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Soudi S, Jahani M, Todesco M, Owens GL, Bercovich N, Rieseberg LH, Yeaman S. Repeatability of adaptation in sunflowers reveals that genomic regions harbouring inversions also drive adaptation in species lacking an inversion. eLife 2023; 12:RP88604. [PMID: 38095362 PMCID: PMC10721221 DOI: 10.7554/elife.88604] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2023] Open
Abstract
Local adaptation commonly involves alleles of large effect, which experience fitness advantages when in positive linkage disequilibrium (LD). Because segregating inversions suppress recombination and facilitate the maintenance of LD between locally adapted loci, they are also commonly found to be associated with adaptive divergence. However, it is unclear what fraction of an adaptive response can be attributed to inversions and alleles of large effect, and whether the loci within an inversion could still drive adaptation in the absence of its recombination-suppressing effect. Here, we use genome-wide association studies to explore patterns of local adaptation in three species of sunflower: Helianthus annuus, Helianthus argophyllus, and Helianthus petiolaris, which each harbour a large number of species-specific inversions. We find evidence of significant genome-wide repeatability in signatures of association to phenotypes and environments, which are particularly enriched within regions of the genome harbouring an inversion in one species. This shows that while inversions may facilitate local adaptation, at least some of the loci can still harbour mutations that make substantial contributions without the benefit of recombination suppression in species lacking a segregating inversion. While a large number of genomic regions show evidence of repeated adaptation, most of the strongest signatures of association still tend to be species-specific, indicating substantial genotypic redundancy for local adaptation in these species.
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Affiliation(s)
- Shaghayegh Soudi
- Department of Biological Sciences, University of CalgaryCalgaryCanada
| | - Mojtaba Jahani
- Department of Biological Sciences, University of CalgaryCalgaryCanada
- Department of Botany, University of British ColumbiaVancouverCanada
| | - Marco Todesco
- Department of Botany, University of British ColumbiaVancouverCanada
- Michael Smith Laboratories, University of British ColumbiaVancouverCanada
- Irving K. Barber Faculty of Science, University of British Columbia OkanaganKelownaCanada
| | | | | | | | - Sam Yeaman
- Department of Biological Sciences, University of CalgaryCalgaryCanada
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2
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Makarenko MS, Azarin KV, Gavrilova VA. Mitogenomic Research of Silverleaf Sunflower ( Helianthus argophyllus) and Its Interspecific Hybrids. Curr Issues Mol Biol 2023; 45:4841-4849. [PMID: 37367057 DOI: 10.3390/cimb45060308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Revised: 05/28/2023] [Accepted: 05/30/2023] [Indexed: 06/28/2023] Open
Abstract
Interspecific hybridization is widespread for sunflowers, both in wild populations and commercial breeding. One of the most common species that can efficiently cross with Helianthus annuus is the Silverleaf sunflower-Helianthus argophyllus. The current study carried out structural and functional organization analyses of mitochondrial DNA in H. argophyllus and the interspecific hybrid, H. annuus (VIR114A line) × H. argophyllus. The complete mitogenome of H. argophyllus counts 300,843 bp, has a similar organization to the mitogenome of cultivated sunflower, and holds SNPs typical for wild sunflowers. RNA editing analysis predicted 484 sites in H. argophyllus mitochondrial CDS. The mitochondrial genome of the H. annuus × H. argophyllus hybrid is identical to the maternal line (VIR114A). We expected that significant rearrangements in the mitochondrial DNA of the hybrid would occur, due to the frequent recombination. However, the hybrid mitogenome lacks rearrangements, presumably due to the preservation of nuclear-cytoplasmic interaction paths.
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Affiliation(s)
- Maksim S Makarenko
- The Laboratory of Plant Genomics, The Institute for Information Transmission Problems, 127051 Moscow, Russia
| | - Kirill V Azarin
- The Laboratory of Molecular Genetics, Southern Federal University, 344006 Rostov-on-Don, Russia
| | - Vera A Gavrilova
- Oil and Fiber Crops Genetic Resources Department, The N.I. Vavilov All Russian Institute of Plant Genetic Resources, 190031 Saint Petersburg, Russia
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3
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Owens GL, Huang K, Todesco M, Rieseberg LH. Re-evaluating Homoploid Reticulate Evolution in Helianthus Sunflowers. Mol Biol Evol 2023; 40:6989481. [PMID: 36648104 PMCID: PMC9907532 DOI: 10.1093/molbev/msad013] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 01/03/2023] [Accepted: 01/11/2023] [Indexed: 01/18/2023] Open
Abstract
Sunflowers of the genus Helianthus are models for hybridization research and contain three of the best-studied examples of homoploid hybrid speciation. To understand a broader picture of hybridization within the annual sunflowers, we used whole-genome resequencing to conduct a phylogenomic analysis and test for gene flow between lineages. We find that all annual sunflower species tested have evidence of admixture, suggesting hybridization was common during the radiation of the genus. Support for the major species tree decreases with increasing recombination rate, consistent with hybridization and introgression contributing to discordant topologies. Admixture graphs found hybridization to be associated with the origins of the three putative hybrid species (Helianthus anomalus, Helianthus deserticola, and Helianthus paradoxus). However, the hybridization events are more ancient than suggested by previous work. Furthermore, H. anomalus and H. deserticola appear to have arisen from a single hybridization event involving an unexpected donor, rather than through multiple independent events as previously proposed. This means our results are consistent with, but not definitive proof of, two ancient independent homoploid hybrid speciation events in the genus. Using a broader data set that covers the whole Helianthus genus, including perennial species, we find that signals of introgression span the genus and beyond, suggesting highly divergent introgression and/or the sorting of ancient haplotypes. Thus, Helianthus can be viewed as a syngameon in which largely reproductively isolated species are linked together by occasional or frequent gene flow.
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Affiliation(s)
| | - Kaichi Huang
- Department of Botany and Beaty Biodiversity Center, University of British Columbia, Vancouver, BC, Canada
| | - Marco Todesco
- Department of Botany and Beaty Biodiversity Center, University of British Columbia, Vancouver, BC, Canada
| | - Loren H Rieseberg
- Department of Botany and Beaty Biodiversity Center, University of British Columbia, Vancouver, BC, Canada
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4
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Bieker VC, Battlay P, Petersen B, Sun X, Wilson J, Brealey JC, Bretagnolle F, Nurkowski K, Lee C, Barreiro FS, Owens GL, Lee JY, Kellner FL, van Boheeman L, Gopalakrishnan S, Gaudeul M, Mueller-Schaerer H, Lommen S, Karrer G, Chauvel B, Sun Y, Kostantinovic B, Dalén L, Poczai P, Rieseberg LH, Gilbert MTP, Hodgins KA, Martin MD. Uncovering the genomic basis of an extraordinary plant invasion. SCIENCE ADVANCES 2022; 8:eabo5115. [PMID: 36001672 PMCID: PMC9401624 DOI: 10.1126/sciadv.abo5115] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 07/11/2022] [Indexed: 05/31/2023]
Abstract
Invasive species are a key driver of the global biodiversity crisis, but the drivers of invasiveness, including the role of pathogens, remain debated. We investigated the genomic basis of invasiveness in Ambrosia artemisiifolia (common ragweed), introduced to Europe in the late 19th century, by resequencing 655 ragweed genomes, including 308 herbarium specimens collected up to 190 years ago. In invasive European populations, we found selection signatures in defense genes and lower prevalence of disease-inducing plant pathogens. Together with temporal changes in population structure associated with introgression from closely related Ambrosia species, escape from specific microbial enemies likely favored the plant's remarkable success as an invasive species.
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Affiliation(s)
- Vanessa C. Bieker
- Department of Natural History, NTNU University Museum, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Paul Battlay
- School of Biological Sciences, Monash University, Melbourne, Australia
| | - Bent Petersen
- Center for Evolutionary Hologenomics, GLOBE Institute, University of Copenhagen, Copenhagen, Denmark
- Centre of Excellence for Omics-Driven Computational Biodiscovery (COMBio), AIMST University, 08100 Kedah, Malaysia
| | - Xin Sun
- Department of Natural History, NTNU University Museum, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Jonathan Wilson
- School of Biological Sciences, Monash University, Melbourne, Australia
| | - Jaelle C. Brealey
- Department of Natural History, NTNU University Museum, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - François Bretagnolle
- UMR CNRS/uB 6282 Biogéosciences, Université de Bourgogne-Franche-Comté, Dijon, France
| | - Kristin Nurkowski
- School of Biological Sciences, Monash University, Melbourne, Australia
| | - Chris Lee
- School of Biological Sciences, Monash University, Melbourne, Australia
| | - Fátima Sánchez Barreiro
- Center for Evolutionary Hologenomics, GLOBE Institute, University of Copenhagen, Copenhagen, Denmark
| | | | - Jacqueline Y. Lee
- School of Biological Sciences, Monash University, Melbourne, Australia
| | - Fabian L. Kellner
- Department of Natural History, NTNU University Museum, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | | | - Shyam Gopalakrishnan
- Center for Evolutionary Hologenomics, GLOBE Institute, University of Copenhagen, Copenhagen, Denmark
| | - Myriam Gaudeul
- Institut de Systématique Evolution Biodiversité (ISYEB), Muséum National d’Histoire Naturelle, CNRS, SU, EPHE, UA, National Herbarium (P), 57 rue Cuvier, CP39, 75005 Paris, France
| | | | - Suzanne Lommen
- Department of Biology, University of Fribourg, Fribourg, Switzerland
- Institute of Biology, Section Plant Ecology and Phytochemistry, Leiden University, P.O. Box 9505, 2300 RA Leiden, Netherlands
- Koppert Biological Systems, Department R&D Macrobiology, Veilingweg 14, 2651 BE Berkel en Rodenrijs, Netherlands
| | - Gerhard Karrer
- Department of Integrative Biology and Biodiversity Research, University of Natural Resources and Life Sciences Vienna, Vienna, Austria
| | - Bruno Chauvel
- UMR Agroécologie, Institut Agro, INRAE, Univ. Bourgogne, Univ. Bourgogne-Franche-Comté, F-21000 Dijon, France
| | - Yan Sun
- College of Resources and Environment, Huazhong Agricultural University, Wuhan, China
| | - Bojan Kostantinovic
- Department of Environmental and Plant Protection, Faculty of Agriculture, University of Novi Sad, Novi Sad, Serbia
| | - Love Dalén
- Centre for Palaeogenetics, Stockholm, Sweden
- Department of Bioinformatics and Genetics, Swedish Museum of Natural History, Stockholm, Sweden
| | - Péter Poczai
- Botany Unit, Finnish Museum of Natural History, University of Helsinki, Helsinki, Finland
- Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
- Institute of Advanced Studies Kőszeg (iASK), Kőszeg, Hungary
| | - Loren H. Rieseberg
- Department of Botany and Biodiversity Research Centre, University of British Columbia, Vancouver, Canada
| | - M. Thomas P. Gilbert
- Department of Natural History, NTNU University Museum, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
- Center for Evolutionary Hologenomics, GLOBE Institute, University of Copenhagen, Copenhagen, Denmark
| | | | - Michael D. Martin
- Department of Natural History, NTNU University Museum, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
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5
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Yao X, Wang S, Wang Z, Li D, Jiang Q, Zhang Q, Gao L, Zhong C, Huang H, Liu Y. The genome sequencing and comparative analysis of a wild kiwifruit Actinidia eriantha. MOLECULAR HORTICULTURE 2022; 2:13. [PMID: 37789488 PMCID: PMC10515239 DOI: 10.1186/s43897-022-00034-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 04/18/2022] [Indexed: 10/05/2023]
Abstract
The current kiwifruit industry is mainly based on the cultivars derived from the species Actinidia chinensis (Ac) which may bring risks such as canker disease. Introgression of desired traits from wild relatives is an important method for improving kiwifruit cultivars. Actinidia eriantha (Ae) is a particularly important taxon used for hybridization or introgressive breeding of new kiwifruit cultivars because of its valued species-specific traits. Here, we assembled a chromosome-scale high-quality genome of a Ae sample which was directly collected from its wild populations. Our analysis revealed that 41.3% of the genome consists of repetitive elements, comparable to the percentage in Ac and Ae cultivar "White" genomes. The genomic structural variation, including the presence/absence-variation (PAV) of genes, is distinct between Ae and Ac, despite both sharing the same two kiwifruit-specific whole genome duplication (WGD) events. This suggests that a post-WGD divergence mechanism occurred during their evolution. We further investigated genes involved in ascorbic acid biosynthesis and disease-resistance of Ae, and we found introgressive genome could contribute to the complex relationship between Ae and other representative kiwifruit taxa. Collectively, the Ae genome offers valuable genetic resource to accelerate kiwifruit breeding applications.
