Publications by authors named "Anne Bruneau"

31 Publications

Judge it by its shape: a pollinator-blind approach reveals convergence in petal shape and infers pollination modes in the genus Erythrina.

Am J Bot 2021 09 29;108(9):1716-1730. Epub 2021 Sep 29.

Institut de recherche en biologie végétale and Département de Sciences biologiques, Université de Montréal, 4101 Sherbrooke East, Montréal (QC), H1X 2B2, Canada.

Premise: Pollinators are thought to exert selective pressures on plants, mediating the evolution of convergent floral shape often recognized as pollination syndromes. However, little is known about the accuracy of using petal shape for inferring convergence in pollination mode without a priori pollination information. Here we studied the genus Erythrina L. as a test case to assess whether ornithophyllous pollination modes (hummingbirds, passerines, sunbirds, or mixed pollination) can be inferred based on the evolutionary analysis of petal shape.

Methods: We characterized the two-dimensional dissected shape of standard, keel, and wing petals from 106 Erythrina species using geometric morphometrics and reconstructed a phylogenetic tree of 83 Erythrina species based on plastid trnL-F and nuclear ribosomal ITS sequences. We then used two phylogenetic comparative methods based on Ornstein-Uhlenbeck models, SURFACE and l1OU, to infer distinct morphological groups using petal shape and identify instances of convergent evolution. The effectiveness of these methods was evaluated by comparing the groups inferred to known pollinators.

Results: We found significant petal shape differences between hummingbird- and passerine-pollinated Erythrina species. Our analyses also revealed that petal combinations generally provided better inferences of pollinator types than individual petals and that the method and optimization criterion can affect the results.

Conclusions: We show that model-based approaches using petal shape can detect convergent evolution of floral shape and relatively accurately infer pollination modes in Erythrina. The inference power of the keel petals argues for a deeper investigation of their role in the pollination biology of Erythrina and other bird-pollinated legumes.
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http://dx.doi.org/10.1002/ajb2.1735DOI Listing
September 2021

Unveiling the Patterns of Reticulated Evolutionary Processes with Phylogenomics: Hybridization and Polyploidy in the genus Rosa.

Syst Biol 2021 Jul 30. Epub 2021 Jul 30.

Institut Agro, Univ Angers, INRAE, IRHS, SFR QUASAV, F-49000 Angers, France.

Reticulation, caused by hybridization and allopolyploidization, is considered an important and frequent phenomenon in the evolution of numerous plant lineages. Although both processes represent important driving forces of evolution, they are mostly ignored in phylogenetic studies involving a large number of species. Indeed only a scattering of methods exists to recover a comprehensive reticulated evolutionary history for a broad taxon sampling. Among these methods, comparisons of topologies obtained from plastid markers with those from a few nuclear sequences are favored, even though they restrict in-depth studies of hybridization and polyploidization. The genus Rosa encompasses c. 150 species widely distributed throughout the northern hemisphere and represents a challenging taxonomic group in which hybridization and polyploidization are prominent. Our main objective was to develop a general framework that would take patterns of reticulation into account in the study of the phylogenetic relationships among Rosa species. Using amplicon sequencing we targeted allele variation in the nuclear genome as well as haploid sequences in the chloroplast genome. We successfully recovered robust plastid and nuclear phylogenies and performed in-depth tests for several scenarios of hybridization using a maximum pseudo-likelihood approach on taxon subsets. Our diploid-first approach followed by hybrid and polyploid grafting resolved most of the evolutionary relationships among Rosa subgenera, sections, and selected species. Based on these results, we provide new directions for a future revision of the infrageneric classification in Rosa. The stepwise strategy proposed here can be used to reconstruct the phylogenetic relationships of other challenging taxonomic groups with large numbers of hybrid and polyploid taxa.
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http://dx.doi.org/10.1093/sysbio/syab064DOI Listing
July 2021

Reversing extinction trends: new uses of (old) herbarium specimens to accelerate conservation action on threatened species.

New Phytol 2021 04 13;230(2):433-450. Epub 2021 Jan 13.

Department of Biological Sciences, University of Calgary, Calgary, AB, T2N 1N4, Canada.

Although often not collected specifically for the purposes of conservation, herbarium specimens offer sufficient information to reconstruct parameters that are needed to designate a species as 'at-risk' of extinction. While such designations should prompt quick and efficient legal action towards species recovery, such action often lags far behind and is mired in bureaucratic procedure. The increase in online digitization of natural history collections has now led to a surge in the number new studies on the uses of machine learning. These repositories of species occurrences are now equipped with advances that allow for the identification of rare species. The increase in attention devoted to estimating the scope and severity of the threats that lead to the decline of such species will increase our ability to mitigate these threats and reverse the declines, overcoming a current barrier to the recovery of many threatened plant species. Thus far, collected specimens have been used to fill gaps in systematics, range extent, and past genetic diversity. We find that they also offer material with which it is possible to foster species recovery, ecosystem restoration, and de-extinction, and these elements should be used in conjunction with machine learning and citizen science initiatives to mobilize as large a force as possible to counter current extinction trends.
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http://dx.doi.org/10.1111/nph.17133DOI Listing
April 2021

Laser Driven Miniature Diamond Implant for Wireless Retinal Prostheses.

Adv Biosyst 2020 11 20;4(11):e2000055. Epub 2020 Oct 20.

School of Physics, University of Melbourne, Parkville, VIC, 3010, Australia.

The design and benchtop operation of a wireless miniature epiretinal stimulator implant is reported. The implant is optically powered and controlled using safe illumination at near-infrared wavelengths. An application-specific integrated circuit (ASIC) hosting a digital control unit is used to control the implant's electrodes. The ASIC is powered using an advanced photovoltaic (PV) cell and programmed using a single photodiode. Diamond packaging technology is utilized to achieve high-density integration of the implant optoelectronic circuitry, as well as individual connections between a stimulator chip and 256 electrodes, within a 4.6 mm × 3.7 mm × 0.9 mm implant package. An ultrahigh efficiency PV cell with a monochromatic power conversion efficiency of 55% is used to power the implant. On-board photodetection circuity with a bandwidth of 3.7 MHz is used for forward data telemetry of stimulation parameters. In comparison to implants which utilize inductively coupled coils, laser power delivery enables a high degree of miniaturization and lower surgical complexity. The device presented combines the benefits of implant miniaturization and a flexible stimulation strategy provided by a dedicated stimulator chip. This development provides a route to fully wireless miniaturized minimally invasive implants with sophisticated functionalities.
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http://dx.doi.org/10.1002/adbi.202000055DOI Listing
November 2020

The Origin of the Legumes is a Complex Paleopolyploid Phylogenomic Tangle Closely Associated with the Cretaceous-Paleogene (K-Pg) Mass Extinction Event.

