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Kiebacher T, Szövényi P. Morphological, genetic and ecological divergence in near-cryptic bryophyte species widespread in the Holarctic: the Dicranum acutifolium complex (Dicranales) revisited in the Alps. JOURNAL OF PLANT RESEARCH 2024; 137:561-574. [PMID: 38520483 PMCID: PMC11230997 DOI: 10.1007/s10265-024-01534-3] [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: 06/28/2023] [Accepted: 02/15/2024] [Indexed: 03/25/2024]
Abstract
There is mounting evidence that reproductively isolated, but morphologically weakly differentiated species (so-called cryptic species) represent a substantial part of biological diversity, especially in bryophytes. We assessed the evolutionary history and ecological differentiation of a species pair, Dicranum brevifolium and D. septentrionale, which have overlapping ranges in the Holarctic. Despite their morphological similarity, we found similar genetic differentiation as between morphologically well-differentiated Dicranum species. Moreover, we detected gene tree discordance between plastid and nuclear markers, but neither of the two datasets resolved the two as sister species. The signal in trnL-trnF better reflects the morphological and ecological affinities and indicates a close relationship while ITS sequence data resolved the two taxa as phylogenetically distantly related. The discordance is probably unrelated to the ecological differentiation of D. septentrionale to colonise subneutral to alkaline substrates (vs. acidic in D. brevifolium), because this ability is rare in the genus and shared with D. acutifolium. This taxon is the closest relative of D. septentrionale according to the trnL-trnF data and does not share the discordance in ITS. We furthermore demonstrate that beside D. acutifolium, both D. septentrionale and D. brevifolium occur in the Alps but D. brevifolium is most likely rarer. Based on morphological analyses including factor analysis for mixed data of 45 traits we suggest treating the latter two as near-cryptic species and we recommend verifying morphological determinations molecularly.
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Affiliation(s)
- Thomas Kiebacher
- Department of Botany, Stuttgart State Museum of Natural History, Rosenstein 1, 70191, Stuttgart, Germany.
- Department of Systematic and Evolutionary Botany, University of Zurich UZH, Zollikerstrasse 107, 8008, Zurich, Switzerland.
| | - Péter Szövényi
- Department of Systematic and Evolutionary Botany, University of Zurich UZH, Zollikerstrasse 107, 8008, Zurich, Switzerland
- Zurich-Basel Plant Science Center (PSC), ETH Zürich, Tannenstrasse 1, 8092, Zurich, Switzerland
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Piatkowski B, Weston DJ, Aguero B, Duffy A, Imwattana K, Healey AL, Schmutz J, Shaw AJ. Divergent selection and climate adaptation fuel genomic differentiation between sister species of Sphagnum (peat moss). ANNALS OF BOTANY 2023; 132:499-512. [PMID: 37478307 PMCID: PMC10666999 DOI: 10.1093/aob/mcad104] [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: 05/12/2023] [Accepted: 07/24/2023] [Indexed: 07/23/2023]
Abstract
BACKGROUND AND AIMS New plant species can evolve through the reinforcement of reproductive isolation via local adaptation along habitat gradients. Peat mosses (Sphagnaceae) are an emerging model system for the study of evolutionary genomics and have well-documented niche differentiation among species. Recent molecular studies have demonstrated that the globally distributed species Sphagnum magellanicum is a complex of morphologically cryptic lineages that are phylogenetically and ecologically distinct. Here, we describe the architecture of genomic differentiation between two sister species in this complex known from eastern North America: the northern S. diabolicum and the largely southern S. magniae. METHODS We sampled plant populations from across a latitudinal gradient in eastern North America and performed whole genome and restriction-site associated DNA sequencing. These sequencing data were then analyzed computationally. KEY RESULTS Using sliding-window population genetic analyses we find that differentiation is concentrated within 'islands' of the genome spanning up to 400 kb that are characterized by elevated genetic divergence, suppressed recombination, reduced nucleotide diversity and increased rates of non-synonymous substitution. Sequence variants that are significantly associated with genetic structure and bioclimatic variables occur within genes that have functional enrichment for biological processes including abiotic stress response, photoperiodism and hormone-mediated signalling. Demographic modelling demonstrates that these two species diverged no more than 225 000 generations ago with secondary contact occurring where their ranges overlap. CONCLUSIONS We suggest that this heterogeneity of genomic differentiation is a result of linked selection and reflects the role of local adaptation to contrasting climatic zones in driving speciation. This research provides insight into the process of speciation in a group of ecologically important plants and strengthens our predictive understanding of how plant populations will respond as Earth's climate rapidly changes.
