1
|
Leal JL, Milesi P, Hodková E, Zhou Q, James J, Eklund DM, Pyhäjärvi T, Salojärvi J, Lascoux M. Complex Polyploids: Origins, Genomic Composition, and Role of Introgressed Alleles. Syst Biol 2024; 73:392-418. [PMID: 38613229 PMCID: PMC11282369 DOI: 10.1093/sysbio/syae012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 12/18/2023] [Accepted: 03/28/2024] [Indexed: 04/14/2024] Open
Abstract
Introgression allows polyploid species to acquire new genomic content from diploid progenitors or from other unrelated diploid or polyploid lineages, contributing to genetic diversity and facilitating adaptive allele discovery. In some cases, high levels of introgression elicit the replacement of large numbers of alleles inherited from the polyploid's ancestral species, profoundly reshaping the polyploid's genomic composition. In such complex polyploids, it is often difficult to determine which taxa were the progenitor species and which taxa provided additional introgressive blocks through subsequent hybridization. Here, we use population-level genomic data to reconstruct the phylogenetic history of Betula pubescens (downy birch), a tetraploid species often assumed to be of allopolyploid origin and which is known to hybridize with at least four other birch species. This was achieved by modeling polyploidization and introgression events under the multispecies coalescent and then using an approximate Bayesian computation rejection algorithm to evaluate and compare competing polyploidization models. We provide evidence that B. pubescens is the outcome of an autoploid genome doubling event in the common ancestor of B. pendula and its extant sister species, B. platyphylla, that took place approximately 178,000-188,000 generations ago. Extensive hybridization with B. pendula, B. nana, and B. humilis followed in the aftermath of autopolyploidization, with the relative contribution of each of these species to the B. pubescens genome varying markedly across the species' range. Functional analysis of B. pubescens loci containing alleles introgressed from B. nana identified multiple genes involved in climate adaptation, while loci containing alleles derived from B. humilis revealed several genes involved in the regulation of meiotic stability and pollen viability in plant species.
Collapse
Affiliation(s)
- J Luis Leal
- Plant Ecology and Evolution, Department of Ecology and Genetics, Uppsala University, Norbyvägen 18D, 75236 Uppsala, Sweden
| | - Pascal Milesi
- Plant Ecology and Evolution, Department of Ecology and Genetics, Uppsala University, Norbyvägen 18D, 75236 Uppsala, Sweden
- Science for Life Laboratory (SciLifeLab), Uppsala University, 75237 Uppsala, Sweden
| | - Eva Hodková
- Plant Ecology and Evolution, Department of Ecology and Genetics, Uppsala University, Norbyvägen 18D, 75236 Uppsala, Sweden
- Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Kamýcká 129, 16521 Prague, Czech Republic
| | - Qiujie Zhou
- Plant Ecology and Evolution, Department of Ecology and Genetics, Uppsala University, Norbyvägen 18D, 75236 Uppsala, Sweden
| | - Jennifer James
- Plant Ecology and Evolution, Department of Ecology and Genetics, Uppsala University, Norbyvägen 18D, 75236 Uppsala, Sweden
| | - D Magnus Eklund
- Physiology and Environmental Toxicology, Department of Organismal Biology, Uppsala University, Norbyvägen 18A, 75236 Uppsala, Sweden
| | - Tanja Pyhäjärvi
- Organismal and Evolutionary Biology Research Program, Faculty of Biological and Environmental Sciences, and Viikki Plant Science Centre, University of Helsinki, P.O. Box 65 (Viikinkaari 1), 00014 Helsinki, Finland
- Department of Forest Sciences, University of Helsinki, 00014 Helsinki, Finland
| | - Jarkko Salojärvi
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
- Organismal and Evolutionary Biology Research Program, Faculty of Biological and Environmental Sciences, and Viikki Plant Science Centre, University of Helsinki, P.O. Box 65 (Viikinkaari 1), 00014 Helsinki, Finland
| | - Martin Lascoux
- Plant Ecology and Evolution, Department of Ecology and Genetics, Uppsala University, Norbyvägen 18D, 75236 Uppsala, Sweden
- Science for Life Laboratory (SciLifeLab), Uppsala University, 75237 Uppsala, Sweden
| |
Collapse
|
2
|
Brown MR, Abbott RJ, Twyford AD. The emerging importance of cross-ploidy hybridisation and introgression. Mol Ecol 2024; 33:e17315. [PMID: 38501394 DOI: 10.1111/mec.17315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 02/21/2024] [Accepted: 02/23/2024] [Indexed: 03/20/2024]
Abstract
Natural hybridisation is now recognised as pervasive in its occurrence across the Tree of Life. Resurgent interest in natural hybridisation fuelled by developments in genomics has led to an improved understanding of the genetic factors that promote or prevent species cross-mating. Despite this body of work overturning many widely held assumptions about the genetic barriers to hybridisation, it is still widely thought that ploidy differences between species will be an absolute barrier to hybridisation and introgression. Here, we revisit this assumption, reviewing findings from surveys of polyploidy and hybridisation in the wild. In a case study in the British flora, 203 hybrids representing 35% of hybrids with suitable data have formed via cross-ploidy matings, while a wider literature search revealed 59 studies (56 in plants and 3 in animals) in which cross-ploidy hybridisation has been confirmed with genetic data. These results show cross-ploidy hybridisation is readily overlooked, and potentially common in some groups. General findings from these studies include strong directionality of hybridisation, with introgression usually towards the higher ploidy parent, and cross-ploidy hybridisation being more likely to involve allopolyploids than autopolyploids. Evidence for adaptive introgression across a ploidy barrier and cases of cross-ploidy hybrid speciation shows the potential for important evolutionary outcomes.
Collapse
Affiliation(s)
- Max R Brown
- Institute of Ecology and Evolution, University of Edinburgh, Edinburgh, UK
- School of Life Sciences, Anglia Ruskin University, Cambridge, UK
| | - Richard J Abbott
- School of Biology, University of St Andrews, St Andrews, Fife, UK
| | - Alex D Twyford
- Institute of Ecology and Evolution, University of Edinburgh, Edinburgh, UK
- Royal Botanical Garden Edinburgh, Edinburgh, UK
| |
Collapse
|
3
|
Zhang H, Ding J, Holstein N, Wang N. Betula mcallisteri sp. nov. (sect. Acuminatae, Betulaceae), a new diploid species overlooked in the wild and in cultivation, and its relation to the widespread B. luminifera. FRONTIERS IN PLANT SCIENCE 2023; 14:1113274. [PMID: 37324661 PMCID: PMC10268003 DOI: 10.3389/fpls.2023.1113274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Accepted: 04/19/2023] [Indexed: 06/17/2023]
Abstract
Taxa are traditionally identified using morphological proxies for groups of evolutionarily isolated populations. These proxies are common characters deemed by taxonomists as significant. However, there is no general rule on which character or sets of characters are appropriate to circumscribe taxa, leading to discussions and uncertainty. Birch species are notoriously hard to identify due to strong morphological variability and factors such as hybridization and the existence of several ploidy levels. Here, we present evidence for an evolutionarily isolated line of birches from China that are not distinguishable by traditionally assumed taxon recognition proxies, such as fruit or leaf characters. We have discovered that some wild material in China and some cultivated in the Royal Botanic Gardens Edinburgh, formerly recognized as Betula luminifera, differ from other individuals by having a peeling bark and a lack of cambial fragrance. We use restriction site-associated DNA sequencing and flow cytometry to study the evolutionary status of the unidentified Betula samples to assess the extent of hybridization between the unidentified Betula samples and typical B. luminifera in natural populations. Molecular analyses show the unidentified Betula samples as a distinct lineage and reveal very little genetic admixture between the unidentified samples and B. luminifera. This may also be facilitated by the finding that B. luminifera is tetraploid, while the unidentified samples turned out to be diploid. We therefore conclude that the samples represent a yet unrecognized species, which is here described as Betula mcallisteri.