Syst Biol 2021 Apr;70(3):508-526

Department of Systematic and Evolutionary Botany, University of Zurich, Zollikerstrasse 107, CH-8008, Zurich, Switzerland.

The consequences of the Cretaceous-Paleogene (K-Pg) boundary (KPB) mass extinction for the evolution of plant diversity remain poorly understood, even though evolutionary turnover of plant lineages at the KPB is central to understanding assembly of the Cenozoic biota. The apparent concentration of whole genome duplication (WGD) events around the KPB may have played a role in survival and subsequent diversification of plant lineages. To gain new insights into the origins of Cenozoic biodiversity, we examine the origin and early evolution of the globally diverse legume family (Leguminosae or Fabaceae). Legumes are ecologically (co-)dominant across many vegetation types, and the fossil record suggests that they rose to such prominence after the KPB in parallel with several well-studied animal clades including Placentalia and Neoaves. Furthermore, multiple WGD events are hypothesized to have occurred early in legume evolution. Using a recently inferred phylogenomic framework, we investigate the placement of WGDs during early legume evolution using gene tree reconciliation methods, gene count data and phylogenetic supernetwork reconstruction. Using 20 fossil calibrations we estimate a revised timeline of legume evolution based on 36 nuclear genes selected as informative and evolving in an approximately clock-like fashion. To establish the timing of WGDs we also date duplication nodes in gene trees. Results suggest either a pan-legume WGD event on the stem lineage of the family, or an allopolyploid event involving (some of) the earliest lineages within the crown group, with additional nested WGDs subtending subfamilies Papilionoideae and Detarioideae. Gene tree reconciliation methods that do not account for allopolyploidy may be misleading in inferring an earlier WGD event at the time of divergence of the two parental lineages of the polyploid, suggesting that the allopolyploid scenario is more likely. We show that the crown age of the legumes dates to the Maastrichtian or early Paleocene and that, apart from the Detarioideae WGD, paleopolyploidy occurred close to the KPB. We conclude that the early evolution of the legumes followed a complex history, in which multiple auto- and/or allopolyploidy events coincided with rapid diversification and in association with the mass extinction event at the KPB, ultimately underpinning the evolutionary success of the Leguminosae in the Cenozoic. [Allopolyploidy; Cretaceous-Paleogene (K-Pg) boundary; Fabaceae, Leguminosae; paleopolyploidy; phylogenomics; whole genome duplication events].
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http://dx.doi.org/10.1093/sysbio/syaa041DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8048389PMC
April 2021

Exploration of Plastid Phylogenomic Conflict Yields New Insights into the Deep Relationships of Leguminosae.

Syst Biol 2020 07;69(4):613-622

Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan 650201, China.

Phylogenomic analyses have helped resolve many recalcitrant relationships in the angiosperm tree of life, yet phylogenetic resolution of the backbone of the Leguminosae, one of the largest and most economically and ecologically important families, remains poor due to generally limited molecular data and incomplete taxon sampling of previous studies. Here, we resolve many of the Leguminosae's thorniest nodes through comprehensive analysis of plastome-scale data using multiple modified coding and noncoding data sets of 187 species representing almost all major clades of the family. Additionally, we thoroughly characterize conflicting phylogenomic signal across the plastome in light of the family's complex history of plastome evolution. Most analyses produced largely congruent topologies with strong statistical support and provided strong support for resolution of some long-controversial deep relationships among the early diverging lineages of the subfamilies Caesalpinioideae and Papilionoideae. The robust phylogenetic backbone reconstructed in this study establishes a framework for future studies on legume classification, evolution, and diversification. However, conflicting phylogenetic signal was detected and quantified at several key nodes that prevent the confident resolution of these nodes using plastome data alone. [Leguminosae; maximum likelihood; phylogenetic conflict; plastome; recalcitrant relationships; stochasticity; systematic error.].
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http://dx.doi.org/10.1093/sysbio/syaa013DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7302050PMC
July 2020

Phylogeny and biogeography of the Daniellia clade (Leguminosae: Detarioideae), a tropical tree lineage largely threatened in Africa and Madagascar.

Mol Phylogenet Evol 2020 05 3;146:106752. Epub 2020 Feb 3.

Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3DS, UK; Departamento de Botánica, Ecología y Fisiología Vegetal, Universidad de Córdoba, Campus de Rabanales, 14071 Córdoba, Spain.

The legume subfamily Detarioideae is exceptionally diverse in tropical Africa and Madagascar, compared to South America or Asia, a trend contrary to that shown by most other pantropical plant groups. We aim to elucidate the process of diversification giving rise to these high diversity levels by focussing our investigations on the Daniellia clade, which is present in both Africa and Madagascar. The Daniellia clade is an early-diverging lineage of subfamily Detarioideae (Leguminosae; pea family) and consists of three genera: Daniellia, Brandzeia and Neoapaloxylon. The species belonging to this group exhibit a wide range of habitat types. The Madagascar endemics Brandzeia (1 species) and Neoapaloxylon (3 species) occupy dry woodlands and arid succulent habitats respectively. Daniellia alsteeniana and D. oliveri are found in savannahs while the remaining eight species within Daniellia all occupy rainforest habitats. Phylogenetic analyses were generated from a dense, multi-individual species level sampling of the clade. Divergence time estimates were carried out using a molecular clock method to investigate biogeographical patterns and shifts in habitat types within the Daniellia clade, and conservation assessments were conducted to determine the levels of extinction risks these species are facing. We estimate that the Daniellia clade first emerged during the Early Eocene from an ancestor present in the rainforests of North Africa at that time, reflecting an ancestral habitat preference. There was a first major split over the course of the Eocene, giving rise to both African rainforest and Madagascan savannah lineages. With the emergence of a drier climate and vegetation type in Africa during the Eocene, it is likely that a dry-climate adapted lineage from the Daniellia clade ancestor could have dispersed through suitable savannah or woodland regions to reach Madagascar, subsequently giving rise to the savannah-adapted ancestor of Brandzeia and Neoapaloxylon in the Early Miocene. The African rainforest lineage gave rise to the genus Daniellia, which is postulated to have first diversified in the Middle Miocene, while savannah species of Daniellia emerged independently during the Pliocene, coinciding with the global rise of C4-dominated grasslands. More than half of the species in the Daniellia clade are near threatened or threatened, which highlights the need to understand the threats of anthropogenic pressures and climate change these species are facing to prioritise their conservation.
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http://dx.doi.org/10.1016/j.ympev.2020.106752DOI Listing
May 2020

Large-scale genomic sequence data resolve the deepest divergences in the legume phylogeny and support a near-simultaneous evolutionary origin of all six subfamilies.

