indexed: 09/30/2023]
Abstract
A fundamental goal in evolutionary biology is to understand the genetic architecture of adaptive traits. Using whole-genome data of 3955 of Darwin's finches on the Galápagos Island of Daphne Major, we identified six loci of large effect that explain 45% of the variation in the highly heritable beak size of Geospiza fortis, a key ecological trait. The major locus is a supergene comprising four genes. Abrupt changes in allele frequencies at the loci accompanied a strong change in beak size caused by natural selection during a drought. A gradual change in Geospiza scandens occurred across 30 years as a result of introgressive hybridization with G. fortis. This study shows how a few loci with large effect on a fitness-related trait contribute to the genetic potential for rapid adaptive radiation.
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Affiliation(s)
- Erik D Enbody
- Department of Medical Biochemistry and Microbiology, Uppsala University, Box 582, 751 23 Uppsala, Sweden
| | - Ashley T Sendell-Price
- Department of Medical Biochemistry and Microbiology, Uppsala University, Box 582, 751 23 Uppsala, Sweden
| | - C Grace Sprehn
- Department of Medical Biochemistry and Microbiology, Uppsala University, Box 582, 751 23 Uppsala, Sweden
| | - Carl-Johan Rubin
- Department of Medical Biochemistry and Microbiology, Uppsala University, Box 582, 751 23 Uppsala, Sweden
| | - Peter M Visscher
- Institute for Molecular Bioscience, The University of Queensland, 306 Carmody Rd., St. Lucia QLD 4072, Australia
| | - B Rosemary Grant
- Department of Ecology and Evolutionary Biology, Princeton University, 106A Guyot Hall, Princeton, NJ 08544, USA
| | - Peter R Grant
- Department of Ecology and Evolutionary Biology, Princeton University, 106A Guyot Hall, Princeton, NJ 08544, USA
| | - Leif Andersson
- Department of Medical Biochemistry and Microbiology, Uppsala University, Box 582, 751 23 Uppsala, Sweden
- Department of Veterinary Integrative Biosciences, Texas A&M University, 402 Raymond Stotzer Pkwy Building 2, College Station, TX 77843, USA
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6
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Tukhbatullin A, Ermakov O, Kapustina S, Starikov V, Tambovtseva V, Titov S, Brandler O. Surrounded by Kindred: Spermophilus major Hybridization with Other Spermophilus Species in Space and Time. BIOLOGY 2023; 12:880. [PMID: 37372163 DOI: 10.3390/biology12060880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 06/05/2023] [Accepted: 06/15/2023] [Indexed: 06/29/2023]
Abstract
Among the numerous described cases of hybridization in mammals, the most intriguing are (a) cases of introgressive hybridization deeply affecting the evolutionary history of species, and (b) models involving not a pair of species but a multi-species complex. Therefore, the hybridization history of the russet ground squirrel Spermophilus major, whose range has repeatedly changed due to climatic fluctuations and now borders the ranges of four related species, is of great interest. The main aims of this study were to determine the direction and intensity of gene introgression, the spatial depth of the infiltration of extraneous genes into the S. major range, and to refine the hypothesis of the hybridogenic replacement of mitochondrial genomes in the studied group. Using phylogenetic analysis of the variability of mitochondrial (CR, cytb) and nuclear (SmcY, BGN, PRKCI, c-myc, i6p53) markers, we determined the contribution of neighboring species to the S. major genome. We showed that 36% of S. major individuals had extraneous alleles. All peripheral species that were in contact with S. major contributed towards its genetic variability. We also proposed a hypothesis for the sequence and localization of serial hybridization events. Our assessment of the S. major genome implications of introgression highlights the importance of implementing conservation measures to protect this species.
