| 1. |
- Armstrong, Kate E., et al.
(författare)
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Patterns of diversification amongst tropical regions compared: a case study in Sapotaceae.
- 2014
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Ingår i: Frontiers in Genetics. - : Frontiers Media SA. - 1664-8021. ; 5:362
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Tidskriftsartikel (refereegranskat)abstract
- Species diversity is unequally distributed across the globe,with the greatest concentration occurring in the tropics. Even within the tropics, there are significant differences in the numbers of taxa found in each continental region. Manilkara is a pantropical genus of trees in the Sapotaceae comprising c.78 species. Its distribution allows for biogeographic investigation and testing of whether rates of diversification differ amongst tropical regions. The age and geographical origin of Manilkara are inferred to determine whether Gondwanan break-up, boreotropical migration or long distance dispersal have shaped its current disjunct distribution. Diversification rates through time are also analyzed to determine whether the timing and tempo of speciation on each continent coincides with geoclimatic events. Bayesian analyses of nuclear (ITS) and plastid (rpl32-trnL,rps16-trnK,and trnS-trnFM) sequences were used to reconstruct a species level phylogeny of Manilkara and related genera in the tribe Mimusopeae. Analyses of the nuclear data using a fossil-calibrated relaxed molecular clock indicate that Manilkara evolved 32–29 million years ago (Mya) in Africa. Lineages within the genus dispersed to the Neotropics 26–18 Mya and to Asia 28–15 Mya. Higher speciation rates are found in the Neotropical Manilkara clade than in either African or Asian clades. Dating of regional diversification correlates with known palaeoclimatic events. In South America, the divergence between Atlantic coastal forest and Amazonian clades coincides with the formation of drier Cerrado and Caatinga habitats between them. In Africa diversification coincides with Tertiary cycles of aridification an duplif tof the east African plateaux. In South east Asia dispersal may have been limited by the relatively recent emergence of land in New Guinea and islands further east c.10 Mya.
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| 2. |
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| 3. |
- Gautier, Laurent, et al.
(författare)
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A new species, genus and tribe of Sapotaceae, endemic to Madagascar
- 2013
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Ingår i: Taxon. - 0040-0262 .- 1996-8175. ; 62, s. 972-983
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Tidskriftsartikel (refereegranskat)abstract
- Phylogenetic relationships of the two Malagasy Sapotaceae endemic genera Capurodendron and Tsebona have been unclear until now. Recent collections from Madagascar, as well as a better representation of the tribe Isonandreae, altogether 95 terminals, were used to estimate a phylogeny of subfamily Sapotoideae. We analysed sequences of nrDNA (ITS) and cpDNA (trnH-psbA) with Bayesian inference and parsimony jackknifing. As in previous analyses, Sapoteae and Sideroxyleae are recovered monophyletic. In addition, Isonandreae, distributed in the Indo-Pacific, is for the first time resolved as monophy- letic and sister to Sapoteae. All Malagasy accessions of Capurodendron, Tsebona, and a new species are grouped in another well-supported clade. This clade is accommodated in a new tribe Tseboneae characterized by caducous stipules, 5-merous flowers with quincuncial sepals, contorted aestivation of corolla lobes, absence of corolla appendages, one or three stamens opposite each corolla lobe, villous staminodes, seeds with an adaxial scar and plano-convex cotyledons, lacking endosperm. The new species is described in the new genus Bemangidia (B. lowryi) because it has a unique leaf venation for the tribe and combines different morphological features from Capurodendron and Tsebona. All three genera are well-supported monophy- letic groups. Bemangidia lowryi is threatened with extinction due to extensive ongoing forest destruction and is assigned a preliminary conservation status of Critically Endangered.
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| 5. |
- Potter, Daniel, et al.
(författare)
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Phylogeny and classification of Rosaceae
- 2007
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Ingår i: Plant Systematics and Evolution. - : Springer Science and Business Media LLC. - 0378-2697 .- 1615-6110. ; 266, s. 5-43
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Tidskriftsartikel (refereegranskat)
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| 6. |
- Richardson, James E., et al.