Collapse
Affiliation(s)
- Huayu Zhang
- State Forestry and Grassland Administration Key Laboratory of Silviculture in Downstream Areas of The Yellow River, College of Forestry, Shandong Agricultural University, Tai’an, Shandong, China
- Mountain Tai Forest Ecosystem Research Station of State Forestry and Grassland Administration, College of Forestry, Shandong Agricultural University, Tai’an, Shandong, China
| | - Junyi Ding
- State Forestry and Grassland Administration Key Laboratory of Silviculture in Downstream Areas of The Yellow River, College of Forestry, Shandong Agricultural University, Tai’an, Shandong, China
- Mountain Tai Forest Ecosystem Research Station of State Forestry and Grassland Administration, College of Forestry, Shandong Agricultural University, Tai’an, Shandong, China
| | - Norbert Holstein
- Department of Life Sciences, The Natural History Museum, London, United Kingdom
| | - Nian Wang
- State Forestry and Grassland Administration Key Laboratory of Silviculture in Downstream Areas of The Yellow River, College of Forestry, Shandong Agricultural University, Tai’an, Shandong, China
- Mountain Tai Forest Ecosystem Research Station of State Forestry and Grassland Administration, College of Forestry, Shandong Agricultural University, Tai’an, Shandong, China
| |
Collapse
|
4
|
Wang L, Ding J, Borrell JS, Cheek M, McAllister HA, Wang F, Liu L, Zhang H, Zhang Q, Wang Y, Wang N. Molecular and morphological analyses clarify species delimitation in section Costatae and reveal Betula buggsii sp. nov. (sect. Costatae, Betulaceae) in China. ANNALS OF BOTANY 2022; 129:415-428. [PMID: 35018419 PMCID: PMC8944703 DOI: 10.1093/aob/mcac001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Accepted: 01/05/2022] [Indexed: 06/14/2023]
Abstract
BACKGROUND AND AIMS Delineating closely related and morphologically similar species is difficult. Here, we integrate morphology, genetics, ploidy and geography to resolve species and subspecies boundaries in four trees of section Costatae (genus Betula): Betula ashburneri, B. costata, B. ermanii and B. utilis, as well as multiple subspecies and polyploid races. METHODS We genotyped 371 individuals (20-133 per species) from 51 populations at 15 microsatellite markers, as well as a subset of individuals, using restriction-site associated DNA sequencing and nuclear internal transcribed spacers. We determined the ploidy level of eight individuals using flow cytometry and characterized leaf variation for a subset of 109 individuals by morphometric analysis. KEY RESULTS Integration of multiple lines of evidence suggested a series of revisions to the taxonomy of section Costatae. Betula costata and B. ermanii were found to be valid. Molecular and leaf morphology analyses revealed little differentiation between diploid B. albosinensis and some samples of B. utilis ssp. utilis. By contrast, other B. utilis ssp. utilis samples and ssp. albosinensis formed a morphological continuum but differed based on genetics. Specifically, B. utilis ssp. albosinensis was divided into two groups with group I genetically similar to B. utilis ssp. utilis and group II, a distinct cluster, proposed as the new diploid species Betula buggsii sp. nov. Phylogenomic analysis based on 2285 620 single nucleotide polymorphisms identified a well-supported monophyletic clade of B. buggsii. Morphologically, B. buggsii is characterized by elongated lenticels and a distinct pattern of bark peeling and may be geographically restricted to the Qinling-Daba Mountains. CONCLUSIONS Our integrated approach identifies six taxa within section Costatae: B. ashburneri, B. buggsii, B. costata, B. utilis ssp. utilis, B. utilis ssp. albosinensis and B. ermanii. Our research demonstrates the value of an integrative approach using morphological, geographical, genetic and ploidy-level data for species delineation.
Collapse
Affiliation(s)
| | | | | | | | - Hugh A McAllister
- School of Life Sciences, Biosciences Building, University of Liverpool, Crown Street, Liverpool, UK
| | - Feifei Wang
- State Forestry and Grassland Administration Key Laboratory of Silviculture in Downstream Areas of the Yellow River, College of Forestry, Shandong Agricultural University, Tai’an, China
- Mountain Tai Forest Ecosystem Research Station of State Forestry and Grassland Administration, College of Forestry, Shandong Agricultural University, Tai’an, China
| | - Lu Liu
- State Forestry and Grassland Administration Key Laboratory of Silviculture in Downstream Areas of the Yellow River, College of Forestry, Shandong Agricultural University, Tai’an, China
- Mountain Tai Forest Ecosystem Research Station of State Forestry and Grassland Administration, College of Forestry, Shandong Agricultural University, Tai’an, China
| | - Huayu Zhang
- State Forestry and Grassland Administration Key Laboratory of Silviculture in Downstream Areas of the Yellow River, College of Forestry, Shandong Agricultural University, Tai’an, China
- Mountain Tai Forest Ecosystem Research Station of State Forestry and Grassland Administration, College of Forestry, Shandong Agricultural University, Tai’an, China
| | - Qiufeng Zhang
- State Forestry and Grassland Administration Key Laboratory of Silviculture in Downstream Areas of the Yellow River, College of Forestry, Shandong Agricultural University, Tai’an, China
- Mountain Tai Forest Ecosystem Research Station of State Forestry and Grassland Administration, College of Forestry, Shandong Agricultural University, Tai’an, China
| | - Yiming Wang
- State Forestry and Grassland Administration Key Laboratory of Silviculture in Downstream Areas of the Yellow River, College of Forestry, Shandong Agricultural University, Tai’an, China
- Mountain Tai Forest Ecosystem Research Station of State Forestry and Grassland Administration, College of Forestry, Shandong Agricultural University, Tai’an, China
| | | |
Collapse
|
5
|
Li Y, Zhang X, Wang L, Sork VL, Mao L, Fang Y. Influence of Pliocene and Pleistocene climates on hybridization patterns between two closely related oak species in China. ANNALS OF BOTANY 2022; 129:231-245. [PMID: 34893791 PMCID: PMC8796672 DOI: 10.1093/aob/mcab140] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 10/31/2021] [Accepted: 11/26/2021] [Indexed: 06/14/2023]
Abstract
BACKGROUND AND AIMS Contemporary patterns of genetic admixture reflect imprints of both ancient and recent gene flow, which can provide us with valuable information on hybridization history in response to palaeoclimate change. Here, we examine the relationships between present admixture patterns and past climatic niche suitability of two East Asian Cerris oaks (Quercus acutissima and Q. chenii) to test the hypothesis that the mid-Pliocene warm climate promoted while the Pleistocene cool climate limited hybridization among local closely related taxa. METHODS We analyse genetic variation at seven nuclear microsatellites (1111 individuals) and three chloroplast intergenic spacers (576 individuals) to determine the present admixture pattern and ancient hybridization history. We apply an information-theoretic model selection approach to explore the associations of genetic admixture degree with past climatic niche suitability at multiple spatial scales. KEY RESULTS More than 70 % of the hybrids determined by Bayesian clustering analysis and more than 90 % of the individuals with locally shared chloroplast haplotypes are concentrated within a mid-Pliocene contact zone between ~30°N and 35°N. Climatic niche suitabilities for Q. chenii during the mid-Pliocene Warm Period [mPWP, ~3.264-3.025 million years ago (mya)] and during the Last Glacial Maximum (LGM, ~0.022 mya) best explain the admixture patterns across all Q. acutissima populations and across those within the ancient contact zone, respectively. CONCLUSIONS Our results highlight that palaeoclimate change shapes present admixture patterns by influencing the extent of historical range overlap. Specifically, the mid-Pliocene warm climate promoted ancient contact, allowing widespread hybridization throughout central China. In contrast, the Pleistocene cool climate caused the local extinction of Q. chenii, reducing the probability of interspecific gene flow in most areas except those sites having a high level of ecological stability.