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Affiliation(s)
- Xiaohong Yao
- Key Laboratory of Plant Germplasm Enhancement and Specially Agriculture, Wuhan Botanical Garden, the Chinese Academy of Sciences, Wuhan, 430074, China
| | - Shuaibin Wang
- Department of Bioinformatics, College of Life Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Zupeng Wang
- Key Laboratory of Plant Germplasm Enhancement and Specially Agriculture, Wuhan Botanical Garden, the Chinese Academy of Sciences, Wuhan, 430074, China
| | - Dawei Li
- Key Laboratory of Plant Germplasm Enhancement and Specially Agriculture, Wuhan Botanical Garden, the Chinese Academy of Sciences, Wuhan, 430074, China
| | - Quan Jiang
- Key Laboratory of Plant Germplasm Enhancement and Specially Agriculture, Wuhan Botanical Garden, the Chinese Academy of Sciences, Wuhan, 430074, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Qiong Zhang
- Key Laboratory of Plant Germplasm Enhancement and Specially Agriculture, Wuhan Botanical Garden, the Chinese Academy of Sciences, Wuhan, 430074, China
| | - Lei Gao
- Key Laboratory of Plant Germplasm Enhancement and Specially Agriculture, Wuhan Botanical Garden, the Chinese Academy of Sciences, Wuhan, 430074, China
| | - Caihong Zhong
- Key Laboratory of Plant Germplasm Enhancement and Specially Agriculture, Wuhan Botanical Garden, the Chinese Academy of Sciences, Wuhan, 430074, China
| | - Hongwen Huang
- Lushan Botanical Garden, Chinese Academy of Sciences, Jiujiang, 332900, China
| | - Yifei Liu
- College of Pharmacy, Hubei University of Chinese Medicine, Wuhan, 430065, China.
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6
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James ME, Arenas-Castro H, Groh JS, Allen SL, Engelstädter J, Ortiz-Barrientos D. Highly Replicated Evolution of Parapatric Ecotypes. Mol Biol Evol 2021; 38:4805-4821. [PMID: 34254128 PMCID: PMC8557401 DOI: 10.1093/molbev/msab207] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Parallel evolution of ecotypes occurs when selection independently drives the evolution of similar traits across similar environments. The multiple origins of ecotypes are often inferred based on a phylogeny that clusters populations according to geographic location and not by the environment they occupy. However, the use of phylogenies to infer parallel evolution in closely related populations is problematic because gene flow and incomplete lineage sorting can uncouple the genetic structure at neutral markers from the colonization history of populations. Here, we demonstrate multiple origins within ecotypes of an Australian wildflower, Senecio lautus. We observed strong genetic structure as well as phylogenetic clustering by geography and show that this is unlikely due to gene flow between parapatric ecotypes, which was surprisingly low. We further confirm this analytically by demonstrating that phylogenetic distortion due to gene flow often requires higher levels of migration than those observed in S. lautus. Our results imply that selection can repeatedly create similar phenotypes despite the perceived homogenizing effects of gene flow.
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Affiliation(s)
- Maddie E James
- School of Biological Sciences, The University of Queensland,St. Lucia, QLD, Australia
| | - Henry Arenas-Castro
- School of Biological Sciences, The University of Queensland,St. Lucia, QLD, Australia
| | - Jeffrey S Groh
- School of Biological Sciences, The University of Queensland,St. Lucia, QLD, Australia
| | - Scott L Allen
- School of Biological Sciences, The University of Queensland,St. Lucia, QLD, Australia
| | - Jan Engelstädter
- School of Biological Sciences, The University of Queensland,St. Lucia, QLD, Australia
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7
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Becher H, Powell RF, Brown MR, Metherell C, Pellicer J, Leitch IJ, Twyford AD. The nature of intraspecific and interspecific genome size variation in taxonomically complex eyebrights. ANNALS OF BOTANY 2021; 128:639-651. [PMID: 34318876 PMCID: PMC8422891 DOI: 10.1093/aob/mcab102] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 07/27/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND AND AIMS Genome size varies considerably across the diversity of plant life. Although genome size is, by definition, affected by genetic presence/absence variants, which are ubiquitous in population sequencing studies, genome size is often treated as an intrinsic property of a species. Here, we studied intra- and interspecific genome size variation in taxonomically complex British eyebrights (Euphrasia, Orobanchaceae). Our aim is to document genome size diversity and investigate underlying evolutionary processes shaping variation between individuals, populations and species. METHODS We generated genome size data for 192 individuals of diploid and tetraploid Euphrasia and analysed genome size variation in relation to ploidy, taxonomy, population affiliation and geography. We further compared the genomic repeat content of 30 samples. KEY RESULTS We found considerable intraspecific genome size variation, and observed isolation-by-distance for genome size in outcrossing diploids. Tetraploid Euphrasia showed contrasting patterns, with genome size increasing with latitude in outcrossing Euphrasia arctica, but with little genome size variation in the highly selfing Euphrasia micrantha. Interspecific differences in genome size and the genomic proportions of repeat sequences were small. CONCLUSIONS We show the utility of treating genome size as the outcome of polygenic variation. Like other types of genetic variation, such as single nucleotide polymorphisms, genome size variation may be affected by ongoing hybridization and the extent of population subdivision. In addition to selection on associated traits, genome size is predicted to be affected indirectly by selection due to pleiotropy of the underlying presence/absence variants.
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Affiliation(s)
- Hannes Becher
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | | | - Max R Brown
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
- Wellcome Trust Genome Campus, Hinxton, Saffron Walden, UK
| | - Chris Metherell
- Botanical Society of Britain and Ireland, Harpenden, Hertfordshire, UK
| | - Jaume Pellicer
- Royal Botanic Gardens, Kew, Richmond, Surrey, UK
- Institut Botànic de Barcelona (IBB, CSIC-Ajuntament de Barcelona), Barcelona, Spain
| | | | - Alex D Twyford
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
- Royal Botanic Garden Edinburgh, Edinburgh, UK
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8
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Hirota SK, Yasumoto AA, Nitta K, Tagane M, Miki N, Suyama Y, Yahara T. Evolutionary history of Hemerocallis in Japan inferred from chloroplast and nuclear phylogenies and levels of interspecific gene flow. Mol Phylogenet Evol 2021; 164:107264. [PMID: 34273506 DOI: 10.1016/j.ympev.2021.107264] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 06/22/2021] [Accepted: 07/12/2021] [Indexed: 10/20/2022]
Abstract
The perennial herb genus Hemerocallis (Asphodelaceae) shows four flowering types: diurnal half-day, diurnal one-day, nocturnal half-day, and nocturnal one-day flowering. These flowering types are corresponding to their main pollinators, and probably act as a primary mechanism of reproductive isolation. To examine how the four flowering types diverged, we reconstructed the phylogeny of the Japanese species of Hemerocallis using 1615 loci of nuclear genome-wide SNPs and 2078 bp sequences of four cpDNA regions. We also examined interspecific gene flows among taxa by an Isolation-with-Migration model and a population structure analysis. Our study revealed an inconsistency between chloroplast and nuclear genome phylogenies, which may have resulted from chloroplast capture. Each of the following five clusters is monophyletic and clearly separated on the nuclear genome-wide phylogenetic tree: (I) two nocturnal flowering species with lemon-yellow flowers, H. citrina (half-day flowering) and H. lilioasphodelus (one-day flowering); (II) a diurnal one-day flowering species with yellow-orange flowers, H. middendorffii; (III) a variety of a diurnal half-day flowering species with reddish orange flowers, H. fulva var. disticha; (IV) another variety of a diurnal half-day flowering species with reddish orange flowers, H. fulva var. aurantiaca, and a diurnal one-day flowering species with yellow-orange flowers, H. major; (V) a diurnal half-day flowering species with yellow-orange flowers, H. hakuunensis. The five clusters are consistent with traditional phenotype-based taxonomy (cluster I, cluster II, and clusters III-V correspond to Hemerocallis sect. Hemerocallis, Capitatae, and Fulvae, respectively). These findings could indicate that three flowering types (nocturnal flowering, diurnal one-day flowering, and diurnal half-day flowering) diverged in early evolutionary stages of Hemerocallis and subsequently a change from diurnal half-day flowering to diurnal one-day flowering occurred in a lineage of H. major. While genetic differentiation among the five clusters was well maintained, significant gene flow was detected between most pairs of taxa, suggesting that repeated hybridization played a role in the evolution of those taxa.
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Affiliation(s)
- Shun K Hirota
- Field Science Center, Graduate School of Agricultural Science, Tohoku University, 232-3 Aza-yomogida, Naruko Onsen, Osaki, Miyagi 989-6711, Japan.
| | - Akiko A Yasumoto
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Kozue Nitta
- Department of Environmental Science, School of Life and Environmental Science, Azabu University, 1-17-71 Fuchinobe, Chuo, Sagamihara, Kanagawa 252-5201, Japan
| | - Misa Tagane
- Department of Biology, Faculty of Science, Kyushu University, 744 Motooka, Fukuoka 819-0395, Japan
| | - Nozomu Miki
- Graduate School of Systems Life Sciences, Kyushu University, 744 Motooka, Fukuoka 819-0395, Japan
| | - Yoshihisa Suyama
- Field Science Center, Graduate School of Agricultural Science, Tohoku University, 232-3 Aza-yomogida, Naruko Onsen, Osaki, Miyagi 989-6711, Japan
| | - Tetsukazu Yahara
- Department of Biology, Faculty of Science, Kyushu University, 744 Motooka, Fukuoka 819-0395, Japan
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9
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Owens GL, Todesco M, Bercovich N, Légaré JS, Mitchell N, Whitney KD, Rieseberg LH. Standing variation rather than recent adaptive introgression probably underlies differentiation of the texanus subspecies of Helianthus annuus. Mol Ecol 2021; 30:6229-6245. [PMID: 34080243 DOI: 10.1111/mec.16008] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 05/17/2021] [Accepted: 05/26/2021] [Indexed: 12/24/2022]
Abstract
The origins of geographic races in wide-ranging species are poorly understood. In Texas, the texanus subspecies of Helianthus annuus has long been thought to have acquired its defining phenotypic traits via introgression from a local congener, H. debilis, but previous tests of this hypothesis were inconclusive. Here, we explore the origins of H. a. texanus using whole genome sequencing data from across the entire range of H. annuus and possible donor species, as well as phenotypic data from a common garden study. We found that although it is morphologically convergent with H. debilis, H. a. texanus has conflicting signals of introgression. Genome wide tests (Patterson's D and TreeMix) only found evidence of introgression from H. argophyllus (sister species to H. annuus and also sympatric), but not H. debilis, with the exception of one individual of 109 analysed. We further scanned the genome for localized signals of introgression using PCAdmix and found minimal but nonzero introgression from H. debilis and significant introgression from H. argophyllus in some populations. Given the paucity of introgression from H. debilis, we argue that the morphological convergence observed in Texas is probably from standing genetic variation. We also found that genomic differentiation in H. a. texanus is mostly driven by large segregating inversions, several of which have signatures of natural selection based on haplotype frequencies.
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Affiliation(s)
- Gregory L Owens
- Department of Biology, University of Victoria, Victoria, BC, Canada
| | - Marco Todesco
- Department of Botany and Biodiversity Research Centre, University of British Columbia, Vancouver, BC, Canada
| | - Natalia Bercovich
- Department of Botany and Biodiversity Research Centre, University of British Columbia, Vancouver, BC, Canada
| | - Jean-Sébastien Légaré
- Department of Botany and Biodiversity Research Centre, University of British Columbia, Vancouver, BC, Canada
| | - Nora Mitchell
- Department of Biology, University of Wisconsin - Eau Claire, Eau Claire, WI, USA.,Department of Biology, University of New Mexico, Albuquerque, NM, USA
| | - Kenneth D Whitney
- Department of Biology, University of New Mexico, Albuquerque, NM, USA
| | - Loren H Rieseberg
- Department of Botany and Biodiversity Research Centre, University of British Columbia, Vancouver, BC, Canada
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10
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Liu Y, Wang B, Shu S, Li Z, Song C, Liu D, Niu Y, Liu J, Zhang J, Liu H, Hu Z, Huang B, Liu X, Liu W, Jiang L, Alami MM, Zhou Y, Ma Y, He X, Yang Y, Zhang T, Hu H, Barker MS, Chen S, Wang X, Nie J. Analysis of the Coptis chinensis genome reveals the diversification of protoberberine-type alkaloids. Nat Commun 2021; 12:3276. [PMID: 34078898 PMCID: PMC8172641 DOI: 10.1038/s41467-021-23611-0] [Citation(s) in RCA: 57] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Accepted: 05/07/2021] [Indexed: 02/04/2023] Open
Abstract
Chinese goldthread (Coptis chinensis Franch.), a member of the Ranunculales, represents an important early-diverging eudicot lineage with diverse medicinal applications. Here, we present a high-quality chromosome-scale genome assembly and annotation of C. chinensis. Phylogenetic and comparative genomic analyses reveal the phylogenetic placement of this species and identify a single round of ancient whole-genome duplication (WGD) shared by the Ranunculaceae. We characterize genes involved in the biosynthesis of protoberberine-type alkaloids in C. chinensis. In particular, local genomic tandem duplications contribute to member amplification of a Ranunculales clade-specific gene family of the cytochrome P450 (CYP) 719. The functional versatility of a key CYP719 gene that encodes the (S)-canadine synthase enzyme involved in the berberine biosynthesis pathway may play critical roles in the diversification of other berberine-related alkaloids in C. chinensis. Our study provides insights into the genomic landscape of early-diverging eudicots and provides a valuable model genome for genetic and applied studies of Ranunculales.
