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Sökning: WFRF:(Ohlson Jan I.)

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1.
  • Divakar, Pradeep K., et al. (författare)
  • Evolution of complex symbiotic relationships in a morphologically derived family of lichen-forming fungi
  • 2015
  • Ingår i: New Phytologist. - : Wiley. - 0028-646X .- 1469-8137. ; 208:4, s. 1217-1226
  • Tidskriftsartikel (refereegranskat)abstract
    • We studied the evolutionary history of the Parmeliaceae (Lecanoromycetes, Ascomycota), one of the largest families of lichen-forming fungi with complex and variable morphologies, also including several lichenicolous fungi. We assembled a six-locus data set including nuclear, mitochondrial and low-copy protein-coding genes from 293 operational taxonomic units (OTUs). The lichenicolous lifestyle originated independently three times in lichenized ancestors within Parmeliaceae, and a new generic name is introduced for one of these fungi. In all cases, the independent origins occurred c. 24 million yr ago. Further, we show that the Paleocene, Eocene and Oligocene were key periods when diversification of major lineages within Parmeliaceae occurred, with subsequent radiations occurring primarily during the Oligocene and Miocene. Our phylogenetic hypothesis supports the independent origin of lichenicolous fungi associated with climatic shifts at the Oligocene-Miocene boundary. Moreover, diversification bursts at different times may be crucial factors driving the diversification of Parmeliaceae. Additionally, our study provides novel insight into evolutionary relationships in this large and diverse family of lichen-forming ascomycetes.
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2.
  • Johansson, Ulf S., 1970-, et al. (författare)
  • A complete multilocus species phylogeny of the tits and chickadees (Aves:Paridae)
  • 2013
  • Ingår i: Molecular Phylogenetics and Evolution. - : Elsevier BV. - 1055-7903 .- 1095-9513. ; 69:3, s. 852-860
  • Tidskriftsartikel (refereegranskat)abstract
    • The avian family Paridae (tits and chickadees) contains c. 55 species distributed in the Palearctic, Nearctic, Afrotropics and Indomalaya. The group includes some of the most well-known and extensively studied avian species, and the evolutionary history, in particular the post-glacial colonization of the northern latitudes, has been comparably well-studied for several species. Yet a comprehensive phylogeny of the whole clade is lacking. Here, we present the first complete species phylogeny for the group based on sequence data front two nuclear introns and one mitochondrial gene for 67 taxa of parids. Our results strongly support the inclusion of the Fire-capped Tit (Cephalopyrus flammiceps), currently placed in the Remizidae, as the most basal member of the Paridae. The Yellow-browed Tit (Sylviparus modestus) and the Sultan Tit (Melanochlora sultanea) constitute the next two sequential branches whereas the remaining tits fall into two large clades, one of which contains the seed hoarding and nest excavating species. The indicated clades within these two groups are largely congruent with recent classifications, but with several unforeseen relationships, such as non-monophyly of the Sombre Tit (Poecile lugubris) and the Marsh Tit (Poecile palustris), as well as non-monophyly of both the African gray and the African black tits. Further, our results support a close relationship between the White-fronted Tit (Parus semilarvatus) and the varied Tit (Poecile varius) as well as a close relationship between the White-naped Tit (Parus nuchalis) and the Yellow-cheeked and Black-bred tits (Parus spilonotus and P. xanthogenys). Finally, Hume's Ground-tit (Pseudopodoces humilis) is found to be closely related to the Green-backed Tit (Parus monticolus) and the Great Tit (Parus major). We propose a new classification that is in accordance with this phylogeny. 
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3.