Collapse
Affiliation(s)
- Yao Li
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Biology and the Environment, Key Laboratory of State Forestry and Grassland Administration on Subtropical Forest Biodiversity Conservation, Nanjing Forestry University, Nanjing, Jiangsu 210037, China
- Laboratory of Biodiversity and Conservation, College of Biology and the Environment, Nanjing Forestry University, Nanjing, Jiangsu 210037, China
| | - Xingwang Zhang
- School of Life Sciences, Huaibei Normal University, Huaibei, Anhui 235000, China
| | - Lu Wang
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Biology and the Environment, Key Laboratory of State Forestry and Grassland Administration on Subtropical Forest Biodiversity Conservation, Nanjing Forestry University, Nanjing, Jiangsu 210037, China
| | - Victoria L Sork
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA 90095-7239, USA
- Institute of the Environment and Sustainability, University of California, Los Angeles, CA 90095-1496, USA
| | - Lingfeng Mao
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Biology and the Environment, Key Laboratory of State Forestry and Grassland Administration on Subtropical Forest Biodiversity Conservation, Nanjing Forestry University, Nanjing, Jiangsu 210037, China
- Laboratory of Biodiversity and Conservation, College of Biology and the Environment, Nanjing Forestry University, Nanjing, Jiangsu 210037, China
| | - Yanming Fang
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Biology and the Environment, Key Laboratory of State Forestry and Grassland Administration on Subtropical Forest Biodiversity Conservation, Nanjing Forestry University, Nanjing, Jiangsu 210037, China
| |
Collapse
|
6
|
Tarieiev AS, Gailing O, Krutovsky KV. ITS secondary structure reconstruction to resolve taxonomy and phylogeny of the Betula L. genus. PeerJ 2021; 9:e10889. [PMID: 33828907 PMCID: PMC7996101 DOI: 10.7717/peerj.10889] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 01/12/2021] [Indexed: 01/31/2023] Open
Abstract
The taxonomy and phylogeny of the Betula L. genus remain unresolved and are very difficult to assess due to several factors, especially because of frequent hybridization among different species. In the current study, we used nucleotide sequences of two internal transcribed spacer regions (ITS1 and ITS2), which are commonly used as phylogenetic markers. In addition to their nucleotide variation we reconstructed their secondary structure and used it to resolve phylogenetic relationships of some birch species. We explored whether consideration of secondary structure in phylogenetic analyses based on neighbor-joining, maximum parsimony, maximum likelihood, and Bayesian inference methods would help us obtain more solid support of the reconstructed phylogenetic trees. The results were not unambiguous. There were only a few clades with higher support when secondary structure was included into analysis. The phylogenetic trees generated using different methods were mostly in agreement with each other. However, the resolving power of these markers is still insufficient to reliably discriminate some closely related species. To achieve this aim more reliably there is a need for application of modern genomic approaches in combination with traditional ones.
Collapse
Affiliation(s)
- Andrii S. Tarieiev
- Department of Forest Genetics and Forest Tree Breeding, Georg-August University of Göttingen, Göttingen, Germany
| | - Oliver Gailing
- Department of Forest Genetics and Forest Tree Breeding, Georg-August University of Göttingen, Göttingen, Germany
- Center for Integrated Breeding Research, Georg-August University of Göttingen, Göttingen, Germany
| | - Konstantin V. Krutovsky
- Department of Forest Genetics and Forest Tree Breeding, Georg-August University of Göttingen, Göttingen, Germany
- Center for Integrated Breeding Research, Georg-August University of Göttingen, Göttingen, Germany
- Laboratory of Forest Genomics, Genome Research and Education Center, Institute of Fundamental Biology and Biotechnology, Siberian Federal University, Krasnoyarsk, Russia
- Laboratory of Population Genetics, N.I. Vavilov Institute of General Genetics, Russian Academy of Sciences, Moscow, Russia
- Department of Ecosystem Science and Management, Texas A&M University, College Station, TX, United States of America
| |
Collapse
|
7
|
Meucci S, Schulte L, Zimmermann HH, Stoof‐Leichsenring KR, Epp L, Bronken Eidesen P, Herzschuh U. Holocene chloroplast genetic variation of shrubs ( Alnus alnobetula, Betula nana, Salix sp.) at the siberian tundra-taiga ecotone inferred from modern chloroplast genome assembly and sedimentary ancient DNA analyses. Ecol Evol 2021; 11:2173-2193. [PMID: 33717447 PMCID: PMC7920767 DOI: 10.1002/ece3.7183] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 12/07/2020] [Accepted: 12/09/2020] [Indexed: 12/11/2022] Open
Abstract
Climate warming alters plant composition and population dynamics of arctic ecosystems. In particular, an increase in relative abundance and cover of deciduous shrub species (shrubification) has been recorded. We inferred genetic variation of common shrub species (Alnus alnobetula, Betula nana, Salix sp.) through time. Chloroplast genomes were assembled from modern plants (n = 15) from the Siberian forest-tundra ecotone. Sedimentary ancient DNA (sedaDNA; n = 4) was retrieved from a lake on the southern Taymyr Peninsula and analyzed by metagenomics shotgun sequencing and a hybridization capture approach. For A. alnobetula, analyses of modern DNA showed low intraspecies genetic variability and a clear geographical structure in haplotype distribution. In contrast, B. nana showed high intraspecies genetic diversity and weak geographical structure. Analyses of sedaDNA revealed a decreasing relative abundance of Alnus since 5,400 cal yr BP, whereas Betula and Salix increased. A comparison between genetic variations identified in modern DNA and sedaDNA showed that Alnus variants were maintained over the last 6,700 years in the Taymyr region. In accordance with modern individuals, the variants retrieved from Betula and Salix sedaDNA showed higher genetic diversity. The success of the hybridization capture in retrieving diverged sequences demonstrates the high potential for future studies of plant biodiversity as well as specific genetic variation on ancient DNA from lake sediments. Overall, our results suggest that shrubification has species-specific trajectories. The low genetic diversity in A. alnobetula suggests a local population recruitment and growth response of the already present communities, whereas the higher genetic variability and lack of geographical structure in B. nana may indicate a recruitment from different populations due to more efficient seed dispersal, increasing the genetic connectivity over long distances.