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Affiliation(s)
- Yifei Liu
- College of Pharmacy, Hubei University of Chinese Medicine, Wuhan, China.
| | - Bo Wang
- Hubei Institute for Drug Control, Wuhan, China
| | - Shaohua Shu
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Zheng Li
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, USA
| | - Chi Song
- Wuhan Benagen Tech Solutions Company Limited, Wuhan, China
| | - Di Liu
- College of Pharmacy, Hubei University of Chinese Medicine, Wuhan, China
| | - Yan Niu
- Wuhan Benagen Tech Solutions Company Limited, Wuhan, China
| | - Jinxin Liu
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Jingjing Zhang
- College of Pharmacy, Hubei University of Chinese Medicine, Wuhan, China
| | - Heping Liu
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Zhigang Hu
- College of Pharmacy, Hubei University of Chinese Medicine, Wuhan, China
| | - Bisheng Huang
- College of Pharmacy, Hubei University of Chinese Medicine, Wuhan, China
| | - Xiuyu Liu
- National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, China
| | - Wei Liu
- College of Pharmacy, Hubei University of Chinese Medicine, Wuhan, China
| | - Liping Jiang
- College of Pharmacy, Hubei University of Chinese Medicine, Wuhan, China
| | | | - Yuxin Zhou
- Hubei Institute for Drug Control, Wuhan, China
| | - Yutao Ma
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Xiangxiang He
- Wuhan Benagen Tech Solutions Company Limited, Wuhan, China
| | - Yicheng Yang
- Wuhan Benagen Tech Solutions Company Limited, Wuhan, China
| | - Tianyuan Zhang
- Wuhan Benagen Tech Solutions Company Limited, Wuhan, China
| | - Hui Hu
- Jing Brand Chizhengtang Pharmaceutical Company Limited, Huangshi, China
| | - Michael S Barker
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, USA
| | - Shilin Chen
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, China.
| | - Xuekui Wang
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China.
| | - Jing Nie
- Hubei Institute for Drug Control, Wuhan, China.
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11
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Azarin K, Usatov A, Makarenko M, Khachumov V, Gavrilova V. Comparative analysis of chloroplast genomes of seven perennial Helianthus species. Gene 2021; 774:145418. [PMID: 33444687 DOI: 10.1016/j.gene.2021.145418] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 12/15/2020] [Accepted: 01/05/2021] [Indexed: 10/25/2022]
Abstract
Sequencing and a comparative analysis of the complete chloroplast genomes of seven perennial Helianthus species were carried out. The chloroplast genomes have a typical quadripartite structure, including large and small single regions and a pair of inverted repeats. Genome sizes were between 151,152 bp and 151,289 bp. The genome of H. grosseserratus was the smallest, while that of H. microcephalus was the largest. The size variation of the chloroplast genomes is substantially due to the change in the length of simple sequence repeats (SSRs) in non-coding regions. An analysis of these SSRs revealed 35 polymorphic loci (average PIC value > 0.5) that can be used to examine ecological and evolutionary processes in wild Helianthus species. Eight divergence hotspots, including five intergenic regions (petN-psbM, clpP intron, rps3-rpl16, ndhD-ccsA, and ndhF-rpl32) and three gene regions (rbcL, ycf1, and ndhF) were also identified in Helianthus chloroplast genomes. The evolutionary selection pressure analysis revealed a strong purifying selection. Only the rbcL gene experienced efficiency of positive selection at the annual/perennial transitions. The inverted repeat (IR)/single copy (SC) boundaries were identical in all of these (Helianthus) species. In general, the comparison of the genomes revealed low levels of sequence variability (Pi = 0.00051). This indicates that the chloroplast genomes of the studied perennial species of Helianthus, in addition to purifying selection, are closely related and have a recent divergence time.
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Affiliation(s)
- Kirill Azarin
- Southern Federal University, Rostov-on-Don, Russian Federation; Agricultural Research Center "Donskoy", Zernograd, Russian Federation.
| | | | - Maksim Makarenko
- Institute for Information Transmission Problems, Moscow, Russian Federation
| | | | - Vera Gavrilova
- Vavilov All Russian Institute of Plant Genetic Resources, Saint Petersburg, Russian Federation
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12
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Confer JL, Porter C, Aldinger KR, Canterbury RA, Larkin JL, Mcneil DJ. Implications for evolutionary trends from the pairing frequencies among golden-winged and blue-winged warblers and their hybrids. Ecol Evol 2020; 10:10633-10644. [PMID: 33072285 PMCID: PMC7548172 DOI: 10.1002/ece3.6717] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 07/28/2020] [Accepted: 08/03/2020] [Indexed: 01/29/2023] Open
Abstract
Extensive range loss for the Golden-winged Warbler (Vermivora chrysoptera) has occurred in areas of intrusion by the Blue-winged Warbler (V. cyanoptera) potentially related to their close genetic relationship. We compiled data on social pairing from nine studies for 2,679 resident Vermivora to assess evolutionary divergence. Hybridization between pure phenotypes occurred with 1.2% of resident males for sympatric populations. Pairing success rates for Golden-winged Warblers was 83% and for Blue-winged Warblers was 77%. Pairing success for the hybrid Brewster's Warbler was significantly lower from both species at 54%, showing sexual selection against hybrids. Backcross frequencies for Golden-winged Warblers at 4.9% were significantly higher than for Blue-winged Warblers at 1.7%. More frequent backcrossing by Golden-winged Warblers, which produces hybrid phenotypes, may contribute to the replacement of Golden-winged by Blue-winged Warblers. Reproductive isolation due to behavioral isolation plus sexual selection against hybrids was 0.960. Our analyses suggest that plumage differences are the main driving force for this strong isolation with reduced hybrid fitness contributing to a lesser degree. The major impact of plumage differences to reproductive isolation is compatible with genomic analyses (Current Biology, 2016, 26, 2313), which showed the largest genetic difference between these phenotypes occurred with plumage genes. These phenotypes have maintained morphological, behavioral, and ecological differences during two centuries of hybridization. Our estimate of reproductive isolation supports recognition of these phenotypes as two species. The decline and extirpation of the Golden-winged Warbler in almost all areas of recent sympatry suggest that continued coexistence of both species will require eco-geographic isolation.
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Affiliation(s)
| | - Cody Porter
- Department of Zoology and PhysiologyUniversity of WyomingLaramieWYUSA
- Wildlife Biology ProgramLees‐McRae CollegeBanner ElkNCUSA
| | - Kyle R. Aldinger
- West Virginia Cooperative Fish and Wildlife Research Unit, Division of Forestry and Natural Resources, West Virginia UniversityMorgantownWVUSA
| | | | | | - Darin J. Mcneil
- Department of EntomologyThe Pennsylvania State UniversityUniversity ParkPAUSA
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13
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Wu CI, Wang X, He Z, Shi S. Replies to the commentaries on the question of 'Is it time to abandon the biological species concept?'. Natl Sci Rev 2020; 7:1407-1409. [PMID: 34692170 PMCID: PMC8289014 DOI: 10.1093/nsr/nwaa117] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Affiliation(s)
- Chung-I Wu
- State Key Laboratory of Biocontrol, Guangdong Key Lab of Plant Resources, School of Life Sciences, Sun Yat-Sen University, China
| | - Xinfeng Wang
- State Key Laboratory of Biocontrol, Guangdong Key Lab of Plant Resources, School of Life Sciences, Sun Yat-Sen University, China
| | - Ziwen He
- State Key Laboratory of Biocontrol, Guangdong Key Lab of Plant Resources, School of Life Sciences, Sun Yat-Sen University, China
| | - Suhua Shi
- State Key Laboratory of Biocontrol, Guangdong Key Lab of Plant Resources, School of Life Sciences, Sun Yat-Sen University, China
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14
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Massive haplotypes underlie ecotypic differentiation in sunflowers. Nature 2020; 584:602-607. [PMID: 32641831 DOI: 10.1038/s41586-020-2467-6] [Citation(s) in RCA: 177] [Impact Index Per Article: 44.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2019] [Accepted: 04/16/2020] [Indexed: 12/22/2022]
Abstract
Species often include multiple ecotypes that are adapted to different environments1. However, it is unclear how ecotypes arise and how their distinctive combinations of adaptive alleles are maintained despite hybridization with non-adapted populations2-4. Here, by resequencing 1,506 wild sunflowers from 3 species (Helianthus annuus, Helianthus petiolaris and Helianthus argophyllus), we identify 37 large (1-100 Mbp in size), non-recombining haplotype blocks that are associated with numerous ecologically relevant traits, as well as soil and climate characteristics. Limited recombination in these haplotype blocks keeps adaptive alleles together, and these regions differentiate sunflower ecotypes. For example, haplotype blocks control a 77-day difference in flowering between ecotypes of the silverleaf sunflower H. argophyllus (probably through deletion of a homologue of FLOWERING LOCUS T (FT)), and are associated with seed size, flowering time and soil fertility in dune-adapted sunflowers. These haplotypes are highly divergent, frequently associated with structural variants and often appear to represent introgressions from other-possibly now-extinct-congeners. These results highlight a pervasive role of structural variation in ecotypic adaptation.
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15
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Ostevik KL, Samuk K, Rieseberg LH. Ancestral Reconstruction of Karyotypes Reveals an Exceptional Rate of Nonrandom Chromosomal Evolution in Sunflower. Genetics 2020; 214:1031-1045. [PMID: 32033968 PMCID: PMC7153943 DOI: 10.1534/genetics.120.303026] [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] [Received: 08/15/2019] [Accepted: 02/03/2020] [Indexed: 12/20/2022] Open
Abstract
Mapping the chromosomal rearrangements between species can inform our understanding of genome evolution, reproductive isolation, and speciation. Here, we present a novel algorithm for identifying regions of synteny in pairs of genetic maps, which is implemented in the accompanying R package syntR. The syntR algorithm performs as well as previous ad hoc methods while being systematic, repeatable, and applicable to mapping chromosomal rearrangements in any group of species. In addition, we present a systematic survey of chromosomal rearrangements in the annual sunflowers, which is a group known for extreme karyotypic diversity. We build high-density genetic maps for two subspecies of the prairie sunflower, Helianthus petiolaris ssp. petiolaris and H. petiolaris ssp. fallax Using syntR, we identify blocks of synteny between these two subspecies and previously published high-density genetic maps. We reconstruct ancestral karyotypes for annual sunflowers using those synteny blocks and conservatively estimate that there have been 7.9 chromosomal rearrangements per million years, a high rate of chromosomal evolution. Although the rate of inversion is even higher than the rate of translocation in this group, we further find that every extant karyotype is distinguished by between one and three translocations involving only 8 of the 17 chromosomes. This nonrandom exchange suggests that specific chromosomes are prone to translocation and may thus contribute disproportionately to widespread hybrid sterility in sunflowers. These data deepen our understanding of chromosome evolution and confirm that Helianthus has an exceptional rate of chromosomal rearrangement that may facilitate similarly rapid diversification.
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Affiliation(s)
- Kate L Ostevik
- Department of Biology, Duke University, Durham, North Carolina 27701
- Department of Botany, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Kieran Samuk
- Department of Biology, Duke University, Durham, North Carolina 27701
| | - Loren H Rieseberg
- Department of Botany, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
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16
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Porter CK, Benkman CW. Character displacement of a learned behaviour and its implications for ecological speciation. Proc Biol Sci 2019; 286:20190761. [PMID: 31362636 DOI: 10.1098/rspb.2019.0761] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Cultural evolution may accelerate population divergence and speciation, though most support for this hypothesis is restricted to scenarios of allopatric speciation driven by random cultural drift. By contrast, the role of cultural evolution in non-allopatric speciation (i.e. speciation with gene flow) has received much less attention. One clade in which cultural evolution may have figured prominently in speciation with gene flow includes the conifer-seed-eating finches in the red crossbill (Loxia curvirostra) complex. Here we focus on Cassia crossbills (Loxia sinesciuris; an ecotype recently split taxonomically from red crossbills) that learn social contact calls from their parents. Previous work found that individuals modify their calls throughout life such that they become increasingly divergent from a closely related, sympatric red crossbill ecotype. This open-ended modification of calls could lead to character displacement if it causes population-level divergence in call structure that, in turn, reduces (maladaptive) heterospecific flocking. Heterospecific flocking is maladaptive because crossbills use public information from flockmates to assess resource quality, and feeding rates are depressed when flockmates differ in their ability to exploit a shared resource (i.e. when flockmates are heterospecifics). We confirm the predictions of character displacement by documenting substantial population-level divergence in Cassia crossbill call structure over just two decades and by using field experiments to demonstrate that Cassia and red crossbills differentially respond to these evolved differences in call structure, reducing heterospecific flock formation. Moreover, because crossbills choose mates from within flocks, a reduction in heterospecific flocking should increase assortative mating and may have been critical for speciation of Cassia crossbills in the face of ongoing gene flow in as few as 5000 years. Our results provide evidence for a largely neglected yet potentially widespread mechanism by which reproductive isolation can evolve between sympatric lineages as a byproduct of adaptive cultural evolution.