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Affiliation(s)
- Andrey Tukhbatullin
- Koltzov Institute of Developmental Biology, Russian Academy of Sciences, Vavilova Str. 26, Moscow 119334, Russia
| | - Oleg Ermakov
- Faculty of Physics, Mathematics and Natural Sciences, Belinsky Institute of Teacher Education, Penza State University, Lermontov Str. 37, Penza 440026, Russia
| | - Svetlana Kapustina
- Koltzov Institute of Developmental Biology, Russian Academy of Sciences, Vavilova Str. 26, Moscow 119334, Russia
| | - Vladimir Starikov
- Department of Biology and Biotechnology, Institute of Natural and Technical Sciences, Surgut State University, Lenin Avenue 1, Surgut 628412, Russia
| | - Valentina Tambovtseva
- Koltzov Institute of Developmental Biology, Russian Academy of Sciences, Vavilova Str. 26, Moscow 119334, Russia
| | - Sergey Titov
- Faculty of Physics, Mathematics and Natural Sciences, Belinsky Institute of Teacher Education, Penza State University, Lermontov Str. 37, Penza 440026, Russia
| | - Oleg Brandler
- Koltzov Institute of Developmental Biology, Russian Academy of Sciences, Vavilova Str. 26, Moscow 119334, Russia
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7
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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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8
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Pauers MJ, Grudnowski JA. Female preferences for conspecific males indicate reproductive isolation between sympatric
Labeotropheus
Ahl from Lake Malaŵi. Ethology 2022. [DOI: 10.1111/eth.13282] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Michael J. Pauers
- Section of Vertebrate Zoology Milwaukee Public Museum Milwaukee Wisconsin USA
- Department of Mathematics and Natural Science University of Wisconsin‐Milwaukee at Waukesha Waukesha Wisconsin USA
- School of Freshwater Science University of Wisconsin‐Milwaukee Waukesha Wisconsin USA
| | - Jacob A. Grudnowski
- Department of Mathematics and Natural Science University of Wisconsin‐Milwaukee at Waukesha Waukesha Wisconsin USA
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9
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Buck R, Flores-Rentería L. The Syngameon Enigma. PLANTS (BASEL, SWITZERLAND) 2022; 11:plants11070895. [PMID: 35406874 PMCID: PMC9002738 DOI: 10.3390/plants11070895] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 03/21/2022] [Accepted: 03/25/2022] [Indexed: 05/17/2023]
Abstract
Despite their evolutionary relevance, multispecies networks or syngameons are rarely reported in the literature. Discovering how syngameons form and how they are maintained can give insight into processes such as adaptive radiations, island colonizations, and the creation of new hybrid lineages. Understanding these complex hybridization networks is even more pressing with anthropogenic climate change, as syngameons may have unique synergistic properties that will allow participating species to persist. The formation of a syngameon is not insurmountable, as several ways for a syngameon to form have been proposed, depending mostly on the magnitude and frequency of gene flow events, as well as the relatedness of its participants. Episodic hybridization with small amounts of introgression may keep syngameons stable and protect their participants from any detrimental effects of gene flow. As genomic sequencing becomes cheaper and more species are included in studies, the number of known syngameons is expected to increase. Syngameons must be considered in conservation efforts as the extinction of one participating species may have detrimental effects on the survival of all other species in the network.
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10
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Zheng W, Yan LJ, Burgess KS, Luo YH, Zou JY, Qin HT, Wang JH, Gao LM. Natural hybridization among three Rhododendron species (Ericaceae) revealed by morphological and genomic evidence. BMC PLANT BIOLOGY 2021; 21:529. [PMID: 34763662 PMCID: PMC8582147 DOI: 10.1186/s12870-021-03312-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Accepted: 11/02/2021] [Indexed: 06/08/2023]
Abstract
BACKGROUND Natural hybridization can influence the adaptive response to selection and accelerate species diversification. Understanding the composition and structure of hybrid zones may elucidate patterns of hybridization processes that are important to the formation and maintenance of species, especially for taxa that have experienced rapidly adaptive radiation. Here, we used morphological traits, ddRAD-seq and plastid DNA sequence data to investigate the structure of a Rhododendron hybrid zone and uncover the hybridization patterns among three sympatric and closely related species. RESULTS Our results show that the hybrid zone is complex, where bi-directional hybridization takes place among the three sympatric parental species: R. spinuliferum, R. scabrifolium, and R. spiciferum. Hybrids between R. spinuliferum and R. spiciferum (R. ×duclouxii) comprise multiple hybrid classes and a high proportion of F1 generation hybrids, while a novel hybrid taxon between R. spinuliferum and R. scabrifolium dominated the F2 generation, but no backcross individuals were detected. The hybrid zone showed basically coincident patterns of population structure between genomic and morphological data. CONCLUSIONS Natural hybridization exists among the three Rhododendron species in the hybrid zone, although patterns of hybrid formation vary between hybrid taxa, which may result in different evolutionary outcomes. This study represents a unique opportunity to dissect the ecological and evolutionary mechanisms associated with adaptive radiation of Rhododendron species in a biodiversity hotspot.