Collapse
Affiliation(s)
- Stefano Meucci
- Polar Terrestrial Environmental Systems Research GroupAlfred Wegener Institute Helmholtz Centre for Polar and Marine ResearchPotsdamGermany
- Institute of Biochemistry and BiologyUniversity of PotsdamPotsdamGermany
| | - Luise Schulte
- Polar Terrestrial Environmental Systems Research GroupAlfred Wegener Institute Helmholtz Centre for Polar and Marine ResearchPotsdamGermany
- Institute of Biochemistry and BiologyUniversity of PotsdamPotsdamGermany
| | - Heike H. Zimmermann
- Polar Terrestrial Environmental Systems Research GroupAlfred Wegener Institute Helmholtz Centre for Polar and Marine ResearchPotsdamGermany
| | - Kathleen R. Stoof‐Leichsenring
- Polar Terrestrial Environmental Systems Research GroupAlfred Wegener Institute Helmholtz Centre for Polar and Marine ResearchPotsdamGermany
| | - Laura Epp
- Department of BiologyUniversity of KonstanzKonstanzGermany
| | | | - Ulrike Herzschuh
- Polar Terrestrial Environmental Systems Research GroupAlfred Wegener Institute Helmholtz Centre for Polar and Marine ResearchPotsdamGermany
- Institute of Biochemistry and BiologyUniversity of PotsdamPotsdamGermany
- Institute of Environmental Sciences and GeographyUniversity of PotsdamPotsdamGermany
| |
Collapse
|
8
|
Wang N, Kelly LJ, McAllister HA, Zohren J, Buggs RJA. Resolving phylogeny and polyploid parentage using genus-wide genome-wide sequence data from birch trees. Mol Phylogenet Evol 2021; 160:107126. [PMID: 33647400 DOI: 10.1016/j.ympev.2021.107126] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 02/15/2021] [Accepted: 02/22/2021] [Indexed: 01/04/2023]
Abstract
Numerous plant genera have a history including frequent hybridisation and polyploidisation (allopolyploidisation), which means that their phylogeny is a network of reticulate evolution that cannot be accurately depicted as a bifurcating tree with a single tip per species. The genus Betula, which contains many ecologically important tree species, is a case in point. We generated genome-wide sequence reads for 27 diploid and 36 polyploid Betula species or subspecies using restriction site associated DNA (RAD) sequences. These reads were assembled into contigs with a mean length of 675 bp. We reconstructed the evolutionary relationships among diploid Betula species using both supermatrix (concatenation) and species tree methods. We identified the closest diploid relatives of the polyploids according to the relative rates at which reads from polyploids mapped to contigs from different diploid species within a concatenated reference sequence. By mapping reads from allopolyploids to their different putative diploid relatives we assembled contigs from the putative sub-genomes of allopolyploid taxa. We used these to build new phylogenies that included allopolyploid sub-genomes as separate tips. This approach yielded a highly evidenced phylogenetic hypothesis for the genus Betula, including the complex reticulate origins of the majority of its polyploid taxa. Our phylogeny divides the genus into two well supported clades, which, interestingly, differ in their seed-wing morphology. We therefore propose to split Betula into two subgenera.
Collapse
Affiliation(s)
- Nian Wang
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK; State Forestry and Grassland Administration Key Laboratory of Silviculture in Downstream Areas of the Yellow River, College of Forestry, Shandong Agricultural University, Tai'an 271018, China
| | - Laura J Kelly
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK; Royal Botanic Gardens Kew, Richmond, Surrey TW9 3AB, UK
| | - Hugh A McAllister
- Institute of Integrative Biology, Biosciences Building, University of Liverpool, Crown Street, Liverpool L69 7ZB, UK
| | - Jasmin Zohren
- Sex Chromosome Biology Lab, the Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Richard J A Buggs
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK; Royal Botanic Gardens Kew, Richmond, Surrey TW9 3AB, UK.
| |
Collapse
|
9
|
Borrell JS, Zohren J, Nichols RA, Buggs RJA. Genomic assessment of local adaptation in dwarf birch to inform assisted gene flow. Evol Appl 2020; 13:161-175. [PMID: 31892950 PMCID: PMC6935589 DOI: 10.1111/eva.12883] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 10/09/2019] [Accepted: 10/10/2019] [Indexed: 12/26/2022] Open
Abstract
When populations of a rare species are small, isolated and declining under climate change, some populations may become locally maladapted. Detecting this maladaptation may allow effective rapid conservation interventions, even if based on incomplete knowledge. Population maladaptation may be estimated by finding genome-environment associations (GEA) between allele frequencies and environmental variables across a local species range, and identifying populations whose allele frequencies do not fit with these trends. We can then design assisted gene flow strategies for maladapted populations, to adjust their allele frequencies, entailing lower levels of intervention than with undirected conservation action. Here, we investigate this strategy in Scottish populations of the montane plant dwarf birch (Betula nana). In genome-wide restriction site-associated single nucleotide polymorphism (SNP) data, we found 267 significant associations between SNP loci and environmental variables. We ranked populations by maladaptation estimated using allele frequency deviation from the general trends at these loci; this gave a different prioritization for conservation action than the Shapely Index, which seeks to preserve rare neutral variation. Populations estimated to be maladapted in their allele frequencies at loci associated with annual mean temperature were found to have reduced catkin production. Using an environmental niche modelling (ENM) approach, we found annual mean temperature (35%), and mean diurnal range (15%), to be important predictors of the dwarf birch distribution. Intriguingly, there was a significant correlation between the number of loci associated with each environmental variable in the GEA and the importance of that variable in the ENM. Together, these results suggest that the same environmental variables determine both adaptive genetic variation and species range in Scottish dwarf birch. We suggest an assisted gene flow strategy that aims to maximize the local adaptation of dwarf birch populations under climate change by matching allele frequencies to current and future environments.