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Affiliation(s)
- Cody K Porter
- Program in Ecology, Department of Zoology and Physiology, University of Wyoming, 1000 East University Avenue, Laramie, WY 82071, USA
| | - Craig W Benkman
- Program in Ecology, Department of Zoology and Physiology, University of Wyoming, 1000 East University Avenue, Laramie, WY 82071, USA
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17
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Karrenberg S, Liu X, Hallander E, Favre A, Herforth-Rahmé J, Widmer A. Ecological divergence plays an important role in strong but complex reproductive isolation in campions (Silene). Evolution 2018; 73:245-261. [PMID: 30499144 DOI: 10.1111/evo.13652] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 11/13/2018] [Accepted: 01/16/2018] [Indexed: 12/27/2022]
Abstract
New species arise through the evolution of reproductive barriers between formerly interbreeding lineages. Yet, comprehensive assessments of potential reproductive barriers, which are needed to make inferences on processes driving speciation, are only available for a limited number of systems. In this study, we estimated individual and cumulative strengths of seven prezygotic and six postzygotic reproductive barriers between the recently diverged taxa Silene dioica (L.) Clairv. and S. latifolia Poiret using both published and new data. A combination of multiple partial reproductive barriers resulted in near-complete reproductive isolation between S. dioica and S. latifolia, consistent with earlier estimates of gene flow between the taxa. Extrinsic barriers associated with adaptive ecological divergence were most important, while intrinsic postzygotic barriers had moderate individual strength but contributed only little to total reproductive isolation. These findings are in line with ecological divergence as driver of speciation. We further found extensive variation in extrinsic reproductive isolation, ranging from sites with very strong selection against migrants and hybrids to intermediate sites where substantial hybridization is possible. This situation may allow for, or even promote, heterogeneous genetic divergence.
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Affiliation(s)
- Sophie Karrenberg
- Department of Ecology and Genetics, Uppsala University, Norbyvägen 18 D, 75236, Uppsala, Sweden
| | - Xiaodong Liu
- Department of Ecology and Genetics, Uppsala University, Norbyvägen 18 D, 75236, Uppsala, Sweden
| | - Emelie Hallander
- Department of Ecology and Genetics, Uppsala University, Norbyvägen 18 D, 75236, Uppsala, Sweden.,Current Address: Swedish Board of Agriculture, Vallgatan 8, 551 82, Jönköping, Sweden
| | - Adrien Favre
- Department of Diversity and Evolution of Higher Plants, Institute of Ecology, Evolution and Diversity, Goethe-University, 60439, Frankfurt am Main, Germany.,Senckenberg Research Institute and Natural History Museum, Senckenberganlage 25, 60325, Frankfurt am Main, Germany
| | - Joelle Herforth-Rahmé
- ETH Zurich, Institute of Integrative Biology, Universitätstrasse 16, 8092, Zürich, Switzerland.,Current Address: Research Institute of Organic Agriculture FiBL, Department of Soil Sciences, Ackerstrasse 113, Box 219, 5070, Frick, Switzerland
| | - Alex Widmer
- ETH Zurich, Institute of Integrative Biology, Universitätstrasse 16, 8092, Zürich, Switzerland
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18
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Song C, Liu Y, Song A, Dong G, Zhao H, Sun W, Ramakrishnan S, Wang Y, Wang S, Li T, Niu Y, Jiang J, Dong B, Xia Y, Chen S, Hu Z, Chen F, Chen S. The Chrysanthemum nankingense Genome Provides Insights into the Evolution and Diversification of Chrysanthemum Flowers and Medicinal Traits. MOLECULAR PLANT 2018; 11:1482-1491. [PMID: 30342096 DOI: 10.1016/j.molp.2018.10.003] [Citation(s) in RCA: 111] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 09/25/2018] [Accepted: 10/10/2018] [Indexed: 05/21/2023]
Abstract
The Asteraceae (Compositae), a large plant family of approximately 24 000-35 000 species, accounts for ∼10% of all angiosperm species and contributes a lot to plant diversity. The most representative members of the Asteraceae are the economically important chrysanthemums (Chrysanthemum L.) that diversified through reticulate evolution. Biodiversity is typically created by multiple evolutionary mechanisms such as whole-genome duplication (WGD) or polyploidization and locally repetitive genome expansion. However, the lack of genomic data from chrysanthemum species has prevented an in-depth analysis of the evolutionary mechanisms involved in their diversification. Here, we used Oxford Nanopore long-read technology to sequence the diploid Chrysanthemum nankingense genome, which represents one of the progenitor genomes of domesticated chrysanthemums. Our analysis revealed that the evolution of the C. nankingense genome was driven by bursts of repetitive element expansion and WGD events including a recent WGD that distinguishes chrysanthemum from sunflower, which diverged from chrysanthemum approximately 38.8 million years ago. Variations of ornamental and medicinal traits in chrysanthemums are linked to the expansion of candidate gene families by duplication events including paralogous gene duplication. Collectively, our study of the assembled reference genome offers new knowledge and resources to dissect the history and pattern of evolution and diversification of chrysanthemum plants, and also to accelerate their breeding and improvement.
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Affiliation(s)
- Chi Song
- Key Laboratory of Beijing for Identification and Safety Evaluation of Chinese Medicine, Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Yifei Liu
- College of Pharmacy, Hubei University of Chinese Medicine, Wuhan 430065, China
| | - Aiping Song
- College of Horticulture, Nanjing Agricultural University, Key Laboratory of Landscape Agriculture, Ministry of Agriculture, Nanjing 210095, China
| | | | - Hongbo Zhao
- Department of Ornamental Horticulture, School of Landscape Architecture, Zhejiang Agriculture and Forestry University, Hangzhou 311300, China
| | - Wei Sun
- Key Laboratory of Beijing for Identification and Safety Evaluation of Chinese Medicine, Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China
| | | | - Ying Wang
- Wuhan Benagen Tech Solutions Company Limited, Wuhan 430070, China
| | - Shuaibin Wang
- Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, The Chinese Academy of Sciences, Guangzhou 510650, China
| | - Tingzhao Li
- Amway (China) Botanical R&D Center, Wuxi 214115, China
| | - Yan Niu
- Wuhan Benagen Tech Solutions Company Limited, Wuhan 430070, China
| | - Jiafu Jiang
- College of Horticulture, Nanjing Agricultural University, Key Laboratory of Landscape Agriculture, Ministry of Agriculture, Nanjing 210095, China
| | - Bin Dong
- Department of Ornamental Horticulture, School of Landscape Architecture, Zhejiang Agriculture and Forestry University, Hangzhou 311300, China
| | - Ye Xia
- Wuhan Benagen Tech Solutions Company Limited, Wuhan 430070, China
| | - Sumei Chen
- College of Horticulture, Nanjing Agricultural University, Key Laboratory of Landscape Agriculture, Ministry of Agriculture, Nanjing 210095, China
| | - Zhigang Hu
- College of Pharmacy, Hubei University of Chinese Medicine, Wuhan 430065, China
| | - Fadi Chen
- College of Horticulture, Nanjing Agricultural University, Key Laboratory of Landscape Agriculture, Ministry of Agriculture, Nanjing 210095, China.
| | - Shilin Chen
- Key Laboratory of Beijing for Identification and Safety Evaluation of Chinese Medicine, Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China.
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19
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Sousa F, Bertrand YJK, Doyle JJ, Oxelman B, Pfeil BE. Using Genomic Location and Coalescent Simulation to Investigate Gene Tree Discordance in Medicago L. Syst Biol 2018; 66:934-949. [PMID: 28177088 DOI: 10.1093/sysbio/syx035] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 02/01/2017] [Indexed: 12/28/2022] Open
Abstract
Several well-documented evolutionary processes are known to cause conflict between species-level phylogenies and gene-level phylogenies. Three of the most challenging processes for species tree inference are incomplete lineage sorting, hybridization and gene duplication, which may result in unwarranted comparisons of paralogous genes. Several existing methods have dealt with these processes but none has yet been able to untangle all three at once. Here, we propose a stepwise method by which these processes can be discerned using information on genomic location coupled with coalescent simulations. In the first step, highly discordant genes within genomic blocks (putative paralogs) are identified and excluded from the data set and, in the second step, blocks of linked genes are grouped according to their hybrid history. Existing multispecies coalescent software can then be applied to recover the principal tree(s) that make up the species tree/network without violating the underlying model. The potential of the approach is evaluated on simulated data derived from a species network composed of nine species, of which one is of hybrid origin, and displaying a single-gene duplication that leads to paralogous comparisons. We apply our method to an empirical set of 12 genes from 7 species sampled in the plant genus Medicago that display phylogenetic discordance. We identify the causes of the discordance and demonstrate that the Medicago orbicularis lineage experienced an episode of ancient hybridization. Our results show promise as a new way to explore phylogenetic sequence data that can significantly improve species tree inference in presence of hybridization and undetected paralogy or other causes leading to extremely discordant gene trees. [Coalescent simulation; gene tree; genomic location; hybridization; incomplete lineage sorting; paralogy; phylogenetic incongruence; principal tree; species tree.].
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Affiliation(s)
- F Sousa
- Department of Biological and Environmental Sciences, University of Gothenburg, Box 461, 40530 Gothenburg, Sweden
| | - Y J K Bertrand
- Department of Biological and Environmental Sciences, University of Gothenburg, Box 461, 40530 Gothenburg, Sweden
| | - J J Doyle
- Department of Plant Biology, Cornell University, 404 Mann Library Building, Ithaca, NY 14853, USA
| | - B Oxelman
- Department of Biological and Environmental Sciences, University of Gothenburg, Box 461, 40530 Gothenburg, Sweden
| | - B E Pfeil
- Department of Biological and Environmental Sciences, University of Gothenburg, Box 461, 40530 Gothenburg, Sweden
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20
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Reeve J, Ortiz-Barrientos D, Engelstädter J. The evolution of recombination rates in finite populations during ecological speciation. Proc Biol Sci 2017; 283:rspb.2016.1243. [PMID: 27798297 DOI: 10.1098/rspb.2016.1243] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2016] [Accepted: 10/04/2016] [Indexed: 11/12/2022] Open
Abstract
Recombination can impede ecological speciation with gene flow by mixing locally adapted genotypes with maladapted migrant genotypes from a divergent population. In such a scenario, suppression of recombination can be selectively favoured. However, in finite populations evolving under the influence of random genetic drift, recombination can also facilitate adaptation by reducing Hill-Robertson interference between loci under selection. In this case, increased recombination rates can be favoured. Although these two major effects on recombination have been studied individually, their joint effect on ecological speciation with gene flow remains unexplored. Using a mathematical model, we investigated the evolution of recombination rates in two finite populations that exchange migrants while adapting to contrasting environments. Our results indicate a two-step dynamic where increased recombination is first favoured (in response to the Hill-Robertson effect), and then disfavoured, as the cost of recombining locally with maladapted migrant genotypes increases over time (the maladaptive gene flow effect). In larger populations, a stronger initial benefit for recombination was observed, whereas high migration rates intensify the long-term cost of recombination. These dynamics may have important implications for our understanding of the conditions that facilitate incipient speciation with gene flow and the evolution of recombination in finite populations.
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Affiliation(s)
- James Reeve
- School of Biological Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Daniel Ortiz-Barrientos
- School of Biological Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Jan Engelstädter
- School of Biological Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia
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21
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The sunflower genome provides insights into oil metabolism, flowering and Asterid evolution. Nature 2017; 546:148-152. [PMID: 28538728 DOI: 10.1038/nature22380] [Citation(s) in RCA: 407] [Impact Index Per Article: 58.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 04/16/2017] [Indexed: 12/30/2022]
Abstract
The domesticated sunflower, Helianthus annuus L., is a global oil crop that has promise for climate change adaptation, because it can maintain stable yields across a wide variety of environmental conditions, including drought. Even greater resilience is achievable through the mining of resistance alleles from compatible wild sunflower relatives, including numerous extremophile species. Here we report a high-quality reference for the sunflower genome (3.6 gigabases), together with extensive transcriptomic data from vegetative and floral organs. The genome mostly consists of highly similar, related sequences and required single-molecule real-time sequencing technologies for successful assembly. Genome analyses enabled the reconstruction of the evolutionary history of the Asterids, further establishing the existence of a whole-genome triplication at the base of the Asterids II clade and a sunflower-specific whole-genome duplication around 29 million years ago. An integrative approach combining quantitative genetics, expression and diversity data permitted development of comprehensive gene networks for two major breeding traits, flowering time and oil metabolism, and revealed new candidate genes in these networks. We found that the genomic architecture of flowering time has been shaped by the most recent whole-genome duplication, which suggests that ancient paralogues can remain in the same regulatory networks for dozens of millions of years. This genome represents a cornerstone for future research programs aiming to exploit genetic diversity to improve biotic and abiotic stress resistance and oil production, while also considering agricultural constraints and human nutritional needs.