New Phytol 2020 02 6;225(3):1355-1369. Epub 2019 Dec 6.

Department of Systematic and Evolutionary Botany, University of Zurich, Zollikerstrasse 107, CH-8008, Zurich, Switzerland.

Phylogenomics is increasingly used to infer deep-branching relationships while revealing the complexity of evolutionary processes such as incomplete lineage sorting, hybridization/introgression and polyploidization. We investigate the deep-branching relationships among subfamilies of the Leguminosae (or Fabaceae), the third largest angiosperm family. Despite their ecological and economic importance, a robust phylogenetic framework for legumes based on genome-scale sequence data is lacking. We generated alignments of 72 chloroplast genes and 7621 homologous nuclear-encoded proteins, for 157 and 76 taxa, respectively. We analysed these with maximum likelihood, Bayesian inference, and a multispecies coalescent summary method, and evaluated support for alternative topologies across gene trees. We resolve the deepest divergences in the legume phylogeny despite lack of phylogenetic signal across all chloroplast genes and the majority of nuclear genes. Strongly supported conflict in the remainder of nuclear genes is suggestive of incomplete lineage sorting. All six subfamilies originated nearly simultaneously, suggesting that the prevailing view of some subfamilies as 'basal' or 'early-diverging' with respect to others should be abandoned, which has important implications for understanding the evolution of legume diversity and traits. Our study highlights the limits of phylogenetic resolution in relation to rapid successive speciation.
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http://dx.doi.org/10.1111/nph.16290DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6972672PMC
February 2020

Corrigendum to "Miocene climate change as a driving force for multiple origins of annual species in Astragalus (Fabaceae, Papilionoideae)" [Mol. Phylogenet. Evol. 137 (2019) 210-221].

Mol Phylogenet Evol 2019 Oct 25;139:106566. Epub 2019 Jul 25.

Center of Excellence in Phylogeny, and Department of Plant Science, School of Biology, College of Science, University of Tehran, PO Box 14155-6455, Tehran, Iran. Electronic address:

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http://dx.doi.org/10.1016/j.ympev.2019.106566DOI Listing
October 2019

: A Non-polyploid Genomic Relic Within the Generally Polyploid Legume Family.

Front Plant Sci 2019 11;10:345. Epub 2019 Apr 11.

Corn Insects and Crop Genetics Research Unit, US Department of Agriculture-Agricultural Research Service, Ames, IA, United States.

Based on evolutionary, phylogenomic, and synteny analyses of genome sequences for more than a dozen diverse legume species as well as analysis of chromosome counts across the legume family, we conclude that the genus provides a plausible model for an early evolutionary form of the legume genome. The small genus is in the earliest-diverging clade in the earliest-diverging legume subfamily (Cercidoideae). The genome is physically small, and has accumulated mutations at an unusually slow rate compared to other legumes. Chromosome counts across 477 legume genera, combined with phylogenetic reconstructions and histories of whole-genome duplications, suggest that the legume progenitor had 7 chromosomes - as does . We propose a model in which a legume progenitor, with 7 chromosomes, diversified into species that would become the Cercidoideae and the remaining legume subfamilies; then speciation in the Cercidoideae gave rise to the progenitor of the genus. There is evidence for a genome duplication in the remaining Cercidoideae, which is likely due to allotetraploidy involving hybridization between a progenitor and a second diploid species that existed at the time of the polyploidy event. Outside the Cercidoideae, a set of probably independent whole-genome duplications gave rise to the five other legume subfamilies, at least four of which have predominant counts of 12-14 chromosomes among their early-diverging taxa. An earlier study concluded that independent duplications occurred in the Caesalpinioideae, Detarioideae, and Papilionoideae. We conclude that Cercis may be unique among legumes in lacking evidence of polyploidy, a process that has shaped the genomes of all other legumes thus far investigated.
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http://dx.doi.org/10.3389/fpls.2019.00345DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6499179PMC
April 2019

Miocene climate change as a driving force for multiple origins of annual species in Astragalus (Fabaceae, Papilionoideae).

Mol Phylogenet Evol 2019 08 15;137:210-221. Epub 2019 May 15.

Center of Excellence in Phylogeny, and Department of Plant Science, School of Biology, College of Science, University of Tehran, PO Box 14155-6455, Tehran, Iran. Electronic address:

Astragalus, a highly diverse genus of flowering plants with its highest center of diversity in West Asia, is a classic example of rapid species-level radiation and adaptation to a diversity of habitats throughout the world. We examined the historical biogeography of Astragalus using molecular dating and ancestral area reconstruction to understand how past climate changes, geographical patterns and transition in life history have provoked diversification of Astragalus. Our results suggest that Astragalus probably originated during the middle Miocene in West Asia, underwent rapid diversification, subsequently and repeatedly expanded its range in the Mediterranean region, and later to North America through West Europe. This distribution range was also extended toward central and eastern Asia from the Middle Miocene to Pleistocene. Several climatic and geological processes during the Miocene-Pliocene may be implicated in the diversification of the major Astragalus clades. In particular, the annual lineages, which are important elements in the Mediterranean flora of Africa and Europe and in the deserts of southwest to central Asia, have arisen in response to progressing aridity from the late Miocene onwards (between 8.6 Ma and 2.98 Ma). Diversification rate analyses indicate three rapid and recent diversification events, one at c. 11 Ma in the clade that groups most of the Astragalus s.s. (all except the Ophiocarpus sister lineage), one at c. 5 Ma in the crown group of the Hypoglottis clade, including herbaceous annual and perennial species, and the most recent one at c. 3 Ma in the spiny cushion forming Astracantha clade. Our study highlights the complexity of processes and factors shaping diversifications in Astragalus; a complex interaction among climatic modifications providing opportunities for diversification and likely coincident with the evolution of key morphological and physiological adaptations.
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http://dx.doi.org/10.1016/j.ympev.2019.05.008DOI Listing
August 2019

Phylogenomic analyses reveal an exceptionally high number of evolutionary shifts in a florally diverse clade of African legumes.