Collapse
Affiliation(s)
| | - Jasmin Zohren
- Sex Chromosome Biology LabThe Francis Crick InstituteLondonUK
| | - Richard A. Nichols
- School of Biological and Chemical SciencesQueen Mary University of LondonLondonUK
| | - Richard J. A. Buggs
- Jodrell LaboratoryRoyal Botanic Gardens, KewSurreyUK
- School of Biological and Chemical SciencesQueen Mary University of LondonLondonUK
| |
Collapse
|
10
|
Borrell JS, Al Issaey G, Lupton DA, Starnes T, Al Hinai A, Al Hatmi S, Senior RA, Wilkinson T, Milborrow JLH, Stokes-Rees A, Patzelt A. Islands in the desert: environmental distribution modelling of endemic flora reveals the extent of Pleistocene tropical relict vegetation in southern Arabia. ANNALS OF BOTANY 2019; 124:411-422. [PMID: 31418009 PMCID: PMC6798844 DOI: 10.1093/aob/mcz085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2019] [Accepted: 05/13/2019] [Indexed: 06/10/2023]
Abstract
BACKGROUND AND AIMS Southern Arabia is a global biodiversity hotspot with a high proportion of endemic desert-adapted plants. Here we examine evidence for a Pleistocene climate refugium in the southern Central Desert of Oman, and its role in driving biogeographical patterns of endemism. METHODS Distribution data for seven narrow-range endemic plants were collected systematically across 195 quadrats, together with incidental and historic records. Important environmental variables relevant to arid coastal areas, including night-time fog and cloud cover, were developed for the study area. Environmental niche models using presence/absence data were built and tuned for each species, and spatial overlap was examined. KEY RESULTS A region of the Jiddat Al Arkad reported independent high model suitability for all species. Examination of environmental data across southern Oman indicates that the Jiddat Al Arkad displays a regionally unique climate with higher intra-annual stability, due in part to the influence of the southern monsoon. Despite this, the relative importance of environmental variables was highly differentiated among species, suggesting that characteristic variables such as coastal fog are not major cross-species predictors at this scale. CONCLUSIONS The co-occurrence of a high number of endemic study species within a narrow monsoon-influenced region is indicative of a refugium with low climate change velocity. Combined with climate analysis, our findings provide strong evidence for a southern Arabian Pleistocene refugium in Oman's Central Desert. We suggest that this refugium has acted as an isolated temperate and mesic island in the desert, resulting in the evolution of these narrow-range endemic flora. Based on the composition of species, this system may represent the northernmost remnant of a continuous belt of mesic vegetation formerly ranging from Africa to Asia, with close links to the flora of East Africa. This has significant implications for future conservation of endemic plants in an arid biodiversity hotspot.
Collapse
Affiliation(s)
- James S Borrell
- Jodrell Laboratory, Royal Botanic Gardens, Kew, Richmond, Surrey, UK
| | | | | | - Thomas Starnes
- RSPB Centre for Conservation Science, Royal Society for the Protection of Birds, The Lodge, Sandy, Bedfordshire, UK
| | | | | | - Rebecca A Senior
- Department of Animal and Plant Sciences, Alfred Denny Building, University of Sheffield, Western Bank, Sheffield, UK
| | - Tim Wilkinson
- Jodrell Laboratory, Royal Botanic Gardens, Kew, Richmond, Surrey, UK
| | | | | | | |
Collapse
|
11
|
Hu YN, Zhao L, Buggs RJA, Zhang XM, Li J, Wang N. Population structure of Betula albosinensis and Betula platyphylla: evidence for hybridization and a cryptic lineage. ANNALS OF BOTANY 2019; 123:1179-1189. [PMID: 30916314 PMCID: PMC6612935 DOI: 10.1093/aob/mcz024] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Revised: 01/15/2019] [Accepted: 02/05/2019] [Indexed: 05/20/2023]
Abstract
BACKGROUND AND AIMS Differences in local abundance and ploidy level are predicted to impact the direction of introgression between species. Here, we tested these hypotheses on populations of Betula albosinensis (red birch) and Betula platyphylla (white birch) which were thought to differ in ploidy level, the former being tetraploid and the latter diploid. METHODS We sampled 391 birch individuals from nine localities in China, and classified them into species based on leaf morphology. Twelve nuclear microsatellite markers were genotyped in each sample, and analysed using principal coordinates analysis and STRUCTURE software. We compared the effects of two different methods of scoring polyploid genotypes on population genetic analyses. We analysed the effect of ploidy, local species abundance and latitude on levels of introgression between the species. KEY RESULTS Leaf morphology divided our samples into red and white birch, but genetic analyses unexpectedly revealed two groups within red birch, one of which was tetraploid, as expected, but the other of which appeared to have diploid microsatellite genotypes. Five individuals were identified as early-generation hybrids or backcrosses between white birch and red birch and five were identified between red birch and 'diploid' red birch. Cline analysis showed that levels of admixture were not significantly correlated with latitude. Estimated genetic differentiation among species was not significantly different between determined tetraploid and undetermined tetraploid genotypes. CONCLUSIONS Limited hybridization and gene flow have occurred between red birch and white birch. Relative species abundance and ploidy level do not impact the direction of introgression between them, as genetic admixture is roughly symmetrical. We unexpectedly found populations of apparently diploid red birch and this taxon may be a progenitor of allotetraploid red birch populations. Incomplete lineage sorting may explain patterns of genetic admixture between apparently diploid and allotetraploid red birch.
Collapse
Affiliation(s)
- Ya-Nan Hu
- College of Forestry, Shandong Agricultural University, Tai’an city, Shandong province, China
| | - Lei Zhao
- Beijing Key Laboratory of Biodiversity and Organic Farming, College of Resources and Environmental Sciences, China Agricultural University, Beijing, China
| | - Richard J A Buggs
- Jodrell Laboratory, Royal Botanic Gardens, Kew, Richmond, Surrey, UK
- School of Biological and Chemical Sciences, Queen Mary University of London, London, UK
| | - Xue-Min Zhang
- Mulan-Weichang National Forestry Administration, Chengde, China
| | - Jun Li
- Mulan-Weichang National Forestry Administration, Chengde, China
| | - Nian Wang
- College of Forestry, Shandong Agricultural University, Tai’an city, Shandong province, China
| |
Collapse
|
12
|
Borrell JS, Wang N, Nichols RA, Buggs RJA. Genetic diversity maintained among fragmented populations of a tree undergoing range contraction. Heredity (Edinb) 2018; 121:304-318. [PMID: 30111882 PMCID: PMC6134035 DOI: 10.1038/s41437-018-0132-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 07/06/2018] [Accepted: 07/07/2018] [Indexed: 11/09/2022] Open
Abstract
Dwarf birch (Betula nana) has a widespread boreal distribution but has declined significantly in Britain where populations are now highly fragmented. We analyzed the genetic diversity of these fragmented populations using markers that differ in mutation rate: conventional microsatellites markers (PCR-SSRs), RADseq generated transition and transversion SNPs (RAD-SNPs), and microsatellite markers mined from RADseq reads (RAD-SSRs). We estimated the current population sizes by census and indirectly, from the linkage-disequilibrium found in the genetic surveys. The two types of estimate were highly correlated. Overall, we found genetic diversity to be only slightly lower in Britain than across a comparable area in Scandinavia where populations are large and continuous. While the ensemble of British fragments maintain diversity levels close to Scandinavian populations, individually they have drifted apart and lost diversity; particularly the smaller populations. An ABC analysis, based on coalescent models, favors demographic scenarios in which Britain maintained high levels of genetic diversity through post-glacial re-colonization. This diversity has subsequently been partitioned into population fragments that have recently lost diversity at a rate corresponding to the current population-size estimates. We conclude that the British population fragments retain sufficient genetic resources to be the basis of conservation and re-planting programmes. Use of markers with different mutation rates gives us greater confidence and insight than one marker set could have alone, and we suggest that RAD-SSRs are particularly useful as high mutation-rate marker set with a well-specified ascertainment bias, which are widely available yet often neglected in existing RAD datasets.
