| 1. |
- Barrett, C. F., et al.
(författare)
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Phylogenomics, biogeography and evolution in the American genus Brahea (Arecaceae)
- 2019
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Ingår i: Botanical Journal of the Linnean Society. - : Oxford University Press (OUP). - 0024-4074 .- 1095-8339. ; 190:3, s. 242-259
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Tidskriftsartikel (refereegranskat)abstract
- Slow rates of molecular evolution at low taxonomic levels hamper studies of relationships among species and subsequent biogeographic and evolutionary analyses. An example is the genus Brahea, which is among the most poorly understood lineages of American palms and is characterized by a wide variety of growth forms and intermediate morphological features. We generated c. 400 kb of genome-scale data from all three genomes for the 11 currently described Brahea spp. to infer phylogenetic relationships, reconstruct ancestral growth form, estimate ancestral geographical ranges and test for niche differences among closely related species with geographical overlap. Relationships receive strong support and conform to previous subgeneric assignments, except for placement of the dwarf species B. moorei in Brahea subgenus Erythea. Our robust phylogenetic hypothesis reveals trends in growth form, including an overall increase in height in the B. armata clade and independent evolution of dwarf forms from taller ancestors in the B. pimo and B. dulcis clades. Ancestral range estimation reveals roles of dispersal (e.g. B. edulis on Guadalupe Island) and putative divergence within geographical regions in some cases (e.g. in the B. armata clade) but is equivocal in others (e.g. in the B. pimo clade). We find evidence of niche non-equivalency among species in the B. armata clade in north-western Mexico and some evidence of niche non-equivalency between B. berlandieri and B. dulcis, the former of which is synonymized under B. dulcis. Our findings have implications for the complex biogeographic history in Central America and Mexico, suggesting that divergence within regions and dispersal are the predominant processes of species diversification. Future studies should include population-level sampling across the genus, along with morphological and ecological information, to assess distinctness among species and, particularly, levels of gene flow, in an integrative fashion.
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| 2. |
- Bolinder, Kristina, et al.
(författare)
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From near extinction to diversification by means of ashift in pollination mechanism in the gymnosperm relict Ephedra (Ephedraceae, Gnetales)
- 2016
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Ingår i: Botanical journal of the Linnean Society. - : Oxford University Press (OUP). - 0024-4074 .- 1095-8339. ; 180:4, s. 461-477
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Tidskriftsartikel (refereegranskat)abstract
- Pollination in gymnosperms is usually accomplished by means of wind, but some groups are insect-pollinated. We show that wind and insect pollination occur in the morphologically uniform genus Ephedra (Gnetales). Based on field experiments over several years, we demonstrate distinct differences between two Ephedra species that grow in sympatry in Greece in pollen dispersal and clump formation, insect visitations and embryo formation when insects are denied access to cones. Ephedra distachya, nested in the core clade of Ephedra, is anemophilous, which is probably the prevailing state in Ephedra. Ephedra foeminea, sister to the remaining species of the genus, is entomophilous and pollinated by a range of diurnal and nocturnal insects. The generalist entomophilous system of E.foeminea, with distinct but infrequent insect visitations, is in many respects similar to that reported for Gnetum and Welwitschia and appears ancestral in Gnetales. The Ephedra lineage is well documented already from the Early Cretaceous, but the diversity declined dramatically during the Late Cretaceous, possibly to near extinction around the Cretaceous-Palaeogene boundary. The clade imbalance between insect- and wind-pollinated lineages is larger than expected by chance and the shift in pollination mode may explain why Ephedra escaped extinction and began to diversify again.
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| 3. |
- Bouchal, Johannes M., 1979-, et al.
(författare)
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The middle Miocene palynoflora and palaeoenvironments of Eskihisar (Yatağan Basin, southwestern Anatolia): : a combined LM and SEM investigation
- 2016
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Ingår i: Botanical journal of the Linnean Society. - : John Wiley & Sons. - 0024-4074 .- 1095-8339. ; 182:1, s. 14-79
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Tidskriftsartikel (refereegranskat)abstract
- Anatolia was a crossroads for mammal migration during the Miocene due to intermittent land connections between Africa and Anatolia and persisting warm conditions. Here, we investigated a palynological section from middle Miocene sediments of Eskihisar (southwestern Anatolia) in order to establish biogeographic links of the palynoflora and to infer the palaeoenvironment. Four algal palynomorphs, nine spore taxa, eight gymnosperms, three monocots, and 67 dicot pollen types were encountered and investigated using the “single grain method” that combines light microscopy and scanning electron microscopy. Two pollen zones reflect different phases of basin development. Zonal vegetation remained fairly stable across the section and reflects heterogeneous environments including broad-leaved deciduous forest, subtropical forest, and sclerophyllous and semi-evergreen oak forest. Conifers were accessory elements in the broad-leaved deciduous forest communities and replaced these at higher elevations. Some herbaceous taxa (Plumbaginaceae) indicate scattered occurrences of sandy and/or rocky soils. Biogeographic affinities are general Northern Hemispheric, North American, and East Asian as also suggested by the macro fossil record. Only two taxa provide potential biogeographic links with the African flora. This suggests that biome shifts of plant taxa between African subtropical /tropical biomes and Anatolian (western Eurasian) temperate forests and shrublands may have been rare in the middle Miocene.