(författare)
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The influence of tectonics, sea-level changes and dispersal on migration and diversification of Isonandreae (Sapotaceae)
- 2014
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Ingår i: Botanical journal of the Linnean Society. - : Wiley-Blackwell. - 0024-4074 .- 1095-8339. ; 174:1, s. 130-140
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Tidskriftsartikel (refereegranskat)abstract
- Internal transcribed spacer (ITS) ribosomal DNA sequence data were generated for 80 of the c. 200 species of Isonandreae and were added to data from African and Neotropical representatives in subfamily Sapotoideae and outgroups in Sapotaceae. Bayesian dating and ancestral area reconstruction indicated that Isonandreae are derived from within an African grade. Multiple Australasian species or lineages are derived from Sundanian lineages in South-East Asia with stem ages originating from the late Oligocene. Sri Lankan and Indian lineages are also derived from Sundanian lineages. Our results are consistent with migration from Africa into Sundania followed by numerous over-water dispersal events across Wallace's Line into Australasia and migration from Sundania to the Indian subcontinent. Pleistocene speciation indicates that sea-level changes during that epoch could have been responsible for some species diversification in Sundania.
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| 7. |
- Rydin, Catarina, et al.
(författare)
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Deep divergences in the coffee family and the systematic position of Acranthera
- 2009
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Ingår i: Plant Systematics and Evolution. - : Springer Science and Business Media LLC. - 0378-2697 .- 1615-6110. ; 278, s. 101-123
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Tidskriftsartikel (refereegranskat)abstract
- Despite extensive efforts, there are unresolved questions on evolutionary relationships in the angiosperm family Rubiaceae. Here, information from six loci and 149 Rubiaceae taxa provide new insights. Acranthera and Coptosapelta are strongly supported as sisters. Pollen grains of Acranthera possess several features common in Rubiaceae, but amongst potential similarities with the unusual grains of Coptosapelta are the nature of the apertures andthe structure of the sexine. Luculia, Acranthera and Coptosapelta are excluded from the three subfamilies Ixoroideae, Cinchonoideae and Rubioideae. Sipaneeae and Condamineeae form a clade, sister to remaining Ixoroideae. Rondeletieae and Guettardeae are sisters to remaining Cinchonoideae. Colletoecema is sister to remaining Rubioideae, followed by the Urophylleae–Ophiorrhizeae clade. Nuclear ITS provided structured information at all phylogenetic levels, but the main gain from adding nrITS was the increased resolution. Average support values also increased but were generally high also without nrITS andthe increase was not statistically significant.
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| 8. |
- Smedmark, Jenny, et al.
(författare)
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Boreotropical migration explains hybridization between geographically distant lineages in the pantropical clade Sideroxyleae (Sapotaceae)
- 2007
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Ingår i: American Journal of Botany. - 0002-9122. ; 94:9, s. 1491-1505
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Tidskriftsartikel (refereegranskat)abstract
- To determine whether the fragmented pantropical distribution of present day Sideroxyleae primarily is the result of long-distance dispersals or represents the remnants of a once continuous distribution in the northern hemisphere, the boreotropical flora, we used phylogenetic analyses of chloroplast and nuclear ribosomal DNA data, Bayesian molecular dating, and Bayesian estimation of ancestral areas. Incongruence between the two data sets was examined with a nuclear low copy gene phylogeny to discover any occurrences of reticulate evolution. The Pacific clade Nesoluma was shown to have two distinct copies of the nuclear low copy gene AAT, one from an African and one from an American ancestral lineage, indicating that it is of allopolyploid origin. We conclude that Sideroxyleae, including the ancestral lineages of Nesoluma, were part of the boreotropical flora and entered the New World via the north Atlantic land bridge. We also suggest that the distribution of extant species resulted from the cooling climate at the end of the Eocene. Sideroxylon oxyacanthum is shown not to belong in the group, but in Chrysophylloideae. A classification reflecting phylogenetic relationships, as well as new combinations for the species in Nesoluma under Sideroxylon, is presented.