Collapse
Affiliation(s)
- James S Borrell
- Jodrell Laboratory, Royal Botanic Gardens, Kew, Richmond, Surrey, TW9 3DS, UK
| | - Nian Wang
- School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, UK
- College of Forestry, Shandong Agricultural University, Tai'an city, 271018, Shandong Province, China
| | - Richard A Nichols
- School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, UK
| | - Richard J A Buggs
- Jodrell Laboratory, Royal Botanic Gardens, Kew, Richmond, Surrey, TW9 3DS, UK.
- School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, UK.
| |
Collapse
|
13
|
Wielstra B, Burke T, Butlin RK, Avcı A, Üzüm N, Bozkurt E, Olgun K, Arntzen JW. A genomic footprint of hybrid zone movement in crested newts. Evol Lett 2017; 1:93-101. [PMID: 30283642 PMCID: PMC6121819 DOI: 10.1002/evl3.9] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Accepted: 04/04/2017] [Indexed: 01/18/2023] Open
Abstract
Speciation typically involves a stage in which species can still exchange genetic material. Interspecific gene flow is facilitated by the hybrid zones that such species establish upon secondary contact. If one member of a hybridizing species pair displaces the other, their hybrid zone would move across the landscape. Although theory predicts that moving hybrid zones quickly stagnate, hybrid zones tracked over one or a few decades do not always follow such a limitation. This suggests that hybrid zones have the potential to traverse considerable distances over extended periods of time. When hybrid zones move, introgression is predicted to result in biased gene flow of selectively neutral alleles, from the receding species into the advancing species. We test for such a genomic footprint of hybrid zone movement in a pair of crested newt species (genus Triturus) for which we have a priori support for westward hybrid zone movement. We perform a multilocus phylogeographical survey and conduct Bayesian clustering analysis, estimation of ancestry and heterozygosity, and geographical cline analysis. In a 600 km wide area east of the present day hybrid zone a genomic footprint constitutes empirical evidence consistent with westward hybrid zone movement. The crested newt case suggests that hybrid zone movement can occur over an extensive span of time and space. Inferring hybrid zone movement provides fundamental insight into historical biogeography and the speciation process, and we anticipate that hybrid zones will prove to be far more mobile than currently appreciated.
Collapse
Affiliation(s)
- Ben Wielstra
- Department of Animal and Plant Sciences University of Sheffield S10 2TN Sheffield United Kingdom.,Naturalis Biodiversity Center 2300 RA Leiden The Netherlands.,Department of Ecology and Evolutionary Biology University of California Los Angeles California 90095
| | - Terry Burke
- Department of Animal and Plant Sciences University of Sheffield S10 2TN Sheffield United Kingdom
| | - Roger K Butlin
- Department of Animal and Plant Sciences University of Sheffield S10 2TN Sheffield United Kingdom.,Department of Marine Sciences University of Gothenburg S 405 30 Gothenburg Sweden
| | - Aziz Avcı
- Department of Biology, Faculty of Arts and Sciences Adnan Menderes University 09010 Aydın Turkey
| | - Nazan Üzüm
- Department of Biology, Faculty of Arts and Sciences Adnan Menderes University 09010 Aydın Turkey
| | - Emin Bozkurt
- Department of Biology, Faculty of Arts and Sciences Adnan Menderes University 09010 Aydın Turkey
| | - Kurtuluş Olgun
- Department of Biology, Faculty of Arts and Sciences Adnan Menderes University 09010 Aydın Turkey
| | - Jan W Arntzen
- Naturalis Biodiversity Center 2300 RA Leiden The Netherlands
| |
Collapse
|
14
|
Tsuda Y, Semerikov V, Sebastiani F, Vendramin GG, Lascoux M. Multispecies genetic structure and hybridization in theBetulagenus across Eurasia. Mol Ecol 2016; 26:589-605. [DOI: 10.1111/mec.13885] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 09/19/2016] [Indexed: 01/18/2023]
Affiliation(s)
- Yoshiaki Tsuda
- Department of Ecology and Genetics; Evolutionary Biology Centre; Science for Life Laboratory; Uppsala University; Norbyvägen 18D 75236 Uppsala Sweden
- Institute of Biosciences and Bioresources; Division of Florence; National Research Council; Via Madonna del Piano 10 50019 Sesto Fiorentino (Firenze) Italy
| | - Vladimir Semerikov
- Institute of Plant and Animal Ecology; Ural Branch of Russian Academy of Science; Ekaterinburg 620144 Russia
| | - Federico Sebastiani
- Institute of Biosciences and Bioresources; Division of Florence; National Research Council; Via Madonna del Piano 10 50019 Sesto Fiorentino (Firenze) Italy
| | - Giovanni Giuseppe Vendramin
- Institute of Biosciences and Bioresources; Division of Florence; National Research Council; Via Madonna del Piano 10 50019 Sesto Fiorentino (Firenze) Italy
| | - Martin Lascoux
- Department of Ecology and Genetics; Evolutionary Biology Centre; Science for Life Laboratory; Uppsala University; Norbyvägen 18D 75236 Uppsala Sweden
| |
Collapse
|
15
|
Kozlov MV, Skoracka A, Zverev V, Lewandowski M, Zvereva EL. Two Birch Species Demonstrate Opposite Latitudinal Patterns in Infestation by Gall-Making Mites in Northern Europe. PLoS One 2016; 11:e0166641. [PMID: 27835702 PMCID: PMC5105990 DOI: 10.1371/journal.pone.0166641] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Accepted: 11/01/2016] [Indexed: 11/19/2022] Open
Abstract
Latitudinal patterns in herbivory, i.e. variations in plant losses to animals with latitude, are generally explained by temperature gradients. However, earlier studies suggest that geographical variation in abundance and diversity of gall-makers may be driven by precipitation rather than by temperature. To test the above hypothesis, we examined communities of eriophyoid mites (Acari: Eriophyoidea) on leaves of Betula pendula and B. pubescens in boreal forests in Northern Europe. We sampled ten sites for each of five latitudinal gradients from 2008-2011, counted galls of six morphological types and identified mites extracted from these galls. DNA analysis revealed cryptic species within two of six morphologically defined mite species, and these cryptic species induced different types of galls. When data from all types of galls and from two birch species were pooled, the percentage of galled leaves did not change with latitude. However, we discovered pronounced variation in latitudinal changes between birch species. Infestation by eriophyoid mites increased towards the north in B. pendula and decreased in B. pubescens, while diversity of galls decreased towards the north in B. pendula and did not change in B. pubescens. The percentage of galled leaves did not differ among geographical gradients and study years, but was 20% lower in late summer relative to early summer, indicating premature abscission of infested leaves. Our data suggest that precipitation has little effect on abundance and diversity of eriophyoid mites, and that climate warming may impose opposite effects on infestation of two birch species by galling mites, favouring B. pendula near the northern tree limit.