  • Sun, Chengjun, et al. (författare)
  • CRYAB-650 C>G (rs2234702) affects susceptibility to type 1 diabetes and IAA-positivity in Swedish population
  • 2012
  • Ingår i: Human Immunology. - : Elsevier. - 0198-8859 .- 1879-1166. ; 73:7, s. 759-766
  • Tidskriftsartikel (refereegranskat)abstract
    • BACKGROUND: Single nucleotide polymorphisms (SNPs) in the promoter region of CRYAB gene have been associated with in multiple sclerosis. CRYAB gene, which encodes alpha B-crystallin (a member of small heat shock protein), was reported as a potential autoimmune target. In this study we investigated whether SNPs in the promoter region of CRYAB gene were also important in the etiology of Type 1 diabetes (T1D).METHODS: Genotyping of SNPs in the promoter region of CRYAB gene was performed in a Swedish cohort containing 444 T1D patients and 350 healthy controls. Three SNPs were included in this study: CRYAB-652 A>G (rs762550), -650 C>G (rs2234702) and -249 C > G (rs14133). Two SNPs (CRYAB-652 and -650) were not included in previous genome wide association studies.RESULTS: CRYAB-650 (rs2234702)*C allele was significantly more frequent in patients than in controls (OR = 1.48, Pc = 0.03). CRYAB-650*C allele was associated with IAA positivity (OR = 8.17, Pc < 0.0001) and IA-2A positivity (OR = 2.14, Pc = 0.005) in T1D patients. This association with IAA was amplified by high-risk HLA carrier state (OR = 10.6, P < 0.0001). No association was found between CRYAB-650 and other autoantibody positivity (GADA and ICA). CRYAB haplotypes were also associated with IAA and IA-2A positivity (highest OR = 2.07 and 2.11, respectively), these associations remain in high HLA-risk T1D patients.CONCLUSIONS: CRYAB-650 was associated with T1D in the Swedish cohort we studied. CRYAB-650*C allele might confers susceptibility to the development of T1D. CRYAB-650 was also associated with the development of IAA-positivity in T1D patients, especially in those carrying T1D high-risk HLA haplotypes.
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  • Christidis, Les, et al. (författare)
  • The suboscine passerines
  • 2020
  • Ingår i: <em>The Largest Avian Radiation</em>. - Barcelona : Lynx Edicions. - 9788416728336 ; , s. 65-65
  • Bokkapitel (övrigt vetenskapligt/konstnärligt)
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6.
  • Ericson, Per G P, 1956-, et al. (författare)
  • Diversification of Neoaves : integration of molecular sequence data and fossils.
  • 2006
  • Ingår i: Biology Letters. - : The Royal Society. - 1744-9561 .- 1744-957X. ; 2:4, s. 543-7
  • Tidskriftsartikel (refereegranskat)abstract
    • Patterns of diversification and timing of evolution within Neoaves, which includes almost 95% of all bird species, are virtually unknown. On the other hand, molecular data consistently indicate a Cretaceous origin of many neoavian lineages and the fossil record seems to support an Early Tertiary diversification. Here, we present the first well-resolved molecular phylogeny for Neoaves, together with divergence time estimates calibrated with a large number of stratigraphically and phylogenetically well-documented fossils. Our study defines several well-supported clades within Neoaves. The calibration results suggest that Neoaves, after an initial split from Galloanseres in Mid-Cretaceous, diversified around or soon after the K/T boundary. Our results thus do not contradict palaeontological data and show that there is no solid molecular evidence for an extensive pre-Tertiary radiation of Neoaves.
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7.
  • Ericson, Per G. P., et al. (författare)
  • Diversification of Neoaves through time : Integration of molecular sequence data and fossils
  • 2006
  • Ingår i: Biology Letters. - : The Royal Society. - 1744-9561 .- 1744-957X. ; 2:4, s. 543-547
  • Tidskriftsartikel (refereegranskat)abstract
    • Patterns of diversification and timing of evolution within Neoaves, which includes almost 95% of all bird species, are virtually unknown. On the other hand, molecular data consistently indicate a Cretaceous origin of many neoavian lineages and the fossil record seems to support an Early Tertiary diversification. Here, we present the first well-resolved molecular phylogeny for Neoaves, together with divergence time estimates calibrated with a large number of stratigraphically and phylogenetically well-documented fossils. Our study defines several well-supported clades within Neoaves. The calibration results suggest that Neoaves, after an initial split from Galloanseres in Mid-Cretaceous, diversified around or soon after the K/T boundary. Our results thus do not contradict palaeontological data and show that there is no solid molecular evidence for an extensive pre-Tertiary radiation of Neoaves.
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8.
  • Ericson, Per G P, 1956-, et al. (författare)
  • Higher-level phylogeny and morphological evolution of tyrant flycatchers, cotingas, manakins, and their allies (Aves : Tyrannida).