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Affiliation(s)
- Bryan Piatkowski
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - David J Weston
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Blanka Aguero
- Department of Biology, Duke University, Durham, NC 27708, USA
| | - Aaron Duffy
- Department of Biology, Duke University, Durham, NC 27708, USA
| | - Karn Imwattana
- Department of Biology, Duke University, Durham, NC 27708, USA
| | - Adam L Healey
- Genome Sequencing Center, HudsonAlpha Institute for Biotechnology, Huntsville, AL 35806, USA
| | - Jeremy Schmutz
- Genome Sequencing Center, HudsonAlpha Institute for Biotechnology, Huntsville, AL 35806, USA
- Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - A Jonathan Shaw
- Department of Biology, Duke University, Durham, NC 27708, USA
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Giesen A, Blanckenhorn WU, Schäfer MA, Shimizu KK, Shimizu-Inatsugi R, Misof B, Podsiadlowski L, Niehuis O, Lischer HEL, Aeschbacher S, Kapun M. Geographic Variation in Genomic Signals of Admixture Between Two Closely Related European Sepsid Fly Species. Evol Biol 2023; 50:395-412. [PMID: 37854269 PMCID: PMC10579158 DOI: 10.1007/s11692-023-09612-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 07/28/2023] [Indexed: 10/20/2023]
Abstract
The extent of interspecific gene flow and its consequences for the initiation, maintenance, and breakdown of species barriers in natural systems remain poorly understood. Interspecific gene flow by hybridization may weaken adaptive divergence, but can be overcome by selection against hybrids, which may ultimately promote reinforcement. An informative step towards understanding the role of gene flow during speciation is to describe patterns of past gene flow among extant species. We investigate signals of admixture between allopatric and sympatric populations of the two closely related European dung fly species Sepsis cynipsea and S. neocynipsea (Diptera: Sepsidae). Based on microsatellite genotypes, we first inferred a baseline demographic history using Approximate Bayesian Computation. We then used genomic data from pooled DNA of natural and laboratory populations to test for past interspecific gene flow based on allelic configurations discordant with the inferred population tree (ABBA-BABA test with D-statistic). Comparing the detected signals of gene flow with the contemporary geographic relationship among interspecific pairs of populations (sympatric vs. allopatric), we made two contrasting observations. At one site in the French Cevennes, we detected an excess of past interspecific gene flow, while at two sites in Switzerland we observed lower signals of past microsatellite genotypes gene flow among populations in sympatry compared to allopatric populations. These results suggest that the species boundaries between these two species depend on the past and/or present eco-geographic context in Europe, which indicates that there is no uniform link between contemporary geographic proximity and past interspecific gene flow in natural populations. Supplementary Information The online version contains supplementary material available at 10.1007/s11692-023-09612-5.