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22
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Martin H, Touzet P, Dufay M, Godé C, Schmitt E, Lahiani E, Delph LF, Van Rossum F. Lineages of Silene nutans developed rapid, strong, asymmetric postzygotic reproductive isolation in allopatry. Evolution 2017; 71:1519-1531. [PMID: 28384386 DOI: 10.1111/evo.13245] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Revised: 03/18/2017] [Accepted: 03/23/2017] [Indexed: 12/15/2022]
Abstract
Reproductive isolation can rise either as a consequence of genomic divergence in allopatry or as a byproduct of divergent selection in parapatry. To determine whether reproductive isolation in gynodioecious Silene nutans results from allopatric divergence or from ecological adaptation following secondary contact, we investigated the pattern of postzygotic reproductive isolation and hybridization in natural populations using two phylogeographic lineages, western (W1) and eastern (E1). Experimental crosses between the lineages identified strong, asymmetric postzygotic isolation between the W1 and the E1 lineages, independent of geographic overlap. The proportion of ovules fertilized, seeds aborted, and seeds germinated revealed relatively little effect on the fitness of hybrids. In contrast, hybrid mortality was high and asymmetric: while half of the hybrid seedlings with western lineage mothers died, nearly all hybrid seedlings with E1 mothers died. This asymmetric mortality mirrored the proportion of chlorotic seedlings, and is congruent with cytonuclear incompatibility. We found no evidence of hybridization between the lineages in regions of co-occurrence using nuclear and plastid markers. Together, our results are consistent with the hypothesis that strong postzygotic reproductive isolation involving cytonuclear incompatibilities arose in allopatry. We argue that the dynamics of cytonuclear gynodioecy could facilitate the evolution of reproductive isolation.
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Affiliation(s)
- Hélène Martin
- Unité Évolution, Écologie, Paléontologie, UMR CNRS 8198, Université de Lille 1-Sciences et Technologies, F-59655, Villeneuve d'Ascq, France
| | - Pascal Touzet
- Unité Évolution, Écologie, Paléontologie, UMR CNRS 8198, Université de Lille 1-Sciences et Technologies, F-59655, Villeneuve d'Ascq, France
| | - Mathilde Dufay
- Unité Évolution, Écologie, Paléontologie, UMR CNRS 8198, Université de Lille 1-Sciences et Technologies, F-59655, Villeneuve d'Ascq, France
| | - Cécile Godé
- Unité Évolution, Écologie, Paléontologie, UMR CNRS 8198, Université de Lille 1-Sciences et Technologies, F-59655, Villeneuve d'Ascq, France
| | - Eric Schmitt
- Unité Évolution, Écologie, Paléontologie, UMR CNRS 8198, Université de Lille 1-Sciences et Technologies, F-59655, Villeneuve d'Ascq, France
| | - Emna Lahiani
- Unité Évolution, Écologie, Paléontologie, UMR CNRS 8198, Université de Lille 1-Sciences et Technologies, F-59655, Villeneuve d'Ascq, France
| | - Lynda F Delph
- Department of Biology, Indiana University, Bloomington, Indiana, 47405
| | - Fabienne Van Rossum
- Meise Botanic Garden (formerly National Botanic Garden of Belgium), Nieuwelaan 38, BE-1860, Meise, Belgium.,Écologie végétale et Biogéochimie, Université Libre de Bruxelles, CP244, Boulevard du Triomphe, BE-1050, Brussels, Belgium.,Fédération Wallonie-Bruxelles, rue A. Lavallée 1, BE-1080, Brussels, Belgium
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23
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Yang M, He Z, Huang Y, Lu L, Yan Y, Hong L, Shen H, Liu Y, Guo Q, Jiang L, Zhang Y, Greenberg AJ, Zhou R, Ge X, Wu CI, Shi S. The emergence of the hyperinvasive vine, Mikania micrantha (Asteraceae), via admixture and founder events inferred from population transcriptomics. Mol Ecol 2017; 26:3405-3423. [PMID: 28370790 DOI: 10.1111/mec.14124] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Revised: 03/20/2017] [Accepted: 03/21/2017] [Indexed: 01/14/2023]
Abstract
Biological invasions that involve well-documented rapid adaptations to new environments provide unequalled opportunities for testing evolutionary hypotheses. Mikania micrantha Kunth (Asteraceae), a perennial herbaceous vine native to tropical Central and South America, successfully invaded tropical Asia in the early 20th century. It is regarded as one of the most aggressive weeds in the world. To elucidate the molecular and evolutionary processes underlying this invasion, we extensively sampled this weed throughout its invaded range in South-East and South Asia and surveyed its genetic structure using variants detected from population transcriptomics. Clustering results suggest that more than one source population contributed to this invasion. Computer simulations using genomewide genetic variation support a scenario of admixture and founder events during invasion. The genes differentially expressed between native and invasive populations were found to be involved in oxidative and high light intensity stress responses, pointing to a possible ecological mechanism of adaptation. Our results provide a foundation for further detailed mechanistic and population studies of this ecologically and economically important invasion. This line of research promises to provide new mitigation strategies for invasive species as well as insights into mechanisms of adaptation.
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Affiliation(s)
- Ming Yang
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, Sun Yat-sen University, Guangzhou, China
| | - Ziwen He
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, Sun Yat-sen University, Guangzhou, China
| | - Yelin Huang
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, Sun Yat-sen University, Guangzhou, China
| | - Lu Lu
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, Sun Yat-sen University, Guangzhou, China
| | - Yubin Yan
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, Sun Yat-sen University, Guangzhou, China
| | - Lan Hong
- College of Horticulture and Landscape Architecture, Zhongkai University of Agriculture and Engineering, Guangzhou, Guangdong, China
| | - Hao Shen
- South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, Guangdong, China
| | - Ying Liu
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, Sun Yat-sen University, Guangzhou, China
| | - Qiang Guo
- Shenzhen Wildlife Protection Administration, Shenzhen, China
| | - Lu Jiang
- Shenzhen Wildlife Protection Administration, Shenzhen, China
| | - Yanwu Zhang
- Shenzhen Wildlife Protection Administration, Shenzhen, China
| | | | - Renchao Zhou
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, Sun Yat-sen University, Guangzhou, China
| | - Xuejun Ge
- South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, Guangdong, China
| | - Chung-I Wu
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, Sun Yat-sen University, Guangzhou, China.,Department of Ecology and Evolution, University of Chicago, Chicago, IL, USA
| | - Suhua Shi
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, Sun Yat-sen University, Guangzhou, China
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24
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Kanapeckas KL, Vigueira CC, Ortiz A, Gettler KA, Burgos NR, Fischer AJ, Lawton-Rauh AL. Escape to Ferality: The Endoferal Origin of Weedy Rice from Crop Rice through De-Domestication. PLoS One 2016; 11:e0162676. [PMID: 27661982 PMCID: PMC5035073 DOI: 10.1371/journal.pone.0162676] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Accepted: 08/26/2016] [Indexed: 11/30/2022] Open
Abstract
Domestication is the hallmark of evolution and civilization and harnesses biodiversity through selection for specific traits. In regions where domesticated lines are grown near wild relatives, congeneric sources of aggressive weedy genotypes cause major economic losses. Thus, the origins of weedy genotypes where no congeneric species occur raise questions regarding management effectiveness and evolutionary mechanisms responsible for weedy population success. Since eradication in the 1970s, California growers avoided weedy rice through continuous flood culture and zero-tolerance guidelines, preventing the import, presence, and movement of weedy seeds. In 2003, after decades of no reported presence in California, a weedy rice population was confirmed in dry-seeded fields. Our objectives were to identify the origins and establishment of this population and pinpoint possible phenotypes involved. We show that California weedy rice is derived from a different genetic source among a broad range of AA genome Oryzas and is most recently diverged from O. sativa temperate japonica cultivated in California. In contrast, other weedy rice ecotypes in North America (Southern US) originate from weedy genotypes from China near wild Oryza, and are derived through existing crop-wild relative crosses. Analyses of morphological data show that California weedy rice subgroups have phenotypes like medium-grain or gourmet cultivars, but have colored pericarp, seed shattering, and awns like wild relatives, suggesting that reversion to non-domestic or wild-like traits can occur following domestication, despite apparent fixation of domestication alleles. Additionally, these results indicate that preventive methods focused on incoming weed sources through contamination may miss burgeoning weedy genotypes that rapidly adapt, establish, and proliferate. Investigating the common and unique evolutionary mechanisms underlying global weed origins and subsequent interactions with crop relatives sheds light on how weeds evolve and addresses broader questions regarding the stability of selection during domestication and crop improvement.
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Affiliation(s)
- Kimberly L. Kanapeckas
- Department of Genetics and Biochemistry, Clemson University, Clemson, South Carolina, United States of America
- South Carolina Department of Natural Resources, Marine Resources Research Institute, Charleston, South Carolina, United States of America
| | - Cynthia C. Vigueira
- Department of Genetics and Biochemistry, Clemson University, Clemson, South Carolina, United States of America
- Department of Biology, High Point University, High Point, North Carolina, United States of America
| | - Aida Ortiz
- Department of Plant Sciences, University of California Davis, Davis, California, United States of America
| | - Kyle A. Gettler
- Department of Genetics and Biochemistry, Clemson University, Clemson, South Carolina, United States of America
| | - Nilda R. Burgos
- Department of Crop, Soil, and Environmental Sciences, University of Arkansas, Fayetteville, Arkansas, United States of America
| | - Albert J. Fischer
- Department of Plant Sciences, University of California Davis, Davis, California, United States of America
| | - Amy L. Lawton-Rauh
- Department of Genetics and Biochemistry, Clemson University, Clemson, South Carolina, United States of America
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25
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Filatov DA, Osborne OG, Papadopulos AST. Demographic history of speciation in a Senecio altitudinal hybrid zone on Mt. Etna. Mol Ecol 2016; 25:2467-81. [PMID: 26994342 DOI: 10.1111/mec.13618] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Revised: 02/29/2016] [Accepted: 02/29/2016] [Indexed: 01/16/2023]
Abstract
Hybrid zones typically form as a result of species coming into secondary contact, but can also be established in situ as an ecotonal hybrid zone, a situation which has been reported far less frequently. An altitudinal hybrid zone on Mount Etna between two ragwort species (the low elevation Senecio chrysanthemifolius and high elevation S. aethnensis) could potentially represent either of these possibilities. However, a scenario of secondary contact vs. speciation with gene flow has not been explicitly tested. Here, we test these alternatives and demonstrate that the data do not support secondary contact. Furthermore, we report that the previous analyses of speciation history of these species were based on admixed populations, which has led to inflated estimates of ongoing, interspecific gene flow. Our new analyses, based on 'pure' S. aethnensis and S. chrysanthemifolius populations, reveal gene exchange of less than one effective migrant per generation, a level low enough to allow the species to accumulate neutral, genomewide differences. Overall, our results are consistent with a scenario of speciation with gene flow and a divergence time which coincides with the rise of Mt. Etna to altitudes above 2000 m (~150 KY). Further work to quantify the role of adaptation to contrasting environments of high and low altitudes will be needed to support the scenario of recent ecological speciation in this system.
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Affiliation(s)
- Dmitry A Filatov
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, UK
| | - Owen G Osborne
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, UK
| | - Alexander S T Papadopulos
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, UK.,Royal Botanic Gardens, Kew, Richmond, TW9 3AB, UK
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26
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Osborne OG, Chapman MA, Nevado B, Filatov DA. Maintenance of Species Boundaries Despite Ongoing Gene Flow in Ragworts. Genome Biol Evol 2016; 8:1038-47. [PMID: 26979797 PMCID: PMC4860686 DOI: 10.1093/gbe/evw053] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/07/2016] [Indexed: 12/22/2022] Open
Abstract
The role of hybridization between diversifying species has been the focus of a huge amount of recent evolutionary research. While gene flow can prevent speciation or initiate species collapse, it can also generate new hybrid species. Similarly, while adaptive divergence can be wiped out by gene flow, new adaptive variation can be introduced via introgression. The relative frequency of these outcomes, and indeed the frequency of hybridization and introgression in general are largely unknown. One group of closely-related species with several documented cases of hybridization is the Mediterranean ragwort (genus: Senecio) species-complex. Examples of both polyploid and homoploid hybrid speciation are known in the clade, although their evolutionary relationships and the general frequency of introgressive hybridization among them remain unknown. Using a whole genome gene-space dataset comprising eight Senecio species we fully resolve the phylogeny of these species for the first time despite phylogenetic incongruence across the genome. Using a D-statistic approach, we demonstrate previously unknown cases of introgressive hybridization between multiple pairs of taxa across the species tree. This is an important step in establishing these species as a study system for diversification with gene flow, and suggests that introgressive hybridization may be a widespread and important process in plant evolution.