Collapse
Affiliation(s)
- Mikhail V. Kozlov
- Section of Ecology, Department of Biology, University of Turku, Turku, Finland
- * E-mail:
| | - Anna Skoracka
- Population Ecology Laboratory, Faculty of Biology, Adam Mickiewicz University, Poznan, Poland
| | - Vitali Zverev
- Section of Ecology, Department of Biology, University of Turku, Turku, Finland
| | - Mariusz Lewandowski
- Department of Applied Entomology, Faculty of Agriculture, Biotechnology and Landscape Architecture, Warsaw University of Life Sciences—SGGW, Warsaw, Poland
| | - Elena L. Zvereva
- Section of Ecology, Department of Biology, University of Turku, Turku, Finland
| |
Collapse
|
16
|
Zohren J, Wang N, Kardailsky I, Borrell JS, Joecker A, Nichols RA, Buggs RJA. Unidirectional diploid-tetraploid introgression among British birch trees with shifting ranges shown by restriction site-associated markers. Mol Ecol 2016; 25:2413-26. [PMID: 27065091 PMCID: PMC4999052 DOI: 10.1111/mec.13644] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Revised: 04/05/2016] [Accepted: 04/08/2016] [Indexed: 01/02/2023]
Abstract
Hybridization may lead to introgression of genes among species. Introgression may be bidirectional or unidirectional, depending on factors such as the demography of the hybridizing species, or the nature of reproductive barriers between them. Previous microsatellite studies suggested bidirectional introgression between diploid Betula nana (dwarf birch) and tetraploid B. pubescens (downy birch) and also between B. pubescens and diploid B. pendula (silver birch) in Britain. Here, we analyse introgression among these species using 51 237 variants in restriction site‐associated (RAD) markers in 194 individuals, called with allele dosages in the tetraploids. In contrast to the microsatellite study, we found unidirectional introgression into B. pubescens from both of the diploid species. This pattern fits better with the expected nature of the reproductive barrier between diploids and tetraploids. As in the microsatellite study, introgression into B. pubescens showed clear clines with increasing introgression from B. nana in the north and from B. pendula in the south. Unlike B. pendula alleles, introgression of B. nana alleles was found far from the current area of sympatry or allopatry between B. nana and B. pubescens. This pattern fits a shifting zone of hybridization due to Holocene reduction in the range of B. nana and expansion in the range of B. pubescens.
Collapse
Affiliation(s)
- Jasmin Zohren
- School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, UK
| | - Nian Wang
- School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, UK
| | - Igor Kardailsky
- QIAGEN Aarhus A/S, Silkeborgvej 2, Prismet, Aarhus C, 8000, Denmark
| | - James S Borrell
- School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, UK
| | - Anika Joecker
- QIAGEN Aarhus A/S, Silkeborgvej 2, Prismet, Aarhus C, 8000, Denmark
| | - Richard A Nichols
- School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, UK
| | - Richard J A Buggs
- School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, UK
| |
Collapse
|
17
|
Wang N, McAllister HA, Bartlett PR, Buggs RJA. Molecular phylogeny and genome size evolution of the genus Betula (Betulaceae). ANNALS OF BOTANY 2016; 117:1023-35. [PMID: 27072644 PMCID: PMC4866320 DOI: 10.1093/aob/mcw048] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Revised: 07/09/2015] [Accepted: 01/19/2016] [Indexed: 05/24/2023]
Abstract
BACKGROUND AND AIMS Betula L. (birch) is a genus of approx. 60 species, subspecies or varieties with a wide distribution in the northern hemisphere, of ecological and economic importance. A new classification of Betula has recently been proposed based on morphological characters. This classification differs somewhat from previously published molecular phylogenies, which may be due to factors such as convergent evolution, hybridization, incomplete taxon sampling or misidentification of samples. While chromosome counts have been made for many species, few have had their genome size measured. The aim of this study is to produce a new phylogenetic and genome size analysis of the genus. METHODS Internal transcribed spacer (ITS) regions of nuclear ribosomal DNA were sequenced for 76 Betula samples verified by taxonomic experts, representing approx. 60 taxa, of which approx. 24 taxa have not been included in previous phylogenetic analyses. A further 49 samples from other collections were also sequenced, and 108 ITS sequences were downloaded from GenBank. Phylogenetic trees were built for these sequences. The genome sizes of 103 accessions representing nearly all described species were estimated using flow cytometry. KEY RESULTS As expected for a gene tree of a genus where hybridization and allopolyploidy occur, the ITS tree shows clustering, but not resolved monophyly, for the morphological subgenera recently proposed. Most sections show some clustering, but species of the dwarf section Apterocaryon are unusually scattered. Betula corylifolia (subgenus Nipponobetula) unexpectedly clusters with species of subgenus Aspera Unexpected placements are also found for B. maximowicziana, B. bomiensis, B. nigra and B. grossa Biogeographical disjunctions were found within Betula between Europe and North America, and also disjunctions between North-east and South-west Asia. The 2C-values for Betula ranged from 0·88 to 5·33 pg, and polyploids are scattered widely throughout the ITS phylogeny. Species with large genomes tend to have narrow ranges. CONCLUSIONS Betula grossa may have formed via allopolyploidization between parents in subgenus Betula and subgenus Aspera. Betula bomiensis may also be a wide allopolyploid. Betula corylifolia may be a parental species of allopolyploids in the subsection Chinenses Placements of B. maximowicziana, B. michauxii and B. nigra need further investigation. This analysis, in line with previous studies, suggests that section Apterocaryon is not monophyletic and thus dwarfism has evolved repeatedly in different lineages of Betula Polyploidization has occurred many times independently in the evolution of Betula.