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Affiliation(s)
- Athene Giesen
- Department of Evolutionary Biology and Environmental Studies, University of Zürich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Wolf U. Blanckenhorn
- Department of Evolutionary Biology and Environmental Studies, University of Zürich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Martin A. Schäfer
- Department of Evolutionary Biology and Environmental Studies, University of Zürich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Kentaro K. Shimizu
- Department of Evolutionary Biology and Environmental Studies, University of Zürich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Rie Shimizu-Inatsugi
- Department of Evolutionary Biology and Environmental Studies, University of Zürich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Bernhard Misof
- Zoological Research Museum Alexander Koenig, Bonn, Germany
| | | | - Oliver Niehuis
- Department of Evolutionary Biology and Ecology, Institute of Biology I (Zoology), Albert Ludwig University, Freiburg, Germany
| | - Heidi E. L. Lischer
- Department of Evolutionary Biology and Environmental Studies, University of Zürich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
- Interfaculty Bioinformatics Unit, University of Bern, Bern, Switzerland
| | - Simon Aeschbacher
- Department of Evolutionary Biology and Environmental Studies, University of Zürich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Martin Kapun
- Department of Evolutionary Biology and Environmental Studies, University of Zürich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
- Division of Cell & Developmental Biology, Medical University of Vienna, Vienna, Austria
- Natural History Museum Vienna, Burgring 7, 1010 Vienna, Austria
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Kyrkjeeide MO, Meleshko O, Flatberg KI, Hassel K. Short stories from Sphagnum of rare species, taxonomy, and speciation. Ecol Evol 2023; 13:e10356. [PMID: 37484930 PMCID: PMC10361360 DOI: 10.1002/ece3.10356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 06/30/2023] [Accepted: 07/12/2023] [Indexed: 07/25/2023] Open
Abstract
Conserving species and their genetic variation are a global priority to safeguard evolutionary potential in a rapidly changing world. Species are fundamental units in research and nature management, but taxonomic work is increasingly undermined. Increasing knowledge on the species genetic diversity would aid in prioritizing conservation efforts. Sphagnum is a diverse, well-known bryophyte genus, which makes the genus suited to study speciation and cryptic variation. The species share specific characteristics and can be difficult to separate in the field. By combining molecular data with thorough morphological examination, new species have recently been discovered. Still, there are taxonomic uncertainties, even for species assessed on the IUCN Red List of threatened species. Here, we use molecular data to examine three rare species within the subgenus Acutifolia described based on morphological characters. All species have narrow distributions and limited dispersability. First, we confirm the genetic origin of S. skyense. Second, we show that S. venustum is a haploid species genetically distinct from morphologically similar species. Lastly, S. nitidulum was found to have a distinct haplotype, but cannot be genetically separated from other red Acutifolia species. We also found high genetic variation within red Acutifolia specimens, indicating the need of further morphological examination and possibly taxonomic revision. Until then, our results have shown that genetic data can aid in prioritizing targets of conservation efforts when taxonomy is unresolved. All three taxa should be further searched for by field biologists to increase knowledge about their distribution ranges.
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Affiliation(s)
| | - Olena Meleshko
- Department of Natural HistoryNorwegian University of Science and TechnologyTrondheimNorway
| | - Kjell Ivar Flatberg
- Department of Natural HistoryNorwegian University of Science and TechnologyTrondheimNorway
| | - Kristian Hassel
- Department of Natural HistoryNorwegian University of Science and TechnologyTrondheimNorway
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Hassel K, Falahati-Anbaran M, Høitomt T. Encalypta driva (sp. nov.) and its relationship to E. vulgaris in Scandinavia. LINDBERGIA 2022. [DOI: 10.25227/linbg.01115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Affiliation(s)
- Kristian Hassel
- K. Hassel (https://orcid.org/0000-0002-1906-8166) ✉ and M. Falahati-Anbaran, NTNU Univ. Museum, Norwegian Univ. of Science and Technology, Trondheim, Norway
| | - Mohsen Falahati-Anbaran
- K. Hassel (https://orcid.org/0000-0002-1906-8166) ✉ and M. Falahati-Anbaran, NTNU Univ. Museum, Norwegian Univ. of Science and Technology, Trondheim, Norway
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Flatberg KI, Hassel K, Prestø T, Kyrkjeeide MO, Shaw AJ, Ahti T. Sphagnum magniporosum (Sphagnaceae, subgenus Subsecunda) a new peatmoss species from Venezuela. LINDBERGIA 2022. [DOI: 10.25227/linbg.01161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Affiliation(s)
