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Träfflista för sökning "WFRF:(Alström Per) ;pers:(Olsson Urban)"

Sökning: WFRF:(Alström Per) > Olsson Urban

  • Resultat 1-10 av 82
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1.
  • Johansson, Ulf S, et al. (författare)
  • Build-up of the Himalayan avifauna through immigration : A biogeographical analysis of the Phylloscopus and Seicercus warblers
  • 2007
  • Ingår i: Evolution. - : Wiley. - 0014-3820 .- 1558-5646. ; 61:2, s. 324-333
  • Tidskriftsartikel (refereegranskat)abstract
    • The Himalayan mountain range is one of the most species-rich areas in the world, harboring about 8% of the world's bird species. In this study, we compare the relative importance of immigration versus in situ speciation to the build-up of the Himalayan avifauna, by evaluating the biogeographic history of the Phylloscopus/Seicercus warblers, a speciose clade that is well represented in Himalayan forests. We use a comprehensive, multigene phylogeny in conjunction with dispersal-vicariance analysis to discern patterns of speciation and dispersal within this clade. The results indicate that virtually no speciation has occurred within the Himalayas. Instead, several speciation events are attributed to dispersal into the Himalayas followed by vicariance between the Himalayas and China/Southeast Asia. Most, perhaps all, of these events appear to be pre-Pleistocene. The apparent lack of speciation within the Himalayas stands in contrast to the mountain-driven Pleistocene speciation suggested for the Andes and the East African mountains.
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  • Alström, Per, Professor, et al. (författare)
  • Phylogeny and classification of the avian superfamily Sylvioidea
  • 2006
  • Ingår i: Molecular Phylogenetics and Evolution. - Swedish Museum Nat Hist, Dept Vertebrate Zool, SE-10405 Stockholm, Sweden. Swedish Museum Nat Hist, Mol Systemat Lab, SE-10405 Stockholm, Sweden. Uppsala Univ, Evolutionary Biol Ctr, Dept Systemat Zool, SE-75236 Uppsala, Sweden. Univ Gothenburg, Dept Zool, SE-40530 Gothenburg, Sweden. : Elsevier BV. - 1055-7903 .- 1095-9513. ; 38:2, s. 381-397
  • Tidskriftsartikel (refereegranskat)abstract
    • Sylvioidea is one of the three superfamilies recognized within the largest avian radiation, the parvorder Passerida. In the present study, which is the first taxon-dense analysis of the Sylvioidea based on sequence data (nuclear myoglobin intron II and mitochondrial cytochrome b gene), we investigate the interrelationships among the four "sylvioid" clades found by previous workers, as well as the relationships within the largest of these clades. The nuclear and mitochondrial loci estimate basically the same phylogeny, with minor differences in resolution. The trees based on myoglobin and the combined data identify a strongly supported clade that includes the taxa previously allocated to Sylvioidea, except for Sitta (nuthatches), Certhia (treecreepers), Parus (tits), Remiz (penduline tits), Troglodytes and Campylorhynchus (wrens), Polioptila (gnatcatchers), and Regulus (crests/kinglets); this clade also comprises larks, which have previously been placed in the superfamily Passeroidea. We refer to this clade as Sylvioidea. This clade is further divided into 10 main, well-supported clades, which we suggest form the basis for a revised classification. (c) 2005 Elsevier Inc. All rights reserved.
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4.
  • Olsson, Urban, 1954, et al. (författare)
  • Non-monophyletic taxa and cryptic species - Evidence from a molecular phylogeny of leaf-warblers (Phylloscopus, Aves)
  • 2005
  • Ingår i: Molecular Phylogenetics and Evolution. - Univ Gothenburg, Dept Zool, SE-40530 Gothenburg, Sweden. Uppsala Univ, Evolutionary Biol Ctr, Dept Systemat Zool, SE-75236 Uppsala, Sweden. Swedish Museum Nat Hist, Dept Vertebrate Zool, SE-10405 Stockholm, Sweden. Swedish Museum Nat Hist, Mol Systemat Lab, SE-10405 Stockholm, Sweden. : Elsevier BV. - 1055-7903 .- 1095-9513. ; 36:2, s. 261-276
  • Tidskriftsartikel (refereegranskat)abstract
    • The avian taxa Cryptigata and Aeanthopneuste have been treated either as subgenera within Phylloscopus (leaf-warblers), or as a distinct genus and an informal group, respectively. The circumscriptions of these taxa have varied between authors. We estimated the phylogeny, based on the mitochondrial cytochrome b and 12S genes and the nuclear myoglobin intron 11, of all except two of the species placed in the Cryptigata and Acanthopneuste groups, as well as two recently described species and representatives of all subgenera and major clades in Phylloscopus and Seicercus recognized by previous studies. Neither Cryptigata nor Acanthopneuste is found to be monophyletic. The polytypic species P. reguloides and P. davisoni show deep divergences between some of their respective subspecies, and the latter species is non-monophyletic. We propose that the former be split into three species and the latter into two species. Seicercus xanthoschistos is nested in a clade that includes only Phylloscopus, and we recommend that it be placed in Phylloscopus. The rate of morphological divergence varies considerably among the taxa in this study. Our results emphasize the importance of dense taxon sampling in intrageneric phylogenetic studies. (c) 2005 Elsevier Inc. All rights reserved.
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  • Olsson, Urban, 1954, et al. (författare)
  • Phylogeography of Indonesian and Sino-Himalayan region bush warblers (Cettia, Aves)
  • 2006
  • Ingår i: Molecular Phylogenetics and Evolution. - : Elsevier BV. - 1055-7903 .- 1095-9513. ; 41:3, s. 556-565