  • 2006
  • Ingår i: Molecular Phylogenetics and Evolution. - : Elsevier BV. - 1055-7903 .- 1095-9513. ; 40:2, s. 471-83
  • Tidskriftsartikel (refereegranskat)abstract
    • Despite increased understanding of higher-level relationships in passerine birds in the last 15 years, the taxonomic boundaries and phylogenetic interrelationships of the major groups of the Tyrannida (including the cotingas, manakins, tityrines, and tyrant flycatchers) remain unclear. Here, we present an analysis of DNA sequence data obtained from two nuclear exons, three introns, and one mitochondrial gene for 26 genera of Tyrannida and 6 tracheophone outgroups. The analysis resulted in well-supported hypotheses about the earliest evolution within Tyrannida. The Cotingidae, Pipridae, Tityrinae (sensu) [Prum, R.O., Rice, N.H., Mobley, J.A., Dimmick, W.W., 2000. A preliminary phylogenetic hypothesis for the cotingas (Cotingidae) based on mitochondrial DNA. Auk 117, 236-241], Tyrannidae, and the tyrannid subfamiles Tyranninae and Pipromorphinae (sensu) [Sibley, C.G., Monroe, B. L. Jr., 1990. Distribution and Taxonomy of Birds of the World. Yale University Press, New Haven, CT] were all found to be reciprocally monophyletic (given the present taxon sampling). The Cotingidae and Pipridae form a clade that is the sister group to a well-supported clade including Oxyruncus, the Tityrinae, Piprites, and the Tyrannidae. Oxyruncus is the sister group to the Tityrinae, and Piprites is placed as the sister group to the Tyrannidae. The tyrannid subfamilies Tyranninae and Pipromorphinae are monophyletic sister taxa, but the relationships of Platyrinchus mystaceus to these two clades remains ambiguous. The presence of medial (=internal) cartilages in the syrinx is a synapomorphy for the Oxyruncus-Tityrinae-Piprites-Tyrannidae clade. Although morphological synapomorphies currently support the monophyly of both the Pipridae and the Cotingidae, convergences and/or reversals in morphological character states are common in Tyrannida. The relationship between Oxyruncus and the Tityrinae is congruent with additional syringeal synapomorphies and allozyme distance data. Accordingly, we propose the recognition the family Tityridae within the Tyrannida to include the genera Schiffornis, Laniisoma, Laniocera, Iodopleura, Xenopsaris, Pachyramphus, Tityra, and Oxyruncus.
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10.
  • Fjeldså, Jon, et al. (författare)
  • An updated classification of passerine birds
  • 2020
  • Ingår i: <em>The Largest Avian Radiation</em>. - Barcelona : Lynx Edicions. - 9788416728336 ; , s. 45-63
  • Bokkapitel (övrigt vetenskapligt/konstnärligt)
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  • Ohlson, Jan I, et al. (författare)
  • A molecular phylogeny of the cotingas (Aves : Cotingidae).
  • 2007
  • Ingår i: Molecular Phylogenetics and Evolution. - : Elsevier BV. - 1055-7903 .- 1095-9513. ; 42:1, s. 25-37
  • Tidskriftsartikel (refereegranskat)abstract
    • The phylogenetic relationships of members of Cotingidae were investigated using >2100 bp of sequence data from two nuclear introns (myoglobin intron 2 and G3PDH intron 11) and one protein-coding mitochondrial gene (cytochrome b). Strong support was found for a monophyletic clade including 23 traditional cotingid genera, corresponding to the Cotingidae sensu [Remsen, J.V. Jr., Jaramillo, A., Nores, M., Pacheco, J.F., Robbins, M.B., Schulenberg, T.S., Stiles, F.G., da Silva, J.M.C., Stotz, D.F., Zimmer, K.J., 2005. Version 2005-11-15. A classification of the bird species of South America. American Ornithologists' Union. ]. Neither Oxyruncus nor any of the genera in Tityrinae sensu [Prum, R.O, Lanyon, W.E., 1989. Monophyly and phylogeny of the Schiffornis group (Tyrannoidea). Condor 91, 444-461.] are members of Cotingidae. Within Cotingidae a polytomy of four well-supported clades was recovered: (1) the fruiteaters Pipreola and Ampelioides; (2) the Ampelion group, including Phytotoma; (3) Rupicola and Phoenicircus; and (4) the 'core cotingas' consisting of the remainder of the Cotingas (e.g. fruitcrows, Cotinga, Procnias, Lipaugus, and Carpodectes), with Snowornis in a basal position. The separation of Snowornis from Lipaugus [Prum, R.O, Lanyon, W.E., 1989. Monophyly and phylogeny of the Schiffornis group (Tyrannoidea). Condor 91, 444-461.] was strongly supported, as were the close relationships between Gymnoderus and Conioptilon, and between Tijuca and Lipaugus. However, basal relationships among 'core cotinga' clades were not resolved.