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| 4. |
- Claudel, C., et al.
(författare)
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Large-scale phylogenetic analysis of Amorphophallus (Araceae) derived from nuclear and plastid sequences reveals new subgeneric delineation
- 2017
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Ingår i: Botanical Journal of the Linnean Society. - : Oxford University Press (OUP). - 0024-4074 .- 1095-8339. ; 184:1, s. 32-45
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Tidskriftsartikel (refereegranskat)abstract
- Remarkably little is known about the evolution of the emblematic genus Amorphophallus. To shed new light on phylogenetic relationships between species of Amorphophallus and test its current classification, the first well-sampled molecular phylogenetic analysis is presented here, comprising 157 species for which we generate nuclear (ITS1) and plastid (rbcL and matK) sequences. Our combined plastid and nuclear maximum likelihood and Bayesian inferences provide a solid backbone for subgeneric delineation in supporting the existence of four major clades. These latter clades are here formally recognized as subgenera (two of which are new): Amorphophallus, Metandrium, Scutandrium and Afrophallus. Each subgenus is discussed based on selected morphological features and additional traits (e.g. distribution). Finally, our results strongly support the inclusion of the genus Pseudodracontium in Amorphophallus and the required taxonomic changes are proposed here. In addition to clarifying species relationships in Amorphophallus and proposing a new infrageneric classification, this study provides a baseline for researchers working on the evolution and biogeography of Araceae and more broadly on the tropical flora, especially in Southeast Asia.
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| 5. |
- de Faria, Aparecida Donisete, et al.
(författare)
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Towards a natural classification of Sapotaceae subfamily Chrysophylloideae in the Neotropics
- 2017
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Ingår i: Botanical journal of the Linnean Society. - : Oxford University Press (OUP). - 0024-4074 .- 1095-8339. ; 185, s. 27-55
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Tidskriftsartikel (refereegranskat)abstract
- Generic limits of Chrysophyllum and Pouteria (Chrysophylloideae, Sapotaceae) have been found to be untenable. We here search for natural lineages in Neotropical Chrysophylloideae by sampling 101 terminals for molecular sequences of nuclear ribosomal DNA (external and internal transcribed spacer), the nuclear gene RPB2 and 17 morphological characters. Data were analysed with Bayesian inference and parsimony jackknifing. Morphological traits were finally optimized onto the tree to identify the most coherent characters. The resulting phylogenetic tree suggests that the limits of the well-known genera Chrysophyllum and Pouteria must be amended. Diploon, Ecclinusa and Elaeoluma can be maintained and Chrysophyllum sections Ragala section Prieurella and the satellite gen- era Achrouteria, Cornuella, Martiusella and Nemaluma merit generic resurrection. Lucuma may be restored if the type species belongs to the clade. The accepted genera Chromolucuma, Pradosia and Sarcaulus gain strong clade support, but are embedded in a core clade of Pouteria and may be relegated to the subgeneric level if morphologi- cal studies cannot provide evidence concurring with narrow generic concepts. Circumscriptions of Micropholis and Chrysophyllum sections Chrysophyllum and Villocuspis remain unclear and must be explored by using an extended taxon sampling. We predict that yet-to-be-analysed species of Pouteria sections Franchetella, Gayella, Oxythece and Pouteria and members of the currently accepted genera Chromolucuma, Pradosia and Sarcaulus will fall inside the core clade of Pouteria when analysed.
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| 6. |
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| 7. |
- Gil-Lopez, Manuel J., et al.