Mol Phylogenet Evol 2019 08 7;137:156-167. Epub 2019 May 7.

Evolutionary Biology and Ecology Unit, CP 160/12, Faculté des Sciences, Université Libre de Bruxelles, Av. F. D. Roosevelt 50, B-1050 Brussels, Belgium.

Detarioideae is well known for its high diversity of floral traits, including flower symmetry, number of organs, and petal size and morphology. This diversity has been characterized and studied at higher taxonomic levels, but limited analyses have been performed among closely related genera with contrasting floral traits due to the lack of fully resolved phylogenetic relationships. Here, we used four representative transcriptomes to develop an exome capture (target enrichment) bait for the entire subfamily and applied it to the Anthonotha clade using a complete data set (61 specimens) representing all extant floral diversity. Our phylogenetic analyses recovered congruent topologies using ML and Bayesian methods. Anthonotha was recovered as monophyletic contrary to the remaining three genera (Englerodendron, Isomacrolobium and Pseudomacrolobium), which form a monophyletic group sister to Anthonotha. We inferred a total of 35 transitions for the seven floral traits (pertaining to flower symmetry, petals, stamens and staminodes) that we analyzed, suggesting that at least 30% of the species in this group display transitions from the ancestral condition reconstructed for the Anthonotha clade. The main transitions were towards a reduction in the number of organs (petals, stamens and staminodes). Despite the high number of transitions, our analyses indicate that the seven characters are evolving independently in these lineages. Petal morphology is the most labile floral trait with a total of seven independent transitions in number and seven independent transitions to modification in petal types. The diverse petal morphology along the dorsoventral axis of symmetry within the flower is not associated with differences at the micromorphology of petal surface, suggesting that in this group all petals within the flower might possess the same petal identity at the molecular level. Our results provide a solid evolutionary framework for further detailed analyses of the molecular basis of petal identity.
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http://dx.doi.org/10.1016/j.ympev.2019.05.002DOI Listing
August 2019

Ecological Data Should Not Be So Hard to Find and Reuse.

Trends Ecol Evol 2019 06 2;34(6):494-496. Epub 2019 May 2.

Concordia University, Department of Biology, 7141 Sherbrooke Street West, Montreal, (QC), H4B 1R6, Canada.

Drawing upon the data deposited in publicly shared archives has the potential to transform the way we conduct ecological research. For this transformation to happen, we argue that data need to be more interoperable and easier to discover. One way to achieve these goals is to adopt domain-specific data representations.
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http://dx.doi.org/10.1016/j.tree.2019.04.005DOI Listing
June 2019

Global Succulent Biome phylogenetic conservatism across the pantropical Caesalpinia Group (Leguminosae).

New Phytol 2019 06 14;222(4):1994-2008. Epub 2019 Jan 14.

Department of Systematic & Evolutionary Botany, University of Zurich, Zollikerstrasse 107, 8008, Zurich, Switzerland.

The extent to which phylogenetic biome conservatism vs biome shifting determines global patterns of biodiversity remains poorly understood. To address this question, we investigated the biogeography and trajectories of biome and growth form evolution across the Caesalpinia Group (Leguminosae), a clade of 225 species of trees, shrubs and lianas distributed across the Rainforest, Succulent, Temperate and Savanna Biomes. We focused especially on the little-known Succulent Biome, an assemblage of succulent-rich, grass-poor, seasonally dry tropical vegetation distributed disjunctly across the Neotropics, Africa, Arabia and Madagascar. We reconstructed a time-calibrated phylogeny, assembled species occurrence data and assigned species to areas, biomes and growth forms. These data are used to estimate the frequency of transcontinental disjunctions, biome shifts and evolutionary transitions between growth forms and test for phylogenetic biome conservatism and correlated evolution of growth forms and biome shifts. We uncovered a pattern of strong phylogenetic Succulent Biome conservatism. We showed that transcontinental disjunctions confined within the Succulent Biome are frequent and that biome shifts to the Savanna, Rainforest and Temperate Biomes are infrequent and closely associated with shifts in plant growth forms. Our results suggest that the Succulent Biome comprises an ecologically constrained evolutionary arena spanning large geographical disjunctions across the tropics.
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http://dx.doi.org/10.1111/nph.15633DOI Listing
June 2019

A new phylogeny-based tribal classification of subfamily Detarioideae, an early branching clade of florally diverse tropical arborescent legumes.

Sci Rep 2018 05 2;8(1):6884. Epub 2018 May 2.

Institut de recherche en biologie végétale and Département de Sciences biologiques, Université de Montréal, 4101 Sherbrooke est, Montréal, H1X 2B2, Canada.

Detarioideae (81 genera, c. 760 species) is one of the six Leguminosae subfamilies recently reinstated by the Legume Phylogeny Working Group. This subfamily displays high morphological variability and is one of the early branching clades in the evolution of legumes. Using previously published and newly generated sequences from four loci (matK-trnK, rpL16, trnG-trnG2G and ITS), we develop a new densely sampled phylogeny to assess generic relationships and tribal delimitations within Detarioideae. The ITS phylogenetic trees are poorly resolved, but the plastid data recover several strongly supported clades, which also are supported in a concatenated plastid + ITS sequence analysis. We propose a new phylogeny-based tribal classification for Detarioideae that includes six tribes: re-circumscribed Detarieae and Amherstieae, and the four new tribes Afzelieae, Barnebydendreae, Saraceae and Schotieae. An identification key and descriptions for each of the tribes are also provided.
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http://dx.doi.org/10.1038/s41598-018-24687-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5932001PMC
May 2018

Is Amazonia a 'museum' for Neotropical trees? The evolution of the Brownea clade (Detarioideae, Leguminosae).

Mol Phylogenet Evol 2018 09 24;126:279-292. Epub 2018 Apr 24.

Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3AE, UK.

