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Jiang Y, Yang J, Folk RA, Zhao J, Liu J, He Z, Peng H, Yang S, Xiang C, Yu X. Species delimitation of tea plants (Camellia sect. Thea) based on super-barcodes. BMC PLANT BIOLOGY 2024; 24:181. [PMID: 38468197 PMCID: PMC10926627 DOI: 10.1186/s12870-024-04882-3] [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: 10/24/2023] [Accepted: 03/04/2024] [Indexed: 03/13/2024]
Abstract
BACKGROUND The era of high throughput sequencing offers new paths to identifying species boundaries that are complementary to traditional morphology-based delimitations. De novo species delimitation using traditional or DNA super-barcodes serve as efficient approaches to recognizing putative species (molecular operational taxonomic units, MOTUs). Tea plants (Camellia sect. Thea) form a group of morphologically similar species with significant economic value, providing the raw material for tea, which is the most popular nonalcoholic caffeine-containing beverage in the world. Taxonomic challenges have arisen from vague species boundaries in this group. RESULTS Based on the most comprehensive sampling of C. sect. Thea by far (165 individuals of 39 morphospecies), we applied three de novo species delimitation methods (ASAP, PTP, and mPTP) using plastome data to provide an independent evaluation of morphology-based species boundaries in tea plants. Comparing MOTU partitions with morphospecies, we particularly tested the congruence of MOTUs resulting from different methods. We recognized 28 consensus MOTUs within C. sect. Thea, while tentatively suggesting that 11 morphospecies be discarded. Ten of the 28 consensus MOTUs were uncovered as morphospecies complexes in need of further study integrating other evidence. Our results also showed a strong imbalance among the analyzed MOTUs in terms of the number of molecular diagnostic characters. CONCLUSION This study serves as a solid step forward for recognizing the underlying species boundaries of tea plants, providing a needed evidence-based framework for the utilization and conservation of this economically important plant group.
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Affiliation(s)
- Yinzi Jiang
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, Yunnan, China
| | - Junbo Yang
- Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, Yunnan, China
| | - Ryan A Folk
- Department of Biological Sciences, Mississippi State University, Starkville, 39762, MS, USA
| | - Jianli Zhao
- Yunnan Key Laboratory of Plant Reproductive Adaptation and Evolutionary Ecology, Laboratory of Ecology and Evolutionary Biology, School of Ecology and Environmental Sciences, Yunnan University, Kunming, 650500, Yunnan, China
| | - Jie Liu
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, Yunnan, China
| | - Zhengshan He
- Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, Yunnan, China
| | - Hua Peng
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, Yunnan, China
| | - Shixiong Yang
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, Yunnan, China.
| | - Chunlei Xiang
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, Yunnan, China.
| | - Xiangqin Yu
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, Yunnan, China.
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Calixto-Rojas M, Lira-Noriega A, Rubio-Godoy M, Pérez-Ponce de León G, Pinacho-Pinacho CD. Delimitation and species discovery in the Profundulidae fish family: Using genetic, environmental and morphologic data to address taxonomic uncertainty. Mol Phylogenet Evol 2023:107856. [PMID: 37327830 DOI: 10.1016/j.ympev.2023.107856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Revised: 06/06/2023] [Accepted: 06/07/2023] [Indexed: 06/18/2023]
Abstract
The family Profundulidae includes some one of the most enigmatic freshwater fishes of Mesoamerica: despite many attempts, a robust phylogenetic framework to delimit species is lacking, mainly due to limited morphological variation within the group. The accumulation of molecular data of profundulid fishes has led to advances in the description of new taxa, but relatively less progress has been made estimating evolutionary and phylogenetic relationships for this fish family. Here, we adopt an integrative taxonomy approach including the use of nuclear and mitochondrial DNA sequences, morphometric and ecological data, to test species boundaries in profundulid fishes in the westernmost area of their known distribution range in the states of Guerrero and Oaxaca, Mexico. Using a combination of methods for species discovery and validation based on Bayesian gene tree topologies, our analyses support the delimitation of 15 valid species of profundulid fishes - a combination of previously described species validated by this study, the synonymy of unsupported taxa, and the description of two new species. Using species delimitation methods, examination of phenotypic variation, and ecological niche characterization, we also identify five potentially new lineages which require further evidence to be erected as new species. We demonstrate that the use of an integrative taxonomy approach provides a robust methodology to delimit species in a taxonomically complex group like Profundulidae. Accurate taxonomic and ecological information is crucial for the conservation of these microendemic fishes, as several species are endangered.