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19.
  • Ohlson, Jan I, et al. (författare)
  • A revised classification of the fluvicoline tyrant flycatchers (Passeriformes, Tyrannidae, Fluvicolinae)
  • 2020
  • Ingår i: Zootaxa. - 1175-5326 .- 1175-5334. ; 4747:1, s. 167-176
  • Tidskriftsartikel (refereegranskat)abstract
    • A new classification is proposed for the subfamily Fluvicolinae in the New World Flycatchers (Tyrannidae), basedon the results of a previously published phylogeny including more than 90% of the species. In this classification wepropose one new family level name (Ochthoecini) and one new generic name (Scotomyias). We also resurrect threegenera (Heteroxolmis, Pyrope and Nengetus) and subsume five (Tumbezia, Lathrotriccus, Polioxolmis, Neoxolmis and Myiotheretes) into other genera to align the classification with the current understanding of phylogenetic relationships inFluvicolinae.
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20.
  • Ohlson, Jan I, et al. (författare)
  • Molecular phylogeny of the manakins (Aves : Passeriformes
  • 2013
  • Ingår i: Molecular Phylogenetics and Evolution. - : Elsevier BV. - 1055-7903 .- 1095-9513. ; 69:3, s. 796-804
  • Tidskriftsartikel (refereegranskat)abstract
    • The phylogenetic relationships within the manakin family (Pipridae) were investigated with sequence data from three nuclear introns and one mitochondrial protein-coding gene. This study confirms a sister group relationship between Neopelminae and Piprinae. We also find support for dividing the Piprinae into two principal clades: Ilicurini and Piprini. The genera Pipra and Chloropipo are found to be polyphyletic. Chloropipo species are placed in three different clades, including two species in an unresolved position alongside Ilicurini and Piprini. We propose a new classification of the family, where the most important modifications include recognizing the genus Ceratopipra for five species formerly placed in Pipra and the erection of a new genus for Chloropipo holochlora.
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21.
  • Ohlson, Jan I., 1966- (författare)
  • Molecular phylogeny of tyrant flycatchers, cotingas, manakins and their allies (Aves: Tyrannida)
  • 2008
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Tyrannida is a monophyletic clade that together with Furnariida constitutes the New World suboscines. The ca 560 species in Tyrannida are traditionally divided between three families: Tyrannidae (tyrant flycatchers), Cotingidae (cotingas) and Pipridae (manakins). They are most diverse in South America, where they make up roughly one third of the passerine diversity in most habitats. Constituting such a substantial part of South America’s avian diversity, they are of great importance for the understanding of South American biogeography, but also for studies of more general issues in evolutionary biology, e.g. patterns of adaptive radiation. However, their usefulness in such studies has been limited by the lack of a robust and well-resolved phylogeny for the group. Although three or four main lineages are universally recognized, phylogenetic relationships in the group are generally poorly understood and the affinities of a large number of genera are uncertain.The principal aim of this thesis is to reconstruct a well-resolved phylogenetic hypothesis for Tyrannida, which can serve as a platform for further studies of suboscine systematics and of broader issues in evolutionary biology. This has been achieved by employing comprehensive taxon sampling, DNA sequence data from multiple genes and model-based phylogenetic methods. The resulting phylogenies are generally well resolved and lend support to several earlier hypotheses of relationships in Tyrannida, but further clarify the basal divergences and show that all insectivorous groups form a monophyletic clade. Several novel relationships are revealed, most importantly that nearly all of the genera of debated affinities represent deep lineages in the insectivorous clade. Early evolution of Tyrannida took place in humid forest, and nearly all species tied to open habitats belong in a monophyletic clade that radiated in response to the cooling and drying climatic trend from the Mid Miocene and onwards.