The flora of the Neotropics is unmatched in its diversity, however the mechanisms by which diversity has accumulated are debated and largely unclear. The Brownea clade (Leguminosae) is a characteristic component of the Neotropical flora, and the species within it are diverse in their floral morphology, attracting a wide variety of pollinators. This investigation aimed to estimate species divergence times and infer relationships within the group, in order to test whether the Brownea clade followed the 'cradle' or 'museum' model of diversification, i.e. whether species evolved rapidly over a short time period, or gradually over many millions of years. We also aimed to trace the spatio-temporal evolution of the clade by estimating ancestral biogeographical patterns in the group. We used BEAST to build a dated phylogeny of 73 Brownea clade species using three molecular markers (ITS, trnK and psbA-trnH), resulting in well-resolved phylogenetic relationships within the clade, as well as robust divergence time estimates from which we inferred diversification rates and ancestral biogeography. Our analyses revealed an Eocene origin for the group, after which the majority of diversification happened in Amazonia during the Miocene, most likely concurrent with climatic and geological changes caused by the rise of the Andes. We found no shifts in diversification rate over time, suggesting a gradual accumulation of lineages with low extinction rates. These results may help to understand why Amazonia is host to the highest diversity of tree species on Earth.
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http://dx.doi.org/10.1016/j.ympev.2018.04.029DOI Listing
September 2018

A new generic system for the pantropical Caesalpinia group (Leguminosae).

PhytoKeys 2016 12(71):1-160. Epub 2016 Oct 12.

Comparative Plant and Fungal Biology Department, Royal Botanic Gardens, Kew, Richmond, Surrey, TW9 3AB, United Kingdom.

The Caesalpinia group is a large pantropical clade of ca. 205 species in subfamily Caesalpinioideae (Leguminosae) in which generic delimitation has been in a state of considerable flux. Here we present new phylogenetic analyses based on five plastid and one nuclear ribosomal marker, with dense taxon sampling including 172 (84%) of the species and representatives of all previously described genera in the Caesalpinia group. These analyses show that the current classification of the Caesalpinia group into 21 genera needs to be revised. Several genera (, , and sensu Lewis, 2005) are non-monophyletic and several previously unclassified Asian species segregate into clades that merit recognition at generic rank. In addition, the near-completeness of our taxon sampling identifies three species that do not belong in any of the main clades and these are recognised as new monospecific genera. A new generic classification of the Caesalpinia group is presented including a key for the identification of genera, full generic descriptions, illustrations (drawings and photo plates of all genera), and (for most genera) the nomenclatural transfer of species to their correct genus. We recognise 26 genera, with reinstatement of two previously described genera ( Tod., R. Vig.), re-delimitation and expansion of several others (, , and ), contraction of s.s. and description of four new ones (, , and ), and make 75 new nomenclatural combinations in this new generic system.
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http://dx.doi.org/10.3897/phytokeys.71.9203DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5558824PMC
October 2016

Floral evolution and phylogeny of the Dialioideae, a diverse subfamily of tropical legumes.

Am J Bot 2017 Jul 14;104(7):1019-1041. Epub 2017 Jul 14.

Institut de Recherche en Biologie Végétale and Département de Sciences Biologiques, Université de Montréal, 4101 rue Sherbrooke Est, Montréal, Québec, H1X 2B2, Canada.

Premise Of The Study: The Dialioideae is an early diverging clade of caesalpinioid legumes containing approximately 85 species in 17 genera. Dialioideae floral morphology is highly variable and may provide clues to caesalpinioid evolution, but a well-resolved phylogeny is needed. Here, we have carried out a comprehensive morphological study of 78 Dialioideae and four outgroup species.

Methods: For all available Dialioideae DNA samples, the plastid and introns were sequenced. A combined phylogenetic analysis using the parsimony criterion was completed on a reduced taxon set for which both molecular and morphological data were available. Highly supported clades from the strict consensus tree of this analysis were then used to constrain the nodes of a second analysis on an expanded taxon set with missing molecular data for some taxa.

Key Results: Several new, highly supported relationships have been discovered at the species and genus levels. The loss of the antepetalous stamen whorl was found to be a synapomorphy for most of the clade.

Conclusions: A high degree of organ loss is common in the Dialioideae and often results in a bilaterally symmetrical flower. The absence of consistent morphological features in the Dialioideae, coupled with the small size of each florally diagnosed genus, suggests a lack of canalization in the floral evolution in early diverging legume lineages.
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http://dx.doi.org/10.3732/ajb.1600436DOI Listing
July 2017

Insights on the evolutionary origin of Detarioideae, a clade of ecologically dominant tropical African trees.

New Phytol 2017 Jun 21;214(4):1722-1735. Epub 2017 Mar 21.

Institut de recherche en biologie végétale and Département de Sciences biologiques, Université de Montréal, 4101 Sherbrooke est, Montréal, QC, H1X 2B2, Canada.

African tropical forests are generally considered less diverse than their Neotropical and Asian counterparts. By contrast, the Detarioideae is much more diverse in Africa than in South America and Asia. To better understand the evolution of this contrasting diversity pattern, we investigated the biogeographical and ecological origin of this subfamily, testing whether they originated in dry biomes surrounding the Tethys Seaway as currently hypothesized for many groups of Leguminosae. We constructed the largest time-calibrated phylogeny for the subfamily to date, reconstructed ancestral states for geography and biome/habitat, estimated diversification and extinction rates, and evaluated biome/habitat and geographic shifts in Detarioideae. The ancestral habitat of Detarioideae is postulated to be a primary forest (terra firme) originated in Africa-South America, in the early Palaeocene, after which several biome/habitat and geographic shifts occurred. The origin of Detarioideae is older than previous estimates, which postulated a dry (succulent) biome origin according to the Tethys Seaway hypothesis, and instead we reveal a post Gondwana and terra firme origin for this early branching clade of legumes. Detarioideae include some of the most dominant trees in evergreen forests and have likely played a pivotal role in shaping continental African forest diversity.
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http://dx.doi.org/10.1111/nph.14523DOI Listing
June 2017

Phylogeny and biogeography of wild roses with specific attention to polyploids.

Ann Bot 2015 Feb 29;115(2):275-91. Epub 2014 Dec 29.