(författare)
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Different historical backgrounds determine contrasting phylogeographical patterns in two co-distributed Erica species (Ericaceae) across the Strait of Gibraltar
- 2017
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Ingår i: Botanical journal of the Linnean Society. - : Oxford University Press (OUP). - 0024-4074 .- 1095-8339. ; 185:3, s. 359-375
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Tidskriftsartikel (refereegranskat)abstract
- Erica australis and Erica arborea are morphologically and ecologically similar heather species. Erica australis is restricted to the western Mediterranean Basin where it overlaps with the westernmost distribution of E. arborea. Here we investigate the role of the Strait of Gibraltar (SG) as a potential biogeographical barrier to dispersal and/or as glacial refugium in these two Erica spp. in the western Mediterranean (WMed) region with contrasting geographical origins and distributions. Samples were collected from 55 and 54 populations of E. australis and E. arborea, respectively. One individual each of 52 and 45 populations of E. australis and E. arborea, respectively, were sequenced for plastid DNA regions, and 1304 and 1214 individuals from 44 and 42 populations of E. australis and E. arborea, respectively, were genotyped using nuclear microsatellites (SSRs). Plastid DNA sequences were used to estimate divergence time of lineages and to construct haplotype networks. SSR data helped to infer population genetic diversity and fixation indices and genetic structure patterns through Bayesian analysis, analysis of molecular variance and isolation by distance. Plastid haplotype diversity of E. australis was higher in the SG than in the WMed area, whereas the opposite was found in E. arborea. SSRs revealed high genetic diversity within populations of both species and population genetic structure patterns were consistent with those retrieved from plastid DNA. The SG was identified as the likely area of origin and diversification for E. australis in the late Pliocene-Pleistocene, where it survived the Last Glacial Maximum (LGM) and expanded northwards into the western Iberian Peninsula. In contrast, two separate evolutionary lineages were found for E. arborea in the Iberian Peninsula. The SG and southern WMed areas represent the western Mediterranean expansion limit of an E. arborea lineage from East Africa/Arabia in the late Pliocene-Pleistocene, whereas the northern WMed populations were relicts from an older refugium that survived LGM in north-western Iberia. This study illustrates how geographical range and origin explain differences in the phylogeographical structure of co-distributed Mediterranean plants and highlights the role of the SG as a Pleistocene refugium and biogeographical crossroads in the Mediterranean.
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| 8. |
- Hedenäs, Lars
(författare)
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On the frequency of northern and mountain genetic variants of widespread species: essential biodiversity information in a warmer world
- 2019
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Ingår i: Botanical journal of the Linnean Society. - : Oxford University Press (OUP). - 0024-4074 .- 1095-8339. ; 191, s. 440-474
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Tidskriftsartikel (refereegranskat)abstract
- Biodiversity studies and conservation management often neglect fundamental genetic diversity, even if biodiversity loss due to reduction in genetic diversity in declining, relatively common species is probably greater than the loss resulting from disappearing rare species. Climate models suggest that global warming will especially affect high latitudes due to a higher than average temperature increase towards the poles. In widespread Northern Hemisphere species, climate warming will therefore negatively affect especially northern and mountain genetic variants (NMGVs) in the same way that it will affect species with similar distributions. To explore whether NMGVs are frequent, they were searched for in ten widespread moss species based on a wide geographical sampling in Sweden and (two-) three (-four) molecular markers per species. NeighborNet split networks and jackknife analyses showed that eight of the studied species include one or more northern or, in most cases, mountain intraspecific genetic lineages or groups of related haplotypes. Analysis of molecular variance also showed that in the two species lacking such lineages or groups the genetic composition differs between different parts of Sweden or between lowlands and mountains of the north. Haplotype or nucleotide diversity is often higher in the north or mountains than in the south or lowlands. The high incidence of NMGVs, differences in genetic composition between the study regions and the frequent high diversity in the north or mountains show that conservation of the total biodiversity must also include the genetic diversity, not just the more obvious species-level taxa with restricted northern or mountain distributions.
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| 9. |
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| 10. |
- Hedrén, Mikael, et al.
(författare)
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Seed dispersal and fine-scale genetic structuring in the asexual Nigritella miniata (Orchidaceae) in the Alps
- 2019
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Ingår i: Botanical Journal of the Linnean Society. - : Oxford University Press (OUP). - 1095-8339 .- 0024-4074. ; 190:1, s. 83-100
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Tidskriftsartikel (refereegranskat)abstract
- Orchids have minute, air-filled seeds and are considered to be efficient dispersers and colonizers. However, empirical studies show that most seeds fall within a metre of the mother plant in orchids, and that individuals standing close to each other are often closely related. A poor contribution to gene dispersal by seeds may be compensated for by more efficient dispersal by pollen, but in autogamous or agamospermous orchids this component is not available. Here, we used two highly variable simple sequence repeat loci to analyse fine-scale genetic structure in the agamospermous orchid Nigritella miniata, which is widespread in alpine grasslands in the Dolomites. We studied a densely populated area of 30 × 50 m and an enlarged area of 100 × 500 m with more scattered occurences. Sp statistics, describing the decrease in relatedness with geographical distance, were 0.1073 and 0.0609, respectively, and were among the highest values recorded for the orchid family, revealing a strong genetic structuring. However, some genotypes in the studied area were distributed at distances up to 26.5 km in the Dolomites, which suggests that long-distance seed dispersal occurs occasionally and that populations separated by long distances can still be parts of the same meta-population system.
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