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23.
  • Ohlson, Jan I, et al. (författare)
  • Phylogeny and classification of the New World suboscines (Aves, Passeriformes).
  • 2013
  • Ingår i: Zootaxa. - 1175-5326 .- 1175-5334. ; 3613, s. 1-35
  • Tidskriftsartikel (refereegranskat)abstract
    • Here we present a phylogenetic hypothesis for the New World suboscine radiation, based on a dataset comprising of 219 terminal taxa and five nuclear molecular markers (ca. 6300 bp). We also estimate ages of the main clades in this radiation. This study corroborates many of the recent insights into the phylogenetic relationships of New World suboscines. It further clarifies a number of cases for which previous studies have been inconclusive, such as the relationships of Conopophagidae, Melanopareiidae and Tityridae. We find a remarkable difference in age of the initial divergence events in Furnariida and Tyrannida. The deepest branches in Furnariida are of Eocene age, whereas the extant lineages of Tyrannida have their origin in the Oligocene. Approximately half of the New World suboscine species are harboured in 5 large clades that started to diversify around the Mid Miocene Climatic Optimum (16-12 Mya). Based on our phylogenetic results we propose a revised classification of the New World suboscines. We also erect new family or subfamily level taxa for four small and isolated clades: Berlepschiinae, Pipritidae, Tachurididae and Muscigrallinae.
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24.
  • Ohlson, Jan I, et al. (författare)
  • Tyrant flycatchers coming out in the open: phylogeny and ecological radiation of Tyrannidae (Aves, Passeriformes)
  • 2008
  • Ingår i: Zoologica Scripta. - : Wiley. - 0300-3256 .- 1463-6409. ; 37:3, s. 315-335
  • Tidskriftsartikel (refereegranskat)abstract
    • Tyrant flycatchers constitute a substantial component of the land bird fauna in all South American habitats. Past interpretations of the morphological and ecological evolution in the group have been hampered by the lack of a well-resolved hypothesis of their phylogenetic interrelationships. Here, we present a well-resolved phylogeny based on DNA sequences from three nuclear introns for 128 taxa. Our results confirm much of the overall picture of Tyrannidae relationships, and also identify several novel relationships. The genera Onychorhynchus, Myiobius and Terenotriccus are placed outside Tyrannidae and may be more closely related to Tityridae. Tyrannidae consists of two main lineages. An expanded pipromorphine clade includes flatbills, tody-tyrants and antpipits, and also Phylloscartes and Pogonotriccus. The spadebills, Neopipo and Tachuris are their closest relatives. The remainder of the tyrant flycatchers forms a well-supported clade, subdivided in two large subclades, which differ consistently in foraging behaviour, the perch-gleaning elaeniines and the sallying myiarchines, tyrannines and fluvicolines. A third clade is formed by the genera Myiotriccus, Pyrrhomyias, Hirundinea and three species currently placed in Myiophobus. Ancestral habitat reconstruction and divergence date estimation suggest that early divergence events in Tyrannida took place in a humid forest environment during the Oligocene. Large-scale diversification in open habitats is confined to the clade consisting of the elaeniines, myiarchines, tyrannines and fluvicolines. This radiation correlates in time to the expansion of semi-open and open habitats from the mid-Miocene (c. 15 Mya) onwards. The pipromorphine, elaeniine and myiarchine–tyrannine–fluvicoline clades each employ distinct foraging strategies (upward striking, perch-gleaning and sallying, respectively), but the degree of diversity in morphology and microhabitat exploitation is markedly different between these clades. While the pipromorphines and elaeniines each are remarkably homogenous in morphology and exploit a restricted range of microhabitats, the myiarchine–tyrannine–fluvicoline clade is more diverse in these respects. This greater ecological diversity, especially as manifested in their success in colonizing a wider spectrum of open habitats, appears to be connected to a greater adaptive flexibility of the search-and-sally foraging behaviour.
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25.
  • Stervander, Martin, et al. (författare)
  • An updated chronology of passerine birds
  • 2020
  • Ingår i: <em>The Largest Avian Radiation</em>. - Barcelona : Lynx Edicions. ; , s. 387-396
  • Bokkapitel (övrigt vetenskapligt/konstnärligt)
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