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Affiliation(s)
- Wei Zheng
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, 650201, Kunming, Yunnan, China
- University of Chinese Academy of Sciences, 10049, Beijing, China
| | - Li-Jun Yan
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, 650201, Kunming, Yunnan, China
- University of Chinese Academy of Sciences, 10049, Beijing, China
- College of Vocational and Technical Education, Yunnan Normal University, 650092, Kunming, Yunnan, China
| | - Kevin S Burgess
- Department of Biology, Columbus State University, University System of Georgia, 31907-5645, Columbus, GA, USA
| | - Ya-Huang Luo
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, 650201, Kunming, Yunnan, China
| | - Jia-Yun Zou
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, 650201, Kunming, Yunnan, China
- University of Chinese Academy of Sciences, 10049, Beijing, China
| | - Han-Tao Qin
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, 650201, Kunming, Yunnan, China
- University of Chinese Academy of Sciences, 10049, Beijing, China
| | - Ji-Hua Wang
- The Flower Research Institute, Yunnan Academy of Agricultural Sciences, 650205, Kunming, China.
| | - Lian-Ming Gao
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, 650201, Kunming, Yunnan, China.
- Lijiang Forest Biodiversity National Observation and Research Station, Kunming Institute of Botany, Chinese Academy of Sciences, 674100, Lijiang, Yunnan, China.
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11
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Enbody ED, Sprehn CG, Abzhanov A, Bi H, Dobreva MP, Osborne OG, Rubin CJ, Grant PR, Grant BR, Andersson L. A multispecies BCO2 beak color polymorphism in the Darwin's finch radiation. Curr Biol 2021; 31:5597-5604.e7. [PMID: 34687609 DOI: 10.1016/j.cub.2021.09.085] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Revised: 08/25/2021] [Accepted: 09/29/2021] [Indexed: 10/20/2022]
Abstract
Carotenoid-based polymorphisms are widespread in populations of birds, fish, and reptiles,1 but generally little is known about the factors affecting their maintenance in populations.2 We report a combined field and molecular-genetic investigation of a nestling beak color polymorphism in Darwin's finches. Beaks are pink or yellow, and yellow is recessive.3 Here we show that the polymorphism arose in the Galápagos half a million years ago through a mutation associated with regulatory change in the BCO2 gene and is shared by 14 descendant species. The polymorphism is probably a balanced polymorphism, maintained by ecological selection associated with survival and diet. In cactus finches, the frequency of the yellow genotype is correlated with cactus fruit abundance and greater hatching success and may be altered by introgressive hybridization. Polymorphisms that are hidden as adults, as here, may be far more common than is currently recognized, and contribute to diversification in ways that are yet to be discovered.
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Affiliation(s)
- Erik D Enbody
- Department of Medical Biochemistry and Microbiology, Uppsala University, SE-751 23 Uppsala, Sweden.
| | - C Grace Sprehn
- Department of Medical Biochemistry and Microbiology, Uppsala University, SE-751 23 Uppsala, Sweden
| | - Arhat Abzhanov
- Department of Life Sciences, Imperial College London, Silwood Park Campus, SL5 7PY Ascot, UK
| | - Huijuan Bi
- Department of Medical Biochemistry and Microbiology, Uppsala University, SE-751 23 Uppsala, Sweden
| | - Mariya P Dobreva
- Department of Life Sciences, Imperial College London, Silwood Park Campus, SL5 7PY Ascot, UK
| | - Owen G Osborne
- School of Natural Sciences, Bangor University, Environment Centre Wales, Deiniol Road, Bangor LL57 2UW, UK
| | - Carl-Johan Rubin
- Department of Medical Biochemistry and Microbiology, Uppsala University, SE-751 23 Uppsala, Sweden
| | - Peter R Grant
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA
| | - B Rosemary Grant
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA
| | - Leif Andersson
- Department of Medical Biochemistry and Microbiology, Uppsala University, SE-751 23 Uppsala, Sweden; Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, 75007 Uppsala, Sweden; Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, TX 77843-4458, USA.