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Affiliation(s)
- Miguel Calixto-Rojas
- Doctorado en Ciencias, Instituto de Ecología, A.C., Red de Estudios Moleculares Avanzados, Carretera Antigua a Coatepec 351, El Haya, Xalapa, Veracruz 91073, Mexico.
| | - Andrés Lira-Noriega
- CONACyT Research Fellow, Instituto de Ecología A.C., Red de Estudios Moleculares Avanzados, Carretera Antigua a Coatepec 351, El Haya, Xalapa, Veracruz 91073, Mexico
| | - Miguel Rubio-Godoy
- Instituto de Ecología, A.C., Red de Biología Evolutiva, Carretera Antigua a Coatepec 351, El Haya, Xalapa, Veracruz 91073, Mexico
| | - Gerardo Pérez-Ponce de León
- Escuela Nacional de Estudios Superiores unidad Mérida, Universidad Nacional Autónoma de México, Km 4.5 Carretera Mérida-Tetiz, Municipio de Ucú, Yucatán 97357, Mexico
| | - Carlos D Pinacho-Pinacho
- CONACyT Research Fellow, Instituto de Ecología A.C., Red de Estudios Moleculares Avanzados, Carretera Antigua a Coatepec 351, El Haya, Xalapa, Veracruz 91073, Mexico
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Zink RM, Klicka LB. The taxonomic basis of subspecies listed as threatened and endangered under the endangered species act. FRONTIERS IN CONSERVATION SCIENCE 2022. [DOI: 10.3389/fcosc.2022.971280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
More than 170 subspecies are listed as threatened or endangered under the US Endangered Species Act. Most of these subspecies were described decades ago on the basis of geographical variation in morphology using relatively primitive taxonomic methods. The US Fish and Wildlife Service defaults to subspecies descriptions by taxonomists working with specific groups of organisms, but there is no single definition of subspecies across plants and animals. Valid tests today usually entail molecular analyses of variation within and among populations, although there is no reason that behavioral, ecological or molecular characters could not be used, and include tests for significant differences between samples of the putative endangered subspecies and its nearest geographic relatives. We evaluated data gathered since subspecies listed under the ESA were described finding about one-third are valid (distinct evolutionary taxa), one-third are not, and one-third have not been tested. Therefore, it should not be assumed that because a subspecies occurs in a checklist, it is taxonomically valid. If the US Fish and Wildlife Service intends to continue listing subspecies, we suggest that they convene taxonomic experts representing various groups of organisms to provide a minimal set of criteria for a subspecies to be listed under the ESA.
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Chafin TK, Regmi B, Douglas MR, Edds DR, Wangchuk K, Dorji S, Norbu P, Norbu S, Changlu C, Khanal GP, Tshering S, Douglas ME. Parallel introgression, not recurrent emergence, explains apparent elevational ecotypes of polyploid Himalayan snowtrout. ROYAL SOCIETY OPEN SCIENCE 2021; 8:210727. [PMID: 34729207 PMCID: PMC8548808 DOI: 10.1098/rsos.210727] [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: 04/30/2021] [Accepted: 10/01/2021] [Indexed: 06/13/2023]
Abstract
The recurrence of similar evolutionary patterns within different habitats often reflects parallel selective pressures acting upon either standing or independently occurring genetic variation to produce a convergence of phenotypes. This interpretation (i.e. parallel divergences within adjacent streams) has been hypothesized for drainage-specific morphological 'ecotypes' observed in polyploid snowtrout (Cyprinidae: Schizothorax). However, parallel patterns of differential introgression during secondary contact are a viable alternative hypothesis. Here, we used ddRADseq (N = 35 319 de novo and N = 10 884 transcriptome-aligned SNPs), as derived from Nepali/Bhutanese samples (N = 48 each), to test these competing hypotheses. We first employed genome-wide allelic depths to derive appropriate ploidy models, then a Bayesian approach to yield genotypes statistically consistent under the inferred expectations. Elevational 'ecotypes' were consistent in geometric morphometric space, but with phylogenetic relationships at the drainage level, sustaining a hypothesis of independent emergence. However, partitioned analyses of phylogeny and admixture identified subsets of loci under selection that retained genealogical concordance with morphology, suggesting instead that apparent patterns of morphological/phylogenetic discordance are driven by widespread genomic homogenization. Here, admixture occurring in secondary contact effectively 'masks' previous isolation. Our results underscore two salient factors: (i) morphological adaptations are retained despite hybridization and (ii) the degree of admixture varies across tributaries, presumably concomitant with underlying environmental or anthropogenic factors.