Collapse
Affiliation(s)
- Nian Wang
- School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK
| | - Hugh A McAllister
- Institute of Integrative Biology, Biosciences Building, University of Liverpool, Crown Street, Liverpool L69 7ZB, UK and
| | - Paul R Bartlett
- Stone Lane Gardens, Stone Farm, Chagford, Devon TQ13 8JU, UK
| | - Richard J A Buggs
- School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK,
| |
Collapse
|
18
|
Suarez-Gonzalez A, Hefer CA, Christe C, Corea O, Lexer C, Cronk QCB, Douglas CJ. Genomic and functional approaches reveal a case of adaptive introgression fromPopulus balsamifera(balsam poplar) inP. trichocarpa(black cottonwood). Mol Ecol 2016; 25:2427-42. [DOI: 10.1111/mec.13539] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Revised: 01/02/2016] [Accepted: 01/06/2016] [Indexed: 01/14/2023]
Affiliation(s)
| | - Charles A. Hefer
- Department of Botany; University of British Columbia; Vancouver BC V6T 1Z4 Canada
| | - Camille Christe
- Unit of Ecology & Evolution; Department of Biology; University of Fribourg; CH-1700 Fribourg Switzerland
| | - Oliver Corea
- Department of Biology and Centre for Forest Biology; University of Victoria; Victoria BC V8W 3N5 Canada
| | - Christian Lexer
- Unit of Ecology & Evolution; Department of Biology; University of Fribourg; CH-1700 Fribourg Switzerland
- Department of Botany and Biodiversity Research; University of Vienna; A-1030 Vienna Austria
| | - Quentin C. B. Cronk
- Department of Botany; University of British Columbia; Vancouver BC V6T 1Z4 Canada
| | - Carl J. Douglas
- Department of Botany; University of British Columbia; Vancouver BC V6T 1Z4 Canada
| |
Collapse
|
19
|
Eidesen PB, Alsos IG, Brochmann C. Comparative analyses of plastid and AFLP data suggest different colonization history and asymmetric hybridization betweenBetula pubescensandB. nana. Mol Ecol 2015; 24:3993-4009. [DOI: 10.1111/mec.13289] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Revised: 06/17/2015] [Accepted: 06/18/2015] [Indexed: 01/18/2023]
Affiliation(s)
| | | | - Christian Brochmann
- Natural History Museum; University of Oslo; PO Box 1172 Blindern NO-0318 Oslo Norway
| |
Collapse
|
20
|
Clark LV, Stewart JR, Nishiwaki A, Toma Y, Kjeldsen JB, Jørgensen U, Zhao H, Peng J, Yoo JH, Heo K, Yu CY, Yamada T, Sacks EJ. Genetic structure of Miscanthus sinensis and Miscanthus sacchariflorus in Japan indicates a gradient of bidirectional but asymmetric introgression. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:4213-25. [PMID: 25618143 PMCID: PMC4493777 DOI: 10.1093/jxb/eru511] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Unilateral introgression from diploids to tetraploids has been hypothesized to be an important evolutionary mechanism in plants. However, few examples have been definitively identified, perhaps because data of sufficient depth and breadth were difficult to obtain before the advent of affordable high-density genotyping. Throughout Japan, tetraploid Miscanthus sacchariflorus and diploid Miscanthus sinensis are common, and occasionally hybridize. In this study, 667 M. sinensis and 78 M. sacchariflorus genotypes from Japan were characterized using 20 704 SNPs and ten plastid microsatellites. Similarity of SNP genotypes between diploid and tetraploid M. sacchariflorus indicated that the tetraploids originated through autopolyploidy. Structure analysis indicated a gradient of introgression from diploid M. sinensis into tetraploid M. sacchariflorus throughout Japan; most tetraploids had some M. sinensis DNA. Among phenotypically M. sacchariflorus tetraploids, M. sinensis ancestry averaged 7% and ranged from 1-39%, with introgression greatest in southern Japan. Unexpectedly, rare (~1%) diploid M. sinensis individuals from northern Japan were found with 6-27% M. sacchariflorus ancestry. Population structure of M. sinensis in Japan included three groups, and was driven primarily by distance, and secondarily by geographic barriers such as mountains and straits. Miscanthus speciation is a complex and dynamic process. In contrast to limited introgression between diploid M. sacchariflorus and M. sinensis in northern China, selection for adaptation to a moderate maritime climate probably favoured cross-ploidy introgressants in southern Japan. These results will help guide the selection of Miscanthus accessions for the breeding of biomass cultivars.
Collapse
Affiliation(s)
- Lindsay V Clark
- Department of Crop Sciences, University of Illinois, Urbana-Champaign, Urbana, IL 61801, USA
| | - J Ryan Stewart
- Department of Plant and Wildlife Sciences, Brigham Young University, Provo, UT 84602, USA
| | - Aya Nishiwaki
- Field Science Center, Faculty of Agriculture, University of Miyazaki, Miyazaki, Miyazaki 889-2192, Japan
| | - Yo Toma
- Faculty of Agriculture, Ehime University, Matsuyama, Ehime 790-8566, Japan
| | | | - Uffe Jørgensen
- Department of Agroecology, Aarhus University, Tjele DK-8830, Denmark
| | - Hua Zhao
- College of Horticulture and Forestry Science, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Junhua Peng
- Science and Technology Center, China Seed Group Co. Ltd, Wuhan, Hubei 430040, China
| | - Ji Hye Yoo
- Kangwon National University, Chuncheon, Gangwon 200-701, South Korea
| | - Kweon Heo
- Kangwon National University, Chuncheon, Gangwon 200-701, South Korea
| | - Chang Yeon Yu
- Kangwon National University, Chuncheon, Gangwon 200-701, South Korea
| | - Toshihiko Yamada
- Field Science Center for Northern Biosphere, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan
| | - Erik J Sacks
- Department of Crop Sciences, University of Illinois, Urbana-Champaign, Urbana, IL 61801, USA
| |
Collapse
|
21
|
Wang N, Borrell JS, Buggs RJA. Is the Atkinson discriminant function a reliable method for distinguishing betweenBetula pendulaandB. pubescens(Betulaceae)? ACTA ACUST UNITED AC 2014. [DOI: 10.1179/2042349714y.0000000044] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
|
22
|
Wang N, Borrell JS, Bodles WJA, Kuttapitiya A, Nichols RA, Buggs RJA. Molecular footprints of the Holocene retreat of dwarf birch in Britain. Mol Ecol 2014; 23:2771-82. [PMID: 24762172 PMCID: PMC4237149 DOI: 10.1111/mec.12768] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Revised: 04/19/2014] [Accepted: 04/21/2014] [Indexed: 01/17/2023]
Abstract
Past reproductive interactions among incompletely isolated species may leave behind a trail of introgressed alleles, shedding light on historical range movements. Betula pubescens is a widespread native tetraploid tree species in Britain, occupying habitats intermediate to those of its native diploid relatives, B. pendula and B. nana. Genotyping 1134 trees from the three species at 12 microsatellite loci, we found evidence of introgression from both diploid species into B. pubescens, despite the ploidy difference. Surprisingly, introgression from B. nana, a dwarf species whose present range is highly restricted in northern, high-altitude peat bogs, was greater than introgression from B. pendula, which is morphologically similar to B. pubescens and has a substantially overlapping range. A cline of introgression from B. nana was found extending into B. pubescens populations far to the south of the current B. nana range. We suggest that this genetic pattern is a footprint of a historical decline and/or northwards shift in the range of B. nana populations due to climate warming in the Holocene. This is consistent with pollen records that show a broader, more southerly distribution of B. nana in the past. Ecological niche modelling predicts that B. nana is adapted to a larger range than it currently occupies, suggesting additional factors such as grazing and hybridization may have exacerbated its decline. We found very little introgression between B. nana and B. pendula, despite both being diploid, perhaps because their distributions in the past have rarely overlapped. Future conservation of B. nana may partly depend on minimization of hybridization with B. pubescens, and avoidance of planting B. pendula near B. nana populations.
Collapse
Affiliation(s)
- Nian Wang
- School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, UK
| | | | | | | | | | | |
Collapse
|