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Affiliation(s)
- Owen G Osborne
- Department of Plant Sciences, University of Oxford, Oxford, United Kingdom Department of Life Sciences, Imperial College London - Silwood Park Campus, Berkshire, United Kingdom
| | - Mark A Chapman
- Department of Plant Sciences, University of Oxford, Oxford, United Kingdom Department of Life Sciences, Imperial College London - Silwood Park Campus, Berkshire, United Kingdom Centre for Biological Sciences, Faculty of Natural & Environmental Sciences, University of Southampton, Southampton, United Kingdom
| | - Bruno Nevado
- Department of Plant Sciences, University of Oxford, Oxford, United Kingdom
| | - Dmitry A Filatov
- Department of Plant Sciences, University of Oxford, Oxford, United Kingdom
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27
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Rougemont Q, Roux C, Neuenschwander S, Goudet J, Launey S, Evanno G. Reconstructing the demographic history of divergence between European river and brook lampreys using approximate Bayesian computations. PeerJ 2016; 4:e1910. [PMID: 27077007 PMCID: PMC4830234 DOI: 10.7717/peerj.1910] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Accepted: 03/17/2016] [Indexed: 12/19/2022] Open
Abstract
Inferring the history of isolation and gene flow during species divergence is a central question in evolutionary biology. The European river lamprey (Lampetra fluviatilis) and brook lamprey (L. planeri) show a low reproductive isolation but have highly distinct life histories, the former being parasitic-anadromous and the latter non-parasitic and freshwater resident. Here we used microsatellite data from six replicated population pairs to reconstruct their history of divergence using an approximate Bayesian computation framework combined with a random forest model. In most population pairs, scenarios of divergence with recent isolation were outcompeted by scenarios proposing ongoing gene flow, namely the Secondary Contact (SC) and Isolation with Migration (IM) models. The estimation of demographic parameters under the SC model indicated a time of secondary contact close to the time of speciation, explaining why SC and IM models could not be discriminated. In case of an ancient secondary contact, the historical signal of divergence is lost and neutral markers converge to the same equilibrium as under the less parameterized model allowing ongoing gene flow. Our results imply that models of secondary contacts should be systematically compared to models of divergence with gene flow; given the difficulty to discriminate among these models, we suggest that genome-wide data are needed to adequately reconstruct divergence history.
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Affiliation(s)
- Quentin Rougemont
- UMR 985 Ecologie et Santé des Ecosystèmes, Institut National de la Recherche Agronomique, Rennes, France
- UMR 985 Ecologie et Santé des Ecosystèmes, Agrocampus Ouest, Rennes, France
| | - Camille Roux
- Department of Ecology and Evolution, Université de Lausanne, Lausanne, Switzerland
| | - Samuel Neuenschwander
- Department of Ecology and Evolution, Université de Lausanne, Lausanne, Switzerland
- Swiss Institute of Bioinformatics, Vital-IT, Lausanne, Switzerland
| | - Jérôme Goudet
- Department of Ecology and Evolution, Université de Lausanne, Lausanne, Switzerland
| | - Sophie Launey
- UMR 985 Ecologie et Santé des Ecosystèmes, Institut National de la Recherche Agronomique, Rennes, France
- UMR 985 Ecologie et Santé des Ecosystèmes, Agrocampus Ouest, Rennes, France
| | - Guillaume Evanno
- UMR 985 Ecologie et Santé des Ecosystèmes, Institut National de la Recherche Agronomique, Rennes, France
- UMR 985 Ecologie et Santé des Ecosystèmes, Agrocampus Ouest, Rennes, France
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28
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Harrison RG, Larson EL. Heterogeneous genome divergence, differential introgression, and the origin and structure of hybrid zones. Mol Ecol 2016; 25:2454-66. [PMID: 26857437 DOI: 10.1111/mec.13582] [Citation(s) in RCA: 125] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Revised: 01/19/2016] [Accepted: 01/25/2016] [Indexed: 12/16/2022]
Abstract
Hybrid zones have been promoted as windows on the evolutionary process and as laboratories for studying divergence and speciation. Patterns of divergence between hybridizing species can now be characterized on a genomewide scale, and recent genome scans have focused on the presence of 'islands' of divergence. Patterns of heterogeneous genomic divergence may reflect differential introgression following secondary contact and provide insights into which genome regions contribute to local adaptation, hybrid unfitness and positive assortative mating. However, heterogeneous genome divergence can also arise in the absence of any gene flow, as a result of variation in selection and recombination across the genome. We suggest that to understand hybrid zone origins and dynamics, it is essential to distinguish between genome regions that are divergent between pure parental populations and regions that show restricted introgression where these populations interact in hybrid zones. The latter, more so than the former, reveal the likely genetic architecture of reproductive isolation. Mosaic hybrid zones, because of their complex structure and multiple contacts, are particularly good subjects for distinguishing primary intergradation from secondary contact. Comparisons among independent hybrid zones or transects that involve the 'same' species pair can also help to distinguish between divergence with gene flow and secondary contact. However, data from replicate hybrid zones or replicate transects do not reveal consistent patterns; in a few cases, patterns of introgression are similar across independent transects, but for many taxa, there is distinct lack of concordance, presumably due to variation in environmental context and/or variation in the genetics of the interacting populations.
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Affiliation(s)
- Richard G Harrison
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, 14853, USA
| | - Erica L Larson
- Division of Biological Sciences, University of Montana, Missoula, MT, 59812, USA
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29
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The genome sequence of the outbreeding globe artichoke constructed de novo incorporating a phase-aware low-pass sequencing strategy of F1 progeny. Sci Rep 2016; 6:19427. [PMID: 26786968 PMCID: PMC4726258 DOI: 10.1038/srep19427] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 12/11/2015] [Indexed: 12/13/2022] Open
Abstract
Globe artichoke (Cynara cardunculus var. scolymus) is an out-crossing, perennial, multi-use crop species that is grown worldwide and belongs to the Compositae, one of the most successful Angiosperm families. We describe the first genome sequence of globe artichoke. The assembly, comprising of 13,588 scaffolds covering 725 of the 1,084 Mb genome, was generated using ~133-fold Illumina sequencing data and encodes 26,889 predicted genes. Re-sequencing (30×) of globe artichoke and cultivated cardoon (C. cardunculus var. altilis) parental genotypes and low-coverage (0.5 to 1×) genotyping-by-sequencing of 163 F1 individuals resulted in 73% of the assembled genome being anchored in 2,178 genetic bins ordered along 17 chromosomal pseudomolecules. This was achieved using a novel pipeline, SOILoCo (Scaffold Ordering by Imputation with Low Coverage), to detect heterozygous regions and assign parental haplotypes with low sequencing read depth and of unknown phase. SOILoCo provides a powerful tool for de novo genome analysis of outcrossing species. Our data will enable genome-scale analyses of evolutionary processes among crops, weeds, and wild species within and beyond the Compositae, and will facilitate the identification of economically important genes from related species.
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30
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Derevnina L, Chin-Wo-Reyes S, Martin F, Wood K, Froenicke L, Spring O, Michelmore R. Genome Sequence and Architecture of the Tobacco Downy Mildew Pathogen Peronospora tabacina. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2015; 28:1198-215. [PMID: 26196322 DOI: 10.1094/mpmi-05-15-0112-r] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Peronospora tabacina is an obligate biotrophic oomycete that causes blue mold or downy mildew on tobacco (Nicotiana tabacum). It is an economically important disease occurring frequently in tobacco-growing regions worldwide. We sequenced and characterized the genomes of two P. tabacina isolates and mined them for pathogenicity-related proteins and effector-encoding genes. De novo assembly of the genomes using Illumina reads resulted in 4,016 (63.1 Mb, N50 = 79 kb) and 3,245 (55.3 Mb, N50 = 61 kb) scaffolds for isolates 968-J2 and 968-S26, respectively, with an estimated genome size of 68 Mb. The mitochondrial genome has a similar size (approximately 43 kb) and structure to those of other oomycetes, plus several minor unique features. Repetitive elements, primarily retrotransposons, make up approximately 24% of the nuclear genome. Approximately 18,000 protein-coding gene models were predicted. Mining the secretome revealed approximately 120 candidate RxLR, six CRN (candidate effectors that elicit crinkling and necrosis), and 61 WY domain-containing proteins. Candidate RxLR effectors were shown to be predominantly undergoing diversifying selection, with approximately 57% located in variable gene-sparse regions of the genome. Aligning the P. tabacina genome to Hyaloperonospora arabidopsidis and Phytophthora spp. revealed a high level of synteny. Blocks of synteny show gene inversions and instances of expansion in intergenic regions. Extensive rearrangements of the gene-rich genomic regions do not appear to have occurred during the evolution of these highly variable pathogens. These assemblies provide the basis for studies of virulence in this and other downy mildew pathogens.
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Affiliation(s)
- Lida Derevnina
- 1 Genome Center, University of California Davis, Davis, CA, U.S.A
| | | | - Frank Martin
- 2 United States Department of Agriculture-Agricultural Research Service, Salinas, CA U.S.A
| | - Kelsey Wood
- 1 Genome Center, University of California Davis, Davis, CA, U.S.A
| | - Lutz Froenicke
- 1 Genome Center, University of California Davis, Davis, CA, U.S.A
| | - Otmar Spring
- 3 Institute of Botany, University of Hohenheim, Germany
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31
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Testo WL, Watkins JE, Barrington DS. Dynamics of asymmetrical hybridization in North American wood ferns: reconciling patterns of inheritance with gametophyte reproductive biology. THE NEW PHYTOLOGIST 2015; 206:785-795. [PMID: 25443156 DOI: 10.1111/nph.13213] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Accepted: 11/11/2014] [Indexed: 06/04/2023]
Abstract
Hybridization is an important evolutionary force in plants, but the mechanisms underlying it have not been well studied for many groups. In particular, the drivers of non-random patterns of interspecific gene flow (asymmetrical hybridization) remain poorly understood, especially in the seed-free vascular plants. Here, we examine patterns of asymmetrical hybridization in two widespread fern hybrids from eastern North America and study the role of gametophyte ecology in the determination of hybridization bias. We characterized the maternal parentage of > 140 hybrid sporophytes by sequencing a c. 350-bp region of chloroplast DNA (cpDNA). To identify factors contributing to patterns of asymmetrical hybridization, we cultured gametophytes of the parental species and evaluated critical aspects of their reproductive biology. We found that asymmetrical hybridization was prevalent across the populations of both hybrids. Reproductive traits varied across species and suggest that selfing potential, antheridiogen responsiveness, sperm dispersal capacity and gamete size all contribute to the mediation of the direction of hybridization in this group. Our findings suggest that asymmetrical hybridization in ferns is driven by an array of reproductive traits. This study helps to sharpen and define a mechanistic understanding of patterns of hybridization in this group and demonstrates the importance of considering gametophyte biology when studying evolutionary processes in ferns.
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Affiliation(s)
- Weston L Testo
- Department of Plant Biology, University of Vermont, 111 Jeffords Hall, 63 Carrigan Drive, Burlington, VT, 05405, USA
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32
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Strong postzygotic isolation prevents introgression between two hybridizing Neotropical orchids, Epidendrum denticulatum and E. fulgens. Evol Ecol 2015. [DOI: 10.1007/s10682-015-9753-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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33
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Carneiro M, Albert FW, Afonso S, Pereira RJ, Burbano H, Campos R, Melo-Ferreira J, Blanco-Aguiar JA, Villafuerte R, Nachman MW, Good JM, Ferrand N. The genomic architecture of population divergence between subspecies of the European rabbit. PLoS Genet 2014; 10:e1003519. [PMID: 25166595 PMCID: PMC4148185 DOI: 10.1371/journal.pgen.1003519] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Accepted: 04/06/2013] [Indexed: 11/18/2022] Open
Abstract
The analysis of introgression of genomic regions between divergent populations provides an excellent opportunity to determine the genetic basis of reproductive isolation during the early stages of speciation. However, hybridization and subsequent gene flow must be relatively common in order to localize individual loci that resist introgression. In this study, we used next-generation sequencing to study genome-wide patterns of genetic differentiation between two hybridizing subspecies of rabbits (Oryctolagus cuniculus algirus and O. c. cuniculus) that are known to undergo high rates of gene exchange. Our primary objective was to identify specific genes or genomic regions that have resisted introgression and are likely to confer reproductive barriers in natural conditions. On the basis of 326,000 polymorphisms, we found low to moderate overall levels of differentiation between subspecies, and fewer than 200 genomic regions dispersed throughout the genome showing high differentiation consistent with a signature of reduced gene flow. Most differentiated regions were smaller than 200 Kb and contained very few genes. Remarkably, 30 regions were each found to contain a single gene, facilitating the identification of candidate genes underlying reproductive isolation. This gene-level resolution yielded several insights into the genetic basis and architecture of reproductive isolation in rabbits. Regions of high differentiation were enriched on the X-chromosome and near centromeres. Genes lying within differentiated regions were often associated with transcription and epigenetic activities, including chromatin organization, regulation of transcription, and DNA binding. Overall, our results from a naturally hybridizing system share important commonalities with hybrid incompatibility genes identified using laboratory crosses in mice and flies, highlighting general mechanisms underlying the maintenance of reproductive barriers.