Chengdu Institute of Biology, Chinese Academy of Sciences, PO Box 416, Chengdu, Sichuan 610041, China, Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Mengla, Yunnan 666303, China, Institut de Recherche en Biologie Végétale (Département de Sciences biologiques), Université de Montréal, 4101 Sherbrooke Est, Montréal, Québec H1X 2B2, Canada, Montreal Botanical Garden, 4101 Sherbrooke Est, Montréal, Québec H1X 2B2, Canada and Missouri Botanical Garden, PO Box 299, St. Louis, MO 63166-0299, USA Chengdu Institute of Biology, Chinese Academy of Sciences, PO Box 416, Chengdu, Sichuan 610041, China, Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Mengla, Yunnan 666303, China, Institut de Recherche en Biologie Végétale (Département de Sciences biologiques), Université de Montréal, 4101 Sherbrooke Est, Montréal, Québec H1X 2B2, Canada, Montreal Botanical Garden, 4101 Sherbrooke Est, Montréal, Québec H1X 2B2, Canada and Missouri Botanical Garden, PO Box 299, St. Louis, MO 63166-0299, USA

Background And Aims: The genus Rosa (150-200 species) is widely distributed throughout temperate and sub-tropical habitats from the northern hemisphere to tropical Asia, with only one tropical African species. In order to better understand the evolution of roses, this study examines infrageneric relationships with respect to conventional taxonomy, considers the extent of allopolyploidization and infers macroevolutionary processes that have led to the current distribution of the genus.

Methods: Phylogenetic relationships among 101 species of the genus Rosa were reconstructed using sequences from the plastid psbA-trnH spacer, trnL intron, trnL-F spacer, trnS-G spacer and trnG intron, as well as from nuclear glyceraldehyde 3-phosphate dehydrogenase (GAPDH), which was used to identify putative allopolyploids and infer their possible origins. Chloroplast phylogeny was used to estimate divergence times and reconstruct ancestral areas.

Key Results: Most subgenera and sections defined by traditional taxonomy are not monophyletic. However, several clades are partly consistent with currently recognized sections. Allopolyploidy seems to have played an important role in stabilizing intersectional hybrids. Biogeographic analyses suggest that Asia played a central role as a genetic reservoir in the evolution of the genus Rosa.

Conclusions: The ancestral area reconstruction suggests that despite an early presence on the American continent, most extant American species are the results of a later re-colonization from Asia, probably through the Bering Land Bridge. The results suggest more recent exchanges between Asia and western North America than with eastern North America. The current distribution of roses from the Synstylae lineage in Europe is probably the result of a migration from Asia approx. 30 million years ago, after the closure of the Turgai strait. Directions for a new sectional classification of the genus Rosa are proposed, and the analyses provide an evolutionary framework for future studies on this notoriously difficult genus.
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http://dx.doi.org/10.1093/aob/mcu245DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4551085PMC
February 2015

Ecology in the age of DNA barcoding: the resource, the promise and the challenges ahead.

Mol Ecol Resour 2014 Mar 21;14(2):221-32. Epub 2013 Oct 21.

Institut de recherche en biologie végétale, Département de sciences biologiques, Université de Montréal, 4101 Sherbrooke East, Montréal, Quebec,, Canada, H1X 2B2; Montreal Botanical Garden, 4101 Sherbrooke East, Montréal, Quebec,, Canada, H1X 2B2.

Ten years after DNA barcoding was initially suggested as a tool to identify species, millions of barcode sequences from more than 1100 species are available in public databases. While several studies have reviewed the methods and potential applications of DNA barcoding, most have focused on species identification and discovery, and relatively few have addressed applications of DNA barcoding data to ecology. These data, and the associated information on the evolutionary histories of taxa that they can provide, offer great opportunities for ecologists to investigate questions that were previously difficult or impossible to address. We present an overview of potential uses of DNA barcoding relevant in the age of ecoinformatics, including applications in community ecology, species invasion, macroevolution, trait evolution, food webs and trophic interactions, metacommunities, and spatial ecology. We also outline some of the challenges and potential advances in DNA barcoding that lie ahead.
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http://dx.doi.org/10.1111/1755-0998.12173DOI Listing
March 2014

Phylogeny reconstruction in the Caesalpinieae grade (Leguminosae) based on duplicated copies of the sucrose synthase gene and plastid markers.

Mol Phylogenet Evol 2012 Oct 12;65(1):149-62. Epub 2012 Jun 12.

Institut de recherche en biologie végétale, Département de Sciences biologiques, Université de Montréal, Montréal, Québec, Canada.

The Caesalpinieae grade (Leguminosae) forms a morphologically and ecologically diverse group of mostly tropical tree species with a complex evolutionary history. This grade comprises several distinct lineages, but the exact delimitation of the group relative to subfamily Mimosoideae and other members of subfamily Caesalpinioideae, as well as phylogenetic relationships among the lineages are uncertain. With the aim of better resolving phylogenetic relationships within the Caesalpinieae grade, we investigated the utility of several nuclear markers developed from genomic studies in the Papilionoideae. We cloned and sequenced the low copy nuclear gene sucrose synthase (SUSY) and combined the data with plastid trnL and matK sequences. SUSY has two paralogs in the Caesalpinieae grade and in the Mimosoideae, but occurs as a single copy in all other legumes tested. Bayesian and maximum likelihood phylogenetic analyses suggest the two nuclear markers are congruent with plastid DNA data. The Caesalpinieae grade is divided into four well-supported clades (Cassia, Caesalpinia, Tachigali and Peltophorum clades), a poorly supported clade of Dimorphandra Group genera, and two paraphyletic groups, one with other Dimorphandra Group genera and the other comprising genera previously recognized as the Umtiza clade. A selection analysis of the paralogs, using selection models from PAML, suggests that SUSY genes are subjected to a purifying selection. One of the SUSY paralogs, under slightly stronger positive selection, may be undergoing subfunctionalization. The low copy SUSY gene is useful for phylogeny reconstruction in the Caesalpinieae despite the presence of duplicate copies. This study confirms that the Caesalpinieae grade is an artificial group, and highlights the need for further analyses of lineages at the base of the Mimosoideae.
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http://dx.doi.org/10.1016/j.ympev.2012.05.035DOI Listing
October 2012

Morphological evolution in the variable resin-producing Detarieae (Fabaceae): do morphological characters retain a phylogenetic signal?

Ann Bot 2010 Feb 25;105(2):311-25. Epub 2009 Nov 25.

Institut de recherche en biologie végétale (Département de Sciences biologiques), Université de Montréal, Montréal, Québec H1X 2B2, Canada.