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Affiliation(s)
- Tyler K. Chafin
- Department of Biological Sciences, University of Arkansas, Fayetteville, AR 72701, USA
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder 80309, USA
| | - Binod Regmi
- Department of Biological Sciences, University of Arkansas, Fayetteville, AR 72701, USA
- National Institute of Arthritis, Musculoskeletal and Skin Diseases (NIAMS), National Institutes of Health, Bethesda, MD 20892, USA
| | - Marlis R. Douglas
- Department of Biological Sciences, University of Arkansas, Fayetteville, AR 72701, USA
| | - David R. Edds
- Department of Biological Sciences, Emporia State University, Emporia, KS 66801, USA
| | - Karma Wangchuk
- Department of Biological Sciences, University of Arkansas, Fayetteville, AR 72701, USA
- National Research and Development Centre for Riverine and Lake Fisheries, Ministry of Agriculture and Forests, Royal Government of Bhutan, Haa, Bhutan
| | - Sonam Dorji
- National Research and Development Centre for Riverine and Lake Fisheries, Ministry of Agriculture and Forests, Royal Government of Bhutan, Haa, Bhutan
| | - Pema Norbu
- National Research and Development Centre for Riverine and Lake Fisheries, Ministry of Agriculture and Forests, Royal Government of Bhutan, Haa, Bhutan
| | - Sangay Norbu
- National Research and Development Centre for Riverine and Lake Fisheries, Ministry of Agriculture and Forests, Royal Government of Bhutan, Haa, Bhutan
| | - Changlu Changlu
- National Research and Development Centre for Riverine and Lake Fisheries, Ministry of Agriculture and Forests, Royal Government of Bhutan, Haa, Bhutan
| | - Gopal Prasad Khanal
- National Research and Development Centre for Riverine and Lake Fisheries, Ministry of Agriculture and Forests, Royal Government of Bhutan, Haa, Bhutan
| | - Singye Tshering
- National Research and Development Centre for Riverine and Lake Fisheries, Ministry of Agriculture and Forests, Royal Government of Bhutan, Haa, Bhutan
| | - Michael E. Douglas
- Department of Biological Sciences, University of Arkansas, Fayetteville, AR 72701, USA
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Chafin TK, Douglas MR, Bangs MR, Martin BT, Mussmann SM, Douglas ME. Taxonomic Uncertainty and the Anomaly Zone: Phylogenomics Disentangle a Rapid Radiation to Resolve Contentious Species (Gila robusta Complex) in the Colorado River. Genome Biol Evol 2021; 13:evab200. [PMID: 34432005 PMCID: PMC8449829 DOI: 10.1093/gbe/evab200] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/19/2021] [Indexed: 12/18/2022] Open
Abstract
Species are indisputable units for biodiversity conservation, yet their delimitation is fraught with both conceptual and methodological difficulties. A classic example is the taxonomic controversy surrounding the Gila robusta complex in the lower Colorado River of southwestern North America. Nominal species designations were originally defined according to weakly diagnostic morphological differences, but these conflicted with subsequent genetic analyses. Given this ambiguity, the complex was re-defined as a single polytypic unit, with the proposed "threatened" status under the U.S. Endangered Species Act of two elements being withdrawn. Here we re-evaluated the status of the complex by utilizing dense spatial and genomic sampling (n = 387 and >22 k loci), coupled with SNP-based coalescent and polymorphism-aware phylogenetic models. In doing so, we found that all three species were indeed supported as evolutionarily independent lineages, despite widespread phylogenetic discordance. To juxtapose this discrepancy with previous studies, we first categorized those evolutionary mechanisms driving discordance, then tested (and subsequently rejected) prior hypotheses which argued phylogenetic discord in the complex was driven by the hybrid origin of Gila nigra. The inconsistent patterns of diversity we found within G. robusta were instead associated with rapid Plio-Pleistocene drainage evolution, with subsequent divergence within the "anomaly zone" of tree space producing ambiguities that served to confound prior studies. Our results not only support the resurrection of the three species as distinct entities but also offer an empirical example of how phylogenetic discordance can be categorized within other recalcitrant taxa, particularly when variation is primarily partitioned at the species level.