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Affiliation(s)
- Miguel Carneiro
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Campus Agrário de Vairão, Vairão, Portugal
- Departamento de Biologia, Faculdade de Ciências Universidade do Porto, Porto, Portugal
- * E-mail:
| | - Frank W. Albert
- Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
- Princeton University, Lewis Sigler Institute for Integrative Genomics, Princeton, New Jersey, United States of America
| | - Sandra Afonso
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Campus Agrário de Vairão, Vairão, Portugal
| | - Ricardo J. Pereira
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Campus Agrário de Vairão, Vairão, Portugal
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, United States of America
| | - Hernan Burbano
- Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
- Department of Molecular Biology, Max Planck Institute for Developmental Biology, Tuebingen, Germany
| | - Rita Campos
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Campus Agrário de Vairão, Vairão, Portugal
| | - José Melo-Ferreira
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Campus Agrário de Vairão, Vairão, Portugal
| | - Jose A. Blanco-Aguiar
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Campus Agrário de Vairão, Vairão, Portugal
- IREC, Instituto de Investigación en Recursos Cinegéticos (CSIC-UCLM-JCCM), Ciudad Real, Spain
| | - Rafael Villafuerte
- Instituto de Investigación en Recursos Cinegéticos (CSIC-UCLM-JCCM), Departamento de Zoología, Universidad de Córdoba, Córdoba, Spain
| | - Michael W. Nachman
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, Arizona, United States of America
| | - Jeffrey M. Good
- Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
- Division of Biological Sciences, The University of Montana, Missoula, Montana, United States of America
| | - Nuno Ferrand
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Campus Agrário de Vairão, Vairão, Portugal
- Departamento de Biologia, Faculdade de Ciências Universidade do Porto, Porto, Portugal
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Springer MS, Gatesy J. Land plant origins and coalescence confusion. TRENDS IN PLANT SCIENCE 2014; 19:267-269. [PMID: 24641875 DOI: 10.1016/j.tplants.2014.02.012] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Revised: 01/30/2014] [Accepted: 02/20/2014] [Indexed: 06/03/2023]
Affiliation(s)
- Mark S Springer
- Department of Biology, University of California, Riverside, CA 92521, USA.
| | - John Gatesy
- Department of Biology, University of California, Riverside, CA 92521, USA.
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Osborne OG, Batstone TE, Hiscock SJ, Filatov DA. Rapid speciation with gene flow following the formation of Mt. Etna. Genome Biol Evol 2014; 5:1704-15. [PMID: 23973865 PMCID: PMC3787679 DOI: 10.1093/gbe/evt127] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Environmental or geological changes can create new niches that drive ecological species divergence without the immediate cessation of gene flow. However, few such cases have been characterized. On a recently formed volcano, Mt. Etna, Senecio aethnensis and S. chrysanthemifolius inhabit contrasting environments of high and low altitude, respectively. They have very distinct phenotypes, despite hybridizing promiscuously, and thus may represent an important example of ecological speciation “in action,” possibly as a response to the rapid geological changes that Mt. Etna has recently undergone. To elucidate the species’ evolutionary history, and help establish the species as a study system for speciation genomics, we sequenced the transcriptomes of the two Etnean species, and the outgroup, S. vernalis, using Illumina sequencing. Despite the species’ substantial phenotypic divergence, synonymous divergence between the high- and low-altitude species was low (dS = 0.016 ± 0.017 [SD]). A comparison of species divergence models with and without gene flow provided unequivocal support in favor of the former and demonstrated a recent time of species divergence (153,080 ya ± 11,470 [SE]) that coincides with the growth of Mt. Etna to the altitudes that separate the species today. Analysis of dN/dS revealed wide variation in selective constraint between genes, and evidence that highly expressed genes, more “multifunctional” genes, and those with more paralogs were under elevated purifying selection. Taken together, these results are consistent with a model of ecological speciation, potentially as a response to the emergence of a new, high-altitude niche as the volcano grew.
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Affiliation(s)
- Owen G Osborne
- Department of Plant Sciences, University of Oxford, Oxford, United Kingdom
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36
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Vitte C, Fustier MA, Alix K, Tenaillon MI. The bright side of transposons in crop evolution. Brief Funct Genomics 2014; 13:276-95. [PMID: 24681749 DOI: 10.1093/bfgp/elu002] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The past decades have revealed an unexpected yet prominent role of so-called 'junk DNA' in the regulation of gene expression, thereby challenging our view of the mechanisms underlying phenotypic evolution. In particular, several mechanisms through which transposable elements (TEs) participate in functional genome diversity have been depicted, bringing to light the 'TEs bright side'. However, the relative contribution of those mechanisms and, more generally, the importance of TE-based polymorphisms on past and present phenotypic variation in crops species remain poorly understood. Here, we review current knowledge on both issues, and discuss how analyses of massively parallel sequencing data combined with statistical methodologies and functional validations will help unravelling the impact of TEs on crop evolution in a near future.
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Hasselman DJ, Argo EE, McBride MC, Bentzen P, Schultz TF, Perez-Umphrey AA, Palkovacs EP. Human disturbance causes the formation of a hybrid swarm between two naturally sympatric fish species. Mol Ecol 2014; 23:1137-52. [PMID: 24450302 DOI: 10.1111/mec.12674] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Revised: 01/13/2014] [Accepted: 01/17/2014] [Indexed: 11/28/2022]
Affiliation(s)
- Daniel J. Hasselman
- Department of Ecology and Evolutionary Biology; University of California; Santa Cruz CA 95060 USA
| | - Emily E. Argo
- Department of Ecology and Evolutionary Biology; University of California; Santa Cruz CA 95060 USA
| | - Meghan C. McBride
- Marine Gene Probe Laboratory; Biology Department; Dalhousie University; Halifax NS B3H 4R2 Canada
| | - Paul Bentzen
- Marine Gene Probe Laboratory; Biology Department; Dalhousie University; Halifax NS B3H 4R2 Canada
| | - Thomas F. Schultz
- Marine Conservation Molecular Facility; Duke University Marine Laboratory; Beaufort NC 28516 USA
| | - Anna A. Perez-Umphrey
- Marine Conservation Molecular Facility; Duke University Marine Laboratory; Beaufort NC 28516 USA
| | - Eric P. Palkovacs
- Department of Ecology and Evolutionary Biology; University of California; Santa Cruz CA 95060 USA
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38
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Genomic islands of divergence are not affected by geography of speciation in sunflowers. Nat Commun 2013; 4:1827. [PMID: 23652015 DOI: 10.1038/ncomms2833] [Citation(s) in RCA: 209] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Accepted: 04/04/2013] [Indexed: 01/28/2023] Open
Abstract
Genomic studies of speciation often report the presence of highly differentiated genomic regions interspersed within a milieu of weakly diverged loci. The formation of these speciation islands is generally attributed to reduced inter-population gene flow near loci under divergent selection, but few studies have critically evaluated this hypothesis. Here, we report on transcriptome scans among four recently diverged pairs of sunflower (Helianthus) species that vary in the geographical context of speciation. We find that genetic divergence is lower in sympatric and parapatric comparisons, consistent with a role for gene flow in eroding neutral differences. However, genomic islands of divergence are numerous and small in all comparisons, and contrary to expectations, island number and size are not significantly affected by levels of interspecific gene flow. Rather, island formation is strongly associated with reduced recombination rates. Overall, our results indicate that the functional architecture of genomes plays a larger role in shaping genomic divergence than does the geography of speciation.
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Butlin RK, Saura M, Charrier G, Jackson B, André C, Caballero A, Coyne JA, Galindo J, Grahame JW, Hollander J, Kemppainen P, Martínez-Fernández M, Panova M, Quesada H, Johannesson K, Rolán-Alvarez E. Parallel evolution of local adaptation and reproductive isolation in the face of gene flow. Evolution 2013; 68:935-49. [PMID: 24299519 PMCID: PMC4261988 DOI: 10.1111/evo.12329] [Citation(s) in RCA: 118] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Accepted: 11/06/2013] [Indexed: 01/28/2023]
Abstract
Parallel evolution of similar phenotypes provides strong evidence for the operation of natural selection. Where these phenotypes contribute to reproductive isolation, they further support a role for divergent, habitat-associated selection in speciation. However, the observation of pairs of divergent ecotypes currently occupying contrasting habitats in distinct geographical regions is not sufficient to infer parallel origins. Here we show striking parallel phenotypic divergence between populations of the rocky-shore gastropod, Littorina saxatilis, occupying contrasting habitats exposed to either wave action or crab predation. This divergence is associated with barriers to gene exchange but, nevertheless, genetic variation is more strongly structured by geography than by ecotype. Using approximate Bayesian analysis of sequence data and amplified fragment length polymorphism markers, we show that the ecotypes are likely to have arisen in the face of continuous gene flow and that the demographic separation of ecotypes has occurred in parallel at both regional and local scales. Parameter estimates suggest a long delay between colonization of a locality and ecotype formation, perhaps because the postglacial spread of crab populations was slower than the spread of snails. Adaptive differentiation may not be fully genetically independent despite being demographically parallel. These results provide new insight into a major model of ecologically driven speciation.
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Affiliation(s)
- Roger K Butlin
- Animal and Plant Sciences, The University of Sheffield, Sheffield S10 2TN, United Kingdom; Biological and Environmental Sciences-Tjärnö, University of Gothenburg, SE-452 96, Strömstad, Sweden.
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40
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Feder JL, Flaxman SM, Egan SP, Comeault AA, Nosil P. Geographic Mode of Speciation and Genomic Divergence. ANNUAL REVIEW OF ECOLOGY EVOLUTION AND SYSTEMATICS 2013. [DOI: 10.1146/annurev-ecolsys-110512-135825] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Jeffrey L. Feder
- Department of Biological Sciences,
- Environmental Change Initiative, and
- Advanced Diagnostics and Therapeutics, University of Notre Dame, Notre Dame, Indiana 46556; ,
| | - Samuel M. Flaxman
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, Colorado 80309;
| | - Scott P. Egan
- Department of Biological Sciences,
- Advanced Diagnostics and Therapeutics, University of Notre Dame, Notre Dame, Indiana 46556; ,
| | - Aaron A. Comeault
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, S102TN, United Kingdom; ,
| | - Patrik Nosil
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, S102TN, United Kingdom; ,
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Abstract
BACKGROUND Our understanding of the processes and dynamics of allopolyploid speciation, the long-term consequences of ploidal change, and the genetic and chromosomal changes in new emerged allopolyploids has substantially increased during the past few decades. Yet we remain uncertain about the time since lineage divergence when two taxa are capable of spawning such entities. Indeed, the matter has seemed intractable. Knowledge of the window of opportunity for allopolyploid production is very important because it provides temporal insight into a key evolutionary process, and a temporal reference against which other modes of speciation may be measured. SCOPE This Viewpoint paper reviews and integrates published information on the crossability of herbaceous species and the fertility of their hybrids in relation to species' divergence times. Despite limitations in methodology and sampling, the estimated times to hybrid sterility are somewhat congruent across disparate lineages. Whereas the waiting time for hybrid sterility is roughly 4-5 million years, the waiting time for cross-incompatibility is roughly 8-10 million years, sometimes considerably more. Strict allopolyploids may be formed in the intervening time window. The progenitors of several allopolyploids diverged between 4 and 6 million years before allopolyploid synthesis, as expected. This is the first study to propose a general temporal framework for strict allopolyploidy. This Viewpoint paper hopefully will stimulate interest in studying the tempo of speciation and the tempo of reproductive isolation in general.
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42
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Chapman MA, Hiscock SJ, Filatov DA. Genomic divergence during speciation driven by adaptation to altitude. Mol Biol Evol 2013; 30:2553-67. [PMID: 24077768 PMCID: PMC3840311 DOI: 10.1093/molbev/mst168] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Even though Darwin's "On the Origin of Species" implied selection being the main driver of species formation, the role of natural selection in speciation remains poorly understood. In particular, it remains unclear how selection at a few genes can lead to genomewide divergence and the formation of distinct species. We used a particularly attractive clear-cut case of recent plant ecological speciation to investigate the demography and genomic bases of species formation driven by adaptation to contrasting conditions. High-altitude Senecio aethnensis and low-altitude S. chrysanthemifolius live at the extremes of a mountain slope on Mt. Etna, Sicily, and form a hybrid zone at intermediate altitudes but remain morphologically distinct. Genetic differentiation of these species was analyzed at the DNA polymorphism and gene expression levels by high-throughput sequencing of transcriptomes from multiple individuals. Out of ≈ 18,000 genes analyzed, only a small number (90) displayed differential expression between the two species. These genes showed significantly elevated species differentiation (FST and Dxy), consistent with diversifying selection acting on these genes. Genomewide genetic differentiation of the species is surprisingly low (FST = 0.19), while ≈ 200 genes showed significantly higher (false discovery rate < 1%; mean outlier FST > 0.6) interspecific differentiation and evidence for local adaptation. Diversifying selection at only a handful of loci may be enough for the formation and maintenance of taxonomically well-defined species, despite ongoing gene flow. This provides an explanation of why many closely related species (in plants, in particular) remain phenotypically and ecologically distinct despite ongoing hybridization, a question that has long puzzled naturalists and geneticists alike.