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| 9. |
- Smedmark, Jenny E. E., et al.
(författare)
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A Phylogeny of Urophylleae (Rubiaceae) based on rps16 intron data
- 2008
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Ingår i: Taxon. - 0040-0262. ; 57:1, s. 24-32
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Tidskriftsartikel (refereegranskat)abstract
- This is the first study of phylogenetic relationships within the pantropical group Urophylleae. Previous studies have included few representatives from this group and little is known about its phylogeny. Here we use sequence data from the rps16 intron to address the question of where the four genera Temnopteryx, Pentaloncha, Pleiocarpidia, and Poecilocalyx, which have sometimes been classified in this group belong. By using different outgroups we show that there is conflict regarding the resolution among lineages in Rubioideae, which partly affects the support for relationships within Urophylleae. Urophylleae is shown to consist of two sister groups, one larger consisting only of Old World taxa and one smaller including the New World genera Amphidasya and Raritebe, and as sister of these two groups the African monotypic genus Temnopteryx. Pentaloncha, Pleiocarpidia, and Poecilocalyx all belong in the large Old World clade, which only comprises taxa included in the original circumscription of Urophylleae. Relationships within this group are not completely resolved, but Poecilocalyx is found to be the sister of Stelechantha and Pleiocarpidia to be the sister of Urophyllum leucophleum. Urophyllum is paraphyletic, as it seems to include Maschalocorymbus, Pleiocarpidia, Praravinia, and Pravinaria. It is not clear from the present analysis whether Pauridiantha is monophyletic or not.
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| 10. |
- Smedmark, Jenny E. E., et al.
(författare)
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Divergence time uncertainty and historical biogeography reconstruction - an example from Urophylleae (Rubiaceae)
- 2010
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Ingår i: Journal of Biogeography. - : Wiley. - 0305-0270 .- 1365-2699. ; 37:12, s. 2260-2274
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Tidskriftsartikel (refereegranskat)abstract
- Aim When hypotheses of historical biogeography are evaluated, age estimates of individual nodes in a phylogeny often have a direct impact on what explanation is concluded to be most likely. Confidence intervals of estimated divergence times obtained in molecular dating analyses are usually very large, but the uncertainty is rarely incorporated in biogeographical analyses. The aim of this study is to use the group Urophylleae, which has a disjunct pantropical distribution, to explore how the uncertainty in estimated divergence times affects conclusions in biogeographical analysis. Two hypotheses are evaluated: (1) long-distance dispersal from Africa to Asia and the Neotropics, and (2) a continuous distribution in the boreotropics, probably involving migration across the North Atlantic Land Bridge, followed by isolation in equatorial refugia. Location Tropical and subtropical Asia, tropical Africa, and central and southern tropical America. Methods This study uses parsimony and Bayesian phylogenetic analyses of chloroplast DNA and nuclear ribosomal DNA data from 56 ingroup species, beast molecular dating and a Bayesian approach to dispersal-vicariance analysis (Bayes-DIVA) to reconstruct the ancestral area of the group, and the dispersal-extinction-cladogenesis method to test biogeographical hypotheses. Results When the two models of geographic range evolution were compared using the maximum likelihood (ML) tree with mean estimates of divergence times, boreotropical migration was indicated to be much more likely than long-distance dispersal. Analyses of a large sample of dated phylogenies did, however, show that this result was not consistent. The age estimate of one specific node had a major impact on likelihood values and on which model performed best. The results show that boreotropical migration provides a slightly better explanation of the geographical distribution patterns of extant Urophylleae than long-distance dispersal. Main conclusions This study shows that results from biogeographical analyses based on single phylogenetic trees, such as a ML or consensus tree, can be misleading, and that it may be very important to take the uncertainty in age estimates into account. Methods that account for the uncertainty in topology, branch lengths and estimated divergence times are not commonly used in biogeographical inference today but should definitely be preferred in order to avoid unwarranted conclusions.
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