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Affiliation(s)
- Tyler K Chafin
- Department of Biological Sciences, University of Arkansas, Fayetteville, Arkansas, USA
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, Colorado, USA
| | - Marlis R Douglas
- Department of Biological Sciences, University of Arkansas, Fayetteville, Arkansas, USA
| | - Max R Bangs
- Department of Biological Sciences, University of Arkansas, Fayetteville, Arkansas, USA
- Department of Biological Science, Florida State University, Tallahassee, Florida, USA
| | - Bradley T Martin
- Department of Biological Sciences, University of Arkansas, Fayetteville, Arkansas, USA
- Global Campus, University of Arkansas, Fayetteville, Arkansas, USA
| | - Steven M Mussmann
- Department of Biological Sciences, University of Arkansas, Fayetteville, Arkansas, USA
- Southwestern Native Aquatic Resources and Recovery Center, U.S. Fish & Wildlife Service, Dexter, New Mexico, USA
| | - Michael E Douglas
- Department of Biological Sciences, University of Arkansas, Fayetteville, Arkansas, USA
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Guinand B, Oral M, Tougard C. Brown trout phylogenetics: A persistent mirage towards (too) many species. JOURNAL OF FISH BIOLOGY 2021; 99:298-307. [PMID: 33483952 DOI: 10.1111/jfb.14686] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 12/28/2020] [Accepted: 01/19/2021] [Indexed: 06/12/2023]
Affiliation(s)
- Bruno Guinand
- ISEM, Université de Montpellier, CNRS, IRD, EPHE, Montpellier, France
| | - Münevver Oral
- Faculty of Fisheries and Aquatic Science, Recep Tayyip Erdogan University, Rize, Turkey
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Moyer GR, Shaw R, Wertz T. Mitochondrial DNA Barcoding Reveals First Documented Evidence of Golden Redhorse (Moxostoma erythrurum) in the Susquehanna River, Pennsylvania. Northeast Nat (Steuben) 2021. [DOI: 10.1656/045.028.0204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- Gregory R Moyer
- Department of Natural Resources, Mansfield University, Mansfield, PA 16933
| | - Ryan Shaw
- Department of Natural Resources, Mansfield University, Mansfield, PA 16933
| | - Timothy Wertz
- Pennsylvania Department of Environmental Protection, Harrisburg, PA 17101
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Bangs MR, Douglas MR, Brunner PC, Douglas ME. Reticulate evolution as a management challenge: Patterns of admixture with phylogenetic distance in endemic fishes of western North America. Evol Appl 2020; 13:1400-1419. [PMID: 32684966 PMCID: PMC7359839 DOI: 10.1111/eva.13042] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2019] [Revised: 05/20/2020] [Accepted: 05/26/2020] [Indexed: 12/12/2022] Open
Abstract
Admixture in natural populations is a long-standing management challenge, with population genomic approaches offering means for adjudication. We now more clearly understand the permeability of species boundaries and the potential of admixture for promoting adaptive evolution. These issues particularly resonate in western North America, where tectonism and aridity have fragmented and reshuffled rivers over millennia, in turn promoting reticulation among endemic fishes, a situation compounded by anthropogenic habitat modifications and non-native introductions. The melding of historic and contemporary admixture has both confused and stymied management. We underscore this situation with a case study that quantifies basin-wide admixture among a group of native and introduced fishes by employing double-digest restriction site-associated DNA (ddRAD) sequencing. Our approach: (a) quantifies the admixed history of 343 suckers (10 species of Catostomidae) across the Colorado River Basin; (b) gauges admixture within the context of phylogenetic distance and "ecological specialization"; and (c) extrapolates potential drivers of introgression across hybrid crosses that involve endemic as well as invasive species. Our study extends across an entire freshwater basin and expands previous studies more limited in scope both geographically and taxonomically. Our results detected admixture involving all 10 species, with habitat alterations not only accelerating the breakdown of reproductive isolation, but also promoting introgression. Hybridization occurred across the genus despite phylogenetic distance, whereas introgression was only detected within subgenera, implicating phylogenetic distance and/or ecological specialization as drivers of reproductive isolation. Understanding the extent of admixture and reproductive isolation across multiple species serves to disentangle their reticulate evolutionary histories and provides a broadscale perspective for basin-wide conservation and management.
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Affiliation(s)
- Max R. Bangs
- Department of Biological SciencesUniversity of ArkansasFayettevilleARUSA
- Department of Biological SciencesFlorida State UniversityTallahasseeFLUSA
| | - Marlis R. Douglas
- Department of Biological SciencesUniversity of ArkansasFayettevilleARUSA
| | - Patrick C. Brunner
- Integrative BiologySwiss Federal Institute of Technology (ETH)ZürichSwitzerland
| | - Michael E. Douglas
- Department of Biological SciencesUniversity of ArkansasFayettevilleARUSA
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