Background And Aims: Previous molecular phylogenetic studies disagree with the informal generic-level taxonomic groups based on morphology. In this study morphological characters in the caesalpinioid clade Detarieae are evaluated within a phylogenetic framework as a means of better understanding phylogenetic relationships and morphological evolution.

Methods: Morphological characters were observed and scored for representative species of Detarieae focusing on the resin-producing genera. Phylogenetic analyses were carried out with morphological characters alone and then combined with DNA sequences.

Key Results: Despite a high level of homoplasy, morphological data support several clades corresponding to those recovered in molecular phylogenetic analyses. The more strongly supported clades are each defined by at least one morphological synapomorphy. Several characters (e.g. apetaly) previously used to define informal generic groups evolved several times independently, leading to the differences observed with the molecular phylogenetic analyses. Although floral evolution is complex in Detarieae some patterns are recovered.

Conclusions: New informal taxonomic groupings are proposed based on the present findings. Floral evolution in the diverse Detarieae clade is characterized by a repeated tendency toward zygomorphy through the reduction of lateral petals and toward complete loss of petals.
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http://dx.doi.org/10.1093/aob/mcp280DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2814753PMC
February 2010

Measuring branch support in species trees obtained by gene tree parsimony.

Syst Biol 2009 Feb 25;58(1):100-13. Epub 2009 May 25.

Allan Wilson Centre for Molecular Ecology and Evolution, Massey University, Palmerston North, New Zealand.

Several methods have recently been developed that allow the reconstruction of species trees from gene trees, an important achievement in our ongoing quest to obtain reliable species phylogenies. However, considerably less attention has been given to evaluating the accuracy of species trees' estimates. Four methods for measuring branch support of species trees are tested in this study in a gene tree parsimony framework: 1) bootstrap lineages (BL) (sequences) within species, 2) bootstrap characters (BC) within genes (i.e., the standard nonparametric bootstrap), 3) bootstrap lineages and characters (BLC), and 4) posterior probability gene tree sampling (PPGTS) (where, for each resampled data set, gene trees are sampled according to their posterior probability). For each method, n species trees are reconstructed from n resampled data sets and the branch support consists in the percentage of the n species trees in which a branch is recovered. The 4 methods were tested for several species trees and for different sampling efforts (i.e., number of genes and individuals sampled) using coalescent simulations. PPGTS performed best overall with lowest Type I and II error rates, followed by BLC. The BL and BC methods had higher error rates. This suggests that in order to properly measure branch support in a species tree context, it is important to account for the uncertainty involved in reconstructing gene trees from DNA sequences as well as that involved in reconstructing the species tree from individual gene trees. With the parameters used in the simulations, sampling more individuals per species resulted in similar improvements in support values as when sampling more genes. Moreover, sampling more individuals per species appeared to be important for escaping the anomaly zone present when only 1 sequence was sampled. We also apply the 4 methods to obtain branch supports for the species phylogeny of diploid wild roses (Rosa) in North America.
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http://dx.doi.org/10.1093/sysbio/syp013DOI Listing
February 2009

Three-gene identity coefficients demonstrate that clonal reproduction promotes inbreeding and spatial relatedness in yellow-cedar, Callitropsis nootkatensis.

Evolution 2008 Oct 25;62(10):2570-9. Epub 2008 Aug 25.

Natural Resources Canada, Canadian Forest Service, Laurentian Forestry Centre, 1055, rue du P.E.P.S., c.p. 10380 Succursale Sainte-Foy, Québec QC G1V 4C7 Canada.

Asexual reproduction has the potential to promote population structuring through matings between clones as well as through limited dispersal of related progeny. Here we present an application of three-gene identity coefficients that tests whether clonal reproduction promotes inbreeding and spatial relatedness within populations. With this method, the first two genes are sampled to estimate pairwise relatedness or inbreeding, whereas the third gene is sampled from either a clone or a sexually derived individual. If three-gene coefficients are significantly greater for clones than nonclones, then clonality contributes excessively to genetic structure. First, we describe an estimator of three-gene identity and briefly evaluate its properties. We then use this estimator to test the effect of clonality on the genetic structure within populations of yellow-cedar (Callitropsis nootkatensis) using a molecular marker survey. Five microsatellite loci were genotyped for 485 trees sampled from nine populations. Our three-gene analyses show that clonal ramets promote inbreeding and spatial structure in most populations. Among-population correlations between clonal extent and genetic structure generally support these trends, yet with less statistical significance. Clones appear to contribute to genetic structure through the limited dispersal of offspring from replicated ramets of the same clonal genet, whereas this structure is likely maintained by mating among these relatives.
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http://dx.doi.org/10.1111/j.1558-5646.2008.00470.xDOI Listing
October 2008

Hybridization between the escaped Rosa rugosa (Rosaceae) and native R. blanda in eastern North America.

Am J Bot 2008 May;95(5):597-607

Institut de recherche en biologie végétale, Université de Montréal, 4101 Sherbrooke Est, Montreal, Quebec, Canada H1X 2B2.

Rosa rugosa, a vigorous ornamental shrub introduced from Asia in the 19th century, is now naturalized in coastal northeastern North America, where it occasionally grows in sympatry with the native R. blanda. To document hybridization between these species, evaluate its extent across the area of sympatry, and examine the use of morphology as a field monitoring tool, we sampled 179 individuals of parental species and putative hybrids in 13 pure and 11 mixed populations. We developed allele-specific primers to assay single nucleotide polymorphisms (SNPs) markers from one chloroplast region and four low-copy nuclear introns. Our results revealed frequent bidirectional hybridization and infrequent introgression in sympatric populations of these species. The recurrent presence of F(1) hybrids in mixed populations indicated the weakness of early-acting reproductive barriers. Morphological data were concordant with molecular data and provided additional evidence for the presence of a few backcrosses. Morphological analyses yielded diagnostic characters for identifying hybrids and monitoring the hybrid zone. Such hybridization could ultimately lead to the genetic assimilation of R. blanda in mixed populations and to the formation of invasive hybrid genotypes, a phenomenon that is of economic and ecological concern because of the increasing number of exotic species worldwide.
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http://dx.doi.org/10.3732/ajb.2007385DOI Listing
May 2008

Incorporating allelic variation for reconstructing the evolutionary history of organisms from multiple genes: An example from Rosa in North America.

Syst Biol 2006 Aug;55(4):623-36

Institut de recherche en biologie végétale, Université de Montréal, 4101 Sherbrooke Est, Montréal (Québec), H1X 2B2, Canada.