  • Tidskriftsartikel (refereegranskat)abstract
    • We present a hypothesis for the phylogeny and phylogeography of a group of bush warblers in the genus Cettia, based on parts of the mitochondrial Cytochrome b gene and the nuclear myoglobin intron II (in all similar to 1.7 kb). Ancestral areas were reconstructed by dispersal-vicariance analysis and constrained Bayesian inference. The results suggest that the insular taxa in the Cettia vulcania group are most closely related to Cettia flavolivacea, and originated from a dispersal by an ancestral population in the Himalayas towards the south, to the Sunda region. From this population, a second dispersal along a different route colonized China and northern Vietnam. Hence, the Chinese taxon intricata and Vietnamese oblita, currently allocated to C. flavoliuacea, are more closely related to the vulcania group than to the other taxa in the flavolivacea group, and we propose that they be treated as conspecific with C vulcania, restricting C. flavolivacea to Myanmar and the Himalayas.
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  • Alström, Per, et al. (författare)
  • Multilocus analysis of a taxonomically densely sampled dataset reveal extensive non-monophyly in the avian family Locustellidae.
  • 2011
  • Ingår i: Molecular Phylogenetics and Evolution. - : Elsevier BV. - 1055-7903 .- 1095-9513. ; 58:3, s. 513-26
  • Tidskriftsartikel (refereegranskat)abstract
    • The phylogeny of most of the species in the avian passerine family Locustellidae is inferred using a Bayesian species tree approach (Bayesian Estimation of Species Trees, BEST), as well as a traditional Bayesian gene tree method (MrBayes), based on a dataset comprising one mitochondrial and four nuclear loci. The trees inferred by the different methods agree fairly well in topology, although in a few cases there are marked differences. Some of these discrepancies might be due to convergence problems for BEST (despite up to 1×10(9) iterations). The phylogeny strongly disagrees with the current taxonomy at the generic level, and we propose a revised classification that recognizes four instead of seven genera. These results emphasize the well known but still often neglected problem of basing classifications on non-cladistic evaluations of morphological characters. An analysis of an extended mitochondrial dataset with multiple individuals from most species, including many subspecies, suggest that several taxa presently treated as subspecies or as monotypic species as well as a few taxa recognized as separate species are in need of further taxonomic work.
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10.
  • Alström, Per, et al. (författare)
  • Non-monophyly and intricate morphological evolution within the avian family Cettiidae revealed by multilocus analysis of a taxonomically densely sampled dataset.
  • 2011
  • Ingår i: BMC Evolutionary Biology. - : Springer Science and Business Media LLC. - 1471-2148. ; 11, s. 352-
  • Tidskriftsartikel (refereegranskat)abstract
    • BACKGROUND: The avian family Cettiidae, including the genera Cettia, Urosphena, Tesia, Abroscopus and Tickellia and Orthotomus cucullatus, has recently been proposed based on analysis of a small number of loci and species. The close relationship of most of these taxa was unexpected, and called for a comprehensive study based on multiple loci and dense taxon sampling. In the present study, we infer the relationships of all except one of the species in this family using one mitochondrial and three nuclear loci. We use traditional gene tree methods (Bayesian inference, maximum likelihood bootstrapping, parsimony bootstrapping), as well as a recently developed Bayesian species tree approach (*BEAST) that accounts for lineage sorting processes that might produce discordance between gene trees. We also analyse mitochondrial DNA for a larger sample, comprising multiple individuals and a large number of subspecies of polytypic species.RESULTS: There are many topological incongruences among the single-locus trees, although none of these is strongly supported. The multi-locus tree inferred using concatenated sequences and the species tree agree well with each other, and are overall well resolved and well supported by the data. The main discrepancy between these trees concerns the most basal split. Both methods infer the genus Cettia to be highly non-monophyletic, as it is scattered across the entire family tree. Deep intraspecific divergences are revealed, and one or two species and one subspecies are inferred to be non-monophyletic (differences between methods).CONCLUSIONS: The molecular phylogeny presented here is strongly inconsistent with the traditional, morphology-based classification. The remarkably high degree of non-monophyly in the genus Cettia is likely to be one of the most extraordinary examples of misconceived relationships in an avian genus. The phylogeny suggests instances of parallel evolution, as well as highly unequal rates of morphological divergence in different lineages. This complex morphological evolution apparently misled earlier taxonomists. These results underscore the well-known but still often neglected problem of basing classifications on overall morphological similarity. Based on the molecular data, a revised taxonomy is proposed. Although the traditional and species tree methods inferred much the same tree in the present study, the assumption by species tree methods that all species are monophyletic is a limitation in these methods, as some currently recognized species might have more complex histories.
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  • Resultat 1-10 av 82

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