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12
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Abstract
Many species of plants, animals, and microorganisms exchange genes well after the point of evolutionary divergence at which taxonomists recognize them as species. Genomes contain signatures of past gene exchange and, in some cases, they reveal a legacy of lineages that no longer exist. But genomic data are not available for many organisms, and particularly problematic for reconstructing and interpreting evolutionary history are communities that have been depleted by extinctions. For these, morphology may substitute for genes, as exemplified by the history of Darwin's finches on the Galápagos islands of Floreana and San Cristóbal. Darwin and companions collected seven specimens of a uniquely large form of Geospiza magnirostris in 1835. The populations became extinct in the next few decades, partly due to destruction of Opuntia cactus by introduced goats, whereas Geospiza fortis has persisted to the present. We used measurements of large samples of G. fortis collected for museums in the period 1891 to 1906 to test for unusually large variances and skewed distributions of beak and body size resulting from introgression. We found strong evidence of hybridization on Floreana but not on San Cristóbal. The skew is in the direction of the absent G. magnirostris We estimate introgression influenced 6% of the frequency distribution that was eroded by selection after G. magnirostris became extinct on these islands. The genetic residuum of an extinct species in an extant one has implications for its future evolution, as well as for a conservation program of reintroductions in extinction-depleted communities.
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13
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Justen H, Kimmitt AA, Delmore KE. Estimating hybridization rates in the wild: Easier said than done? Evolution 2021; 75:2137-2144. [PMID: 32820532 DOI: 10.1111/evo.14082] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 08/06/2020] [Accepted: 08/10/2020] [Indexed: 11/30/2022]
Abstract
Hybridization has important effects on the evolutionary trajectories of natural populations but estimates of this process in the wild and at the individual-level are lacking. Justyn et al. attempted to fill this gap using the citizen science database eBird but there are limitations to this approach. Here, we outline and directly test these limitations using literature searches, case studies, and a comparison between eBird and Birds of North America (BNA), a database that documents hybridization using the scientific literature. We use a hybrid zone between Lazuli and Indigo buntings to highlight the importance of considering geographic range when estimating rates of hybridization and two literature searches to show the importance of considering cryptic hybrids (those that cannot be identified using phenotypic traits) when quantifying these rates. We also use BNA and a case study of hybrid White-faced and Glossy Ibises to show that citizen scientists are underreporting hybrids compared with experts. Justyn et al. highlighted an important gap in the literature, but their results likely represent the lower limit of hybridization between birds and a more nuanced interpretation of their results (e.g., considering extrinsic postzygotic selection) is needed.