Allelic variation within individuals holds information regarding the relationships of organisms, which is expected to be particularly important for reconstructing the evolutionary history of closely related taxa. However, little effort has been committed to incorporate such information for reconstructing the phylogeny of organisms. Haplotype trees represent a solution when one nonrecombinant marker is considered, but there is no satisfying method when multiple genes are to be combined. In this paper, we propose an algorithm that converts a distance matrix of alleles to a distance matrix among organisms. This algorithm allows the incorporation of allelic variation for reconstructing the phylogeny of organisms from one or more genes. The method is applied to reconstruct the phylogeny of the seven native diploid species of Rosa sect. Cinnamomeae in North America. The glyceralgehyde 3-phosphate dehydrogenase (GAPDH), the triose phosphate isomerase (TPI), and the malate synthase (MS) genes were sequenced for 40 individuals from these species. The three genes had little genetic variation, and most species showed incomplete lineage sorting, suggesting these species have a recent origin. Despite these difficulties, the networks (NeighborNet) of organisms reconstructed from the matrix obtained with the algorithm recovered groups that more closely match taxonomic boundaries than did the haplotype trees. The combined network of individuals shows that species west of the Rocky Mountains, Rosa gymnocarpa and R. pisocarpa, form exclusive groups and that together they are distinct from eastern species. In the east, three groups were found to be exclusive: R. nitida-R. palustris, R. foliolosa, and R. blanda-R. woodsii. These groups are congruent with the morphology and the ecology of species. The method is also useful for representing hybrid individuals when the relationships are reconstructed using a phylogenetic network.
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http://dx.doi.org/10.1080/10635150600863109DOI Listing
August 2006

Polyploid and hybrid evolution in roses east of the Rocky Mountains.

Am J Bot 2006 Mar;93(3):412-25

Institut de Recherche en Biologie Végétale, Université de Montréal, 4101 Sherbrooke est, Montréal, Québec H1X 2B2 Canada;

This study investigates the impact of hybridization and polyploidy in the evolution of eastern North American roses. We explore these processes in the Rosa carolina complex (section Cinnamomeae), which consists of five diploid and three tetraploid species. To clarify the status and origins of polyploids, a haplotype network (statistical parsimony) of the glyceraldehyde 3-phosphate dehydrogenase (GAPDH) nuclear gene was estimated for polyploids of the complex and for diploids of section Cinnamomeae in North America. A genealogical approach helped to decipher the evolutionary history of polyploids from noise created by hybridization, incomplete lineage sorting, and allelic segregation. At the diploid level, species west of the Rocky Mountains are distinct from eastern species. In the east, two groups of diploids were found: one consists of R. blanda and R. woodsii and the other of R. foliolosa, R. nitida, and R. palustris. Only eastern diploids are involved in the origins of the polyploids. Rosa arkansana is derived from the blanda-woodsii group, R. virginiana originated from the foliolosa-nitida-palustris group, and R. carolina is derived from a hybrid between the two diploid groups. The distinct origins of these polyploid taxa support the hypothesis that the three polyploids are separate species.
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http://dx.doi.org/10.3732/ajb.93.3.412DOI Listing
March 2006

Evolution of triploidy in Apios americana (Leguminosae) revealed by genealogical analysis of the histone H3-D gene.

Evolution 2004 Feb;58(2):284-95

Institut de recherche en biologie végétale, Université de Montréal, 4101 rue Sherbrooke est, Montréal, Québec, Canada H1X 2B2.

Autotriploidy is normally considered to be maladaptive in plants because of its association with high levels of sterility. Nonetheless, triploid individuals are found in many plant species and play important roles in plant evolution, in particular as a first step toward tetraploid formation. However, few studies have addressed the evolutionary potential of triploid lineages, which may principally suffer from the impossibility of combining useful mutations in a single genome due to their low fertility. Therefore, triploids acquire genetic diversity only via recurrent evolution and somaclonal mutation. This study evaluates the potential of multiple origins of polyploidy as a source of genetic diversity in Apios americana, a North American legume that possesses both diploid and triploid populations. Ploidy level determination via flow cytometry shows that triploids are mainly restricted to the portion of eastern North America that was covered by ice during the Wisconsinan glaciation 18,000 years ago. This distribution implies that either selection or postglaciation colonization played a role in shaping this cytogeographic pattern. A haplotype network of the single copy nuclear histone H3-D gene reconstructed using statistical parsimony, together with single-strand conformational polymorphism analysis, shows that autotriploidy evolved at least three times in this species and that heterozygosity is high in triploids. The genetic diversity found in A. americana resulting from recurrent evolution and fixed heterozygosity increases the likelihood of producing successful genotypes and may give the opportunity for triploids to be better fit than diploids in new habitats. This suggests that triploid lineages can exhibit evolutionary potential of their own, and do not serve solely as a first step toward tetraploid formation.
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February 2004

Intergeneric and infrafamilial phylogeny of subfamily Monsteroideae (Araceae) revealed by chloroplast trnL-F sequences.

Am J Bot 2004 Mar;91(3):490-8

Department of Plant Sciences, University of Cambridge, CB2 3EA, UK;

The chloroplast trnL-F region was used as an independent data set for phylogenetic analysis of 118 aroid taxa. We investigated the intergeneric relationships of subfamily Monsteroideae (Araceae) and used this as a basis for an interspecific phylogenetic study of Rhaphidophora Hassk., the largest genus of the Monsteroideae. Results of the molecular tree were useful for inferring subfamilial and tribal circumscription and evolution in Araceae. Our results show that family Araceae consists of five clades that correspond to the subfamilies traditionally recognized. Starting from the most basal clade, these correspond to subfamilies Gymnostachydoideae and Orontioideae (proto aroids), with Lemna sp. (Lemnaceae) embedded in the Araceae and sister to the true aroids consisting of Pothoideae sister to Monsteroideae, immediately sister to Lasioideae and Aroideae. There is less agreement with existing tribal classifications. Complex relationships exist between members of the Monsteroideae. Our results show that Rhaphidophora and Epipremnum are paraphyletic with species of Rhaphidophora sampled, forming three informal groups with other genera of the Monstereae. Phylogenetic results may be used to suggest taxonomic changes to the current systematics of the monsteroids.
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http://dx.doi.org/10.3732/ajb.91.3.490DOI Listing
March 2004
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