- Kjell Ivar Flatberg
- K. I. Flatberg, K. Hassel (https://orcid.org/0000-0002-1906-8166) ✉ and T. Prestø, Dept of Natural History, NTNU Univ. Museum, Norwegian Univ. of Science and Technology, Trondheim, Norway
| | - Kristian Hassel
- K. I. Flatberg, K. Hassel (https://orcid.org/0000-0002-1906-8166) ✉ and T. Prestø, Dept of Natural History, NTNU Univ. Museum, Norwegian Univ. of Science and Technology, Trondheim, Norway
| | - Tommy Prestø
- K. I. Flatberg, K. Hassel (https://orcid.org/0000-0002-1906-8166) ✉ and T. Prestø, Dept of Natural History, NTNU Univ. Museum, Norwegian Univ. of Science and Technology, Trondheim, Norway
| | | | - A. Jonathan Shaw
- A. J. Shaw, Dept of Biology, L.E. Anderson Bryophyte Herbarium, Duke Univ., Durham, NC, USA
| | - Teuvo Ahti
- T. Ahti, Botany Dept, Finnish Museum of Natural History, Univ. of Helsinki, Helsinki, Finland
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Meleshko O, Martin MD, Korneliussen TS, Schröck C, Lamkowski P, Schmutz J, Healey A, Piatkowski BT, Shaw AJ, Weston DJ, Flatberg KI, Szövényi P, Hassel K, Stenøien HK. Extensive Genome-Wide Phylogenetic Discordance Is Due to Incomplete Lineage Sorting and Not Ongoing Introgression in a Rapidly Radiated Bryophyte Genus. Mol Biol Evol 2021; 38:2750-2766. [PMID: 33681996 PMCID: PMC8233498 DOI: 10.1093/molbev/msab063] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The relative importance of introgression for diversification has long been a highly disputed topic in speciation research and remains an open question despite the great attention it has received over the past decade. Gene flow leaves traces in the genome similar to those created by incomplete lineage sorting (ILS), and identification and quantification of gene flow in the presence of ILS is challenging and requires knowledge about the true phylogenetic relationship among the species. We use whole nuclear, plastid, and organellar genomes from 12 species in the rapidly radiated, ecologically diverse, actively hybridizing genus of peatmoss (Sphagnum) to reconstruct the species phylogeny and quantify introgression using a suite of phylogenomic methods. We found extensive phylogenetic discordance among nuclear and organellar phylogenies, as well as across the nuclear genome and the nodes in the species tree, best explained by extensive ILS following the rapid radiation of the genus rather than by postspeciation introgression. Our analyses support the idea of ancient introgression among the ancestral lineages followed by ILS, whereas recent gene flow among the species is highly restricted despite widespread interspecific hybridization known in the group. Our results contribute to phylogenomic understanding of how speciation proceeds in rapidly radiated, actively hybridizing species groups, and demonstrate that employing a combination of diverse phylogenomic methods can facilitate untangling complex phylogenetic patterns created by ILS and introgression.
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Affiliation(s)
- Olena Meleshko
- Department of Natural History, NTNU University Museum, Norwegian University of Science and Technology, Trondheim, Norway
| | - Michael D Martin
- Department of Natural History, NTNU University Museum, Norwegian University of Science and Technology, Trondheim, Norway
| | | | | | - Paul Lamkowski
- Institute of Botany and Landscape Ecology, University of Greifswald, Greifswald, Germany
| | - Jeremy Schmutz
- United States Department of Energy, Joint Genome Institute, Berkeley, CA, USA.,HudsonAlpha Institute for Biotechnology, Huntsville, AL, USA
| | - Adam Healey
- HudsonAlpha Institute for Biotechnology, Huntsville, AL, USA
| | | | | | - David J Weston
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA.,Climate Change Science Institute, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Kjell Ivar Flatberg
- Department of Natural History, NTNU University Museum, Norwegian University of Science and Technology, Trondheim, Norway
| | - Péter Szövényi
- Department of Systematic and Evolutionary Botany & Zurich-Basel Plant Science Center, University of Zurich, Zurich, Switzerland
| | - Kristian Hassel
- Department of Natural History, NTNU University Museum, Norwegian University of Science and Technology, Trondheim, Norway
| | - Hans K Stenøien
- Department of Natural History, NTNU University Museum, Norwegian University of Science and Technology, Trondheim, Norway
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Behling AH, Shepherd LD, Cox MP. The importance and prevalence of allopolyploidy in Aotearoa New Zealand. J R Soc N Z 2019. [DOI: 10.1080/03036758.2019.1676797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Anna H. Behling
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - Lara D. Shepherd
- Museum of New Zealand Te Papa Tongarewa, Wellington, New Zealand
| | - Murray P. Cox
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand
- Bio-Protection Research Centre, Massey University, Palmerston North, New Zealand
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