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Affiliation(s)
- Hannah Justen
- Department of Biology, Texas A&M University, College Station, Texas
| | | | - Kira E Delmore
- Department of Biology, Texas A&M University, College Station, Texas
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14
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Lavretsky P, Wilson RE, Talbot SL, Sonsthagen SA. Phylogenomics reveals ancient and contemporary gene flow contributing to the evolutionary history of sea ducks (Tribe Mergini). Mol Phylogenet Evol 2021; 161:107164. [PMID: 33798675 DOI: 10.1016/j.ympev.2021.107164] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 02/05/2021] [Accepted: 03/25/2021] [Indexed: 12/26/2022]
Abstract
Insight into complex evolutionary histories continues to build through broad comparative phylogenomic and population genomic studies. In particular, there is a need to understand the extent and scale that gene flow contributes to standing genomic diversity and the role introgression has played in evolutionary processes such as hybrid speciation. Here, we investigate the evolutionary history of the Mergini tribe (sea ducks) by coupling multi-species comparisons with phylogenomic analyses of thousands of nuclear ddRAD-seq loci, including Z-sex chromosome and autosomal linked loci, and the mitogenome assayed across all extant sea duck species in North America. All sea duck species are strongly structured across all sampled marker types (pair-wise species ΦST > 0.2), with clear genetic assignments of individuals to their respective species, and phylogenetic relationships recapitulate known relationships. Despite strong species integrity, we identify at least 18 putative hybrids; with all but one being late generational backcrosses. Most interesting, we provide the first evidence that an ancestral gene flow event between long-tailed ducks (Clangula hyemalis) and true Eiders (Somateria spp.) not only moved genetic material into the former species, but likely generated a novel species - the Steller's eider (Polysticta stelleri) - via hybrid speciation. Despite generally low contemporary levels of gene flow, we conclude that hybridization has and continues to be an important process that shifts novel genetic variation between species within the tribe Mergini. Finally, we outline methods that permit researchers to contrast genomic patterns of contemporary versus ancestral gene flow when attempting to reconstruct potentially complex evolutionary histories.
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Affiliation(s)
- Philip Lavretsky
- Department of Biological Sciences, University of Texas at El Paso, El Paso, TX 79668, USA; US Geological Survey, Alaska Science Center, 4210 University Dr., Anchorage, AK 99508, USA.
| | - Robert E Wilson
- US Geological Survey, Alaska Science Center, 4210 University Dr., Anchorage, AK 99508, USA
| | - Sandra L Talbot
- US Geological Survey, Alaska Science Center, 4210 University Dr., Anchorage, AK 99508, USA
| | - Sarah A Sonsthagen
- US Geological Survey, Alaska Science Center, 4210 University Dr., Anchorage, AK 99508, USA
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15
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Toews DPL, Kramer GR, Jones AW, Brennan CL, Cloud BE, Andersen DE, Lovette IJ, Streby H. Genomic identification of intergeneric hybrids in New World wood-warblers (Aves: Parulidae). Biol J Linn Soc Lond 2020. [DOI: 10.1093/biolinnean/blaa085] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
AbstractThe documentation of hybrids between distantly related taxa can illustrate an initial step to explain how genes might move between species that do not exhibit complete reproductive isolation. In birds, some of the most phylogenetically distant hybrid combinations occur between genera. Traditionally, morphological and plumage characters have been used to assign the identity of the parental species of a putative hybrid, although recently, nuclear introns also have been used. Here, we demonstrate how high-throughput short-read DNA sequence data can be used to identify the parentage of a putative intergeneric hybrid, in this case between a blue-winged warbler (Vermivora cyanoptera) and a cerulean warbler (Setophaga cerulea). This hybrid had mitochondrial DNA of a cerulean warbler, indicating the maternal parent. For hundreds of single nucleotide polymorphisms within six regions of the nuclear genome that differentiate blue-winged warblers and golden-winged warblers (Vermivora chrysoptera), the hybrid had roughly equal ancestry assignment to blue-winged and cerulean warblers, suggesting a blue-winged warbler as the paternal parent species and demonstrating that this was a first generation (F1) hybrid between these species. Unlike other recently characterized intergeneric warbler hybrids, this individual hybrid learned to song match its maternal parent species, suggesting that it might have been the result of an extra-pair mating and raised in a cerulean warbler nest.
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Affiliation(s)
- David P L Toews
- Department of Biology, Pennsylvania State University, State College, PA, USA
| | - Gunnar R Kramer
- Department of Environmental Sciences, University of Toledo, Toledo, OH, USA
| | | | | | - Benjamin E Cloud
- Department of Biology, University of Kentucky, Lexington, KY, USA
| | - David E Andersen
- US Geological Survey, Minnesota Cooperative Fish and Wildlife Research Unit, University of Minnesota, St Paul, MN, USA
| | - Irby J Lovette
- Cornell Lab of Ornithology, Cornell University, Ithaca, NY, USA
| | - Henry Streby
- Department of Environmental Sciences, University of Toledo, Toledo, OH, USA
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