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Affiliation(s)
- Mark A Chapman
- Department of Plant Sciences, University of Oxford, Oxford, United Kingdom
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43
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Signatures of demography and recombination at coding genes in naturally-distributed populations of Arabidopsis lyrata subsp. petraea. PLoS One 2013; 8:e58916. [PMID: 23554957 PMCID: PMC3595216 DOI: 10.1371/journal.pone.0058916] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Accepted: 02/08/2013] [Indexed: 11/19/2022] Open
Abstract
Demography impacts the observed standing level of genetic diversity present in populations. Distinguishing the relative impacts of demography from selection requires a baseline of expressed gene variation in naturally occurring populations. Six nuclear genes were sequenced to estimate the patterns and levels of genetic diversity in natural Arabidopsis lyrata subsp. petraea populations that differ in demographic histories since the Pleistocene. As expected, northern European populations have genetic signatures of a strong population bottleneck likely due to glaciation during the Pleistocene. Levels of diversity in the northern populations are about half of that in central European populations. Bayesian estimates of historical population size changes indicate that central European populations also have signatures of population size change since the last glacial maxima, suggesting that these populations are not as stable as previously thought. Time since divergence amongst northern European populations is higher than amongst central European populations, suggesting that the northern European populations were established before the Pleistocene and survived glaciation in small separated refugia. Estimates of demography based on expressed genes are complementary to estimates based on microsatellites and transposable elements, elucidating temporal shifts in population dynamics and confirming the importance of marker selection for tests of demography.
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44
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Mamidi S, Rossi M, Moghaddam SM, Annam D, Lee R, Papa R, McClean PE. Demographic factors shaped diversity in the two gene pools of wild common bean Phaseolus vulgaris L. Heredity (Edinb) 2013; 110:267-76. [PMID: 23169559 PMCID: PMC3668653 DOI: 10.1038/hdy.2012.82] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2012] [Revised: 05/31/2012] [Accepted: 06/29/2012] [Indexed: 11/09/2022] Open
Abstract
Wild common bean (Phaseolus vulgaris L.) is distributed throughout the Americas from Mexico to northern Argentina. Within this range, the species is divided into two gene pools (Andean and Middle American) along a latitudinal gradient. The diversity of 24 wild common bean genotypes from throughout the geographic range of the species was described by using sequence data from 13 loci. An isolation-migration model was evaluated using a coalescent analysis to estimate multiple demographic parameters. Using a Bayesian approach, Andean and Middle American subpopulations with high percentage of parentages were observed. Over all loci, the Middle American gene pool was more diverse than the Andean gene pool (π(sil)=0.0089 vs 0.0068). The two subpopulations were strongly genetically differentiated over all loci (F(st)=0.29). It is estimated that the two current wild gene pools diverged from a common ancestor ∼111 000 years ago. Subsequently, each gene pool underwent a bottleneck immediately after divergence and lasted ∼40 000 years. The Middle American bottleneck population size was ∼46% of the ancestral population size, whereas the Andean was 26%. Continuous asymmetric gene flow was detected between the two gene pools with a larger number of migrants entering Middle American gene pool from the Andean gene pool. These results suggest that because of the complex population structure associated with the ancestral divergence, subsequent bottlenecks in each gene pool, gene pool-specific domestication and intense selection within each gene pool by breeders; association mapping would best be practised within each common bean gene pool.
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Affiliation(s)
- S Mamidi
- Genomics and Bioinformatics Program, North Dakota State University, Fargo, ND, USA
- Department of Plant Sciences, North Dakota State University, Fargo, ND, USA
| | - M Rossi
- Dipartimento di Scienze Agrarie, Alimentari ed Ambientali, Università Politecnica delle Marche, Ancona, Italy
| | - S M Moghaddam
- Genomics and Bioinformatics Program, North Dakota State University, Fargo, ND, USA
- Department of Plant Sciences, North Dakota State University, Fargo, ND, USA
| | - D Annam
- Department of Statistics, North Dakota State University, Fargo, ND, USA
| | - R Lee
- Genomics and Bioinformatics Program, North Dakota State University, Fargo, ND, USA
- Department of Plant Sciences, North Dakota State University, Fargo, ND, USA
| | - R Papa
- Dipartimento di Scienze Agrarie, Alimentari ed Ambientali, Università Politecnica delle Marche, Ancona, Italy
- Cereal Research Centre, Agricultural Research Council (CRA-CER), Foggia, Italy
| | - P E McClean
- Genomics and Bioinformatics Program, North Dakota State University, Fargo, ND, USA
- Department of Plant Sciences, North Dakota State University, Fargo, ND, USA
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45
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Strasburg JL, Rieseberg LH. Methodological challenges to realizing the potential of hybridization research. J Evol Biol 2013; 26:259-60. [DOI: 10.1111/jeb.12006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Accepted: 09/01/2012] [Indexed: 01/13/2023]
Affiliation(s)
- J. L. Strasburg
- Department of Biology; University of Minnesota-Duluth; Duluth MN USA
| | - L. H. Rieseberg
- Department of Biology; Indiana University; Bloomington IN USA
- Department of Botany; University of British Columbia; Vancouver BC Canada
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46
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Renaut S, Grassa CJ, Moyers BT, Kane NC, Rieseberg LH. The Population Genomics of Sunflowers and Genomic Determinants of Protein Evolution Revealed by RNAseq. BIOLOGY 2012; 1:575-96. [PMID: 24832509 PMCID: PMC4009819 DOI: 10.3390/biology1030575] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Revised: 10/09/2012] [Accepted: 10/12/2012] [Indexed: 11/17/2022]
Abstract
Few studies have investigated the causes of evolutionary rate variation among plant nuclear genes, especially in recently diverged species still capable of hybridizing in the wild. The recent advent of Next Generation Sequencing (NGS) permits investigation of genome wide rates of protein evolution and the role of selection in generating and maintaining divergence. Here, we use individual whole-transcriptome sequencing (RNAseq) to refine our understanding of the population genomics of wild species of sunflowers (Helianthus spp.) and the factors that affect rates of protein evolution. We aligned 35 GB of transcriptome sequencing data and identified 433,257 polymorphic sites (SNPs) in a reference transcriptome comprising 16,312 genes. Using SNP markers, we identified strong population clustering largely corresponding to the three species analyzed here (Helianthus annuus, H. petiolaris, H. debilis), with one distinct early generation hybrid. Then, we calculated the proportions of adaptive substitution fixed by selection (alpha) and identified gene ontology categories with elevated values of alpha. The “response to biotic stimulus” category had the highest mean alpha across the three interspecific comparisons, implying that natural selection imposed by other organisms plays an important role in driving protein evolution in wild sunflowers. Finally, we examined the relationship between protein evolution (dN/dS ratio) and several genomic factors predicted to co-vary with protein evolution (gene expression level, divergence and specificity, genetic divergence [FST], and nucleotide diversity pi). We find that variation in rates of protein divergence was correlated with gene expression level and specificity, consistent with results from a broad range of taxa and timescales. This would in turn imply that these factors govern protein evolution both at a microevolutionary and macroevolutionary timescale. Our results contribute to a general understanding of the determinants of rates of protein evolution and the impact of selection on patterns of polymorphism and divergence.
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Affiliation(s)
- Sébastien Renaut
- Department of Botany, University of British Columbia, 3529-6270 University Boulevard, Vancouver, BC V6T 1Z4, Canada.
| | - Christopher J Grassa
- Department of Botany, University of British Columbia, 3529-6270 University Boulevard, Vancouver, BC V6T 1Z4, Canada
| | - Brook T Moyers
- Department of Botany, University of British Columbia, 3529-6270 University Boulevard, Vancouver, BC V6T 1Z4, Canada
| | - Nolan C Kane
- Department of Botany, University of British Columbia, 3529-6270 University Boulevard, Vancouver, BC V6T 1Z4, Canada
| | - Loren H Rieseberg
- Department of Botany, University of British Columbia, 3529-6270 University Boulevard, Vancouver, BC V6T 1Z4, Canada
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47
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Andrew RL, Kane NC, Baute GJ, Grassa CJ, Rieseberg LH. Recent nonhybrid origin of sunflower ecotypes in a novel habitat. Mol Ecol 2012; 22:799-813. [DOI: 10.1111/mec.12038] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Revised: 07/27/2012] [Accepted: 07/30/2012] [Indexed: 02/04/2023]
Affiliation(s)
- Rose L. Andrew
- Department of Botany; University of British Columbia; 3529-6270 University Blvd; Vancouver; BC; Canada; V6T 1Z4
| | - Nolan C. Kane
- Department of Botany; University of British Columbia; 3529-6270 University Blvd; Vancouver; BC; Canada; V6T 1Z4
| | - Greg J. Baute
- Department of Botany; University of British Columbia; 3529-6270 University Blvd; Vancouver; BC; Canada; V6T 1Z4
| | - Christopher J. Grassa
- Department of Botany; University of British Columbia; 3529-6270 University Blvd; Vancouver; BC; Canada; V6T 1Z4
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48
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Kane NC, Burke JM, Marek L, Seiler G, Vear F, Baute G, Knapp SJ, Vincourt P, Rieseberg LH. Sunflower genetic, genomic and ecological resources. Mol Ecol Resour 2012; 13:10-20. [PMID: 23039950 DOI: 10.1111/1755-0998.12023] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2011] [Revised: 08/22/2012] [Accepted: 08/24/2012] [Indexed: 11/29/2022]
Abstract
Long a major focus of genetic research and breeding, sunflowers (Helianthus) are emerging as an increasingly important experimental system for ecological and evolutionary studies. Here, we review the various attributes of wild and domesticated sunflowers that make them valuable for ecological experimentation and describe the numerous publicly available resources that have enabled rapid advances in ecological and evolutionary genetics. Resources include seed collections available from germplasm centres at the USDA and INRA, genomic and EST sequences, mapping populations, genetic markers, genetic and physical maps and other forward- and reverse-genetic tools. We also discuss some of the key evolutionary, genetic and ecological questions being addressed in sunflowers, as well as gaps in our knowledge and promising areas for future research.
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Affiliation(s)
- Nolan C Kane
- Department of Ecology and Evolutionary Biology, University of Colorado at Boulder, Boulder, CO 80309, USA.
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49
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Kingston SE, Jernigan RW, Fagan WF, Braun D, Braun MJ. Genomic variation in cline shape across a hybrid zone. Ecol Evol 2012; 2:2737-48. [PMID: 23170209 PMCID: PMC3501626 DOI: 10.1002/ece3.375] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2012] [Revised: 08/13/2012] [Accepted: 08/20/2012] [Indexed: 11/17/2022] Open
Abstract
Hybrid zones are unique biological interfaces that reveal both population level and species level evolutionary processes. A genome-scale approach to assess gene flow across hybrid zones is vital, and now possible. In Mexican towhees (genus Pipilo), several morphological hybrid gradients exist. We completed a genome survey across one such gradient (9 populations, 140 birds) using mitochondrial DNA, 28 isozyme, and 377 AFLP markers. To assess variation in introgression among loci, cline parameters (i.e., width, center) for the 61 clinally varying loci were estimated and compiled into genomic distributions for tests against three empirical models spanning the range of observed cline shape. No single model accounts for observed variation in cline shape among loci. Numerous backcross individuals near the gradient center confirm a hybrid origin for these populations, contrary to a previous hypothesis based on social mimicry and character displacement. In addition, the observed variation does not bin into well-defined categories of locus types (e.g., neutral vs. highly selected). Our multi-locus analysis reveals cross-genomic variation in selective constraints on gene flow and locus-specific flexibility in the permeability of the interspecies membrane.
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Affiliation(s)
- Sarah E Kingston
- Program in Behavior, Ecology, Evolution, and Systematics, University of Maryland College Park, Maryland, 20742, USA ; Vertebrate Zoology, Smithsonian Institution, National Museum of Natural History Washington, District of Columbia, 20013, USA
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50
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Staton SE, Bakken BH, Blackman BK, Chapman MA, Kane NC, Tang S, Ungerer MC, Knapp SJ, Rieseberg LH, Burke JM. The sunflower (Helianthus annuus L.) genome reflects a recent history of biased accumulation of transposable elements. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2012; 72:142-53. [PMID: 22691070 DOI: 10.1111/j.1365-313x.2012.05072.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Aside from polyploidy, transposable elements are the major drivers of genome size increases in plants. Thus, understanding the diversity and evolutionary dynamics of transposable elements in sunflower (Helianthus annuus L.), especially given its large genome size (∼3.5 Gb) and the well-documented cases of amplification of certain transposons within the genus, is of considerable importance for understanding the evolutionary history of this emerging model species. By analyzing approximately 25% of the sunflower genome from random sequence reads and assembled bacterial artificial chromosome (BAC) clones, we show that it is composed of over 81% transposable elements, 77% of which are long terminal repeat (LTR) retrotransposons. Moreover, the LTR retrotransposon fraction in BAC clones harboring genes is disproportionately composed of chromodomain-containing Gypsy LTR retrotransposons ('chromoviruses'), and the majority of the intact chromoviruses contain tandem chromodomain duplications. We show that there is a bias in the efficacy of homologous recombination in removing LTR retrotransposon DNA, thereby providing insight into the mechanisms associated with transposable element (TE) composition in the sunflower genome. We also show that the vast majority of observed LTR retrotransposon insertions have likely occurred since the origin of this species, providing further evidence that biased LTR retrotransposon activity has played a major role in shaping the chromatin and DNA landscape of the sunflower genome. Although our findings on LTR retrotransposon age and structure could be influenced by the selection of the BAC clones analyzed, a global analysis of random sequence reads indicates that the evolutionary patterns described herein apply to the sunflower genome as a whole.
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Affiliation(s)
- S Evan Staton
- Department of Genetics, University of Georgia, Athens, GA 30602, USA
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