| 1. |
- Perez-Escobar, Oscar A., et al.
(författare)
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The origin and speciation of orchids
- 2024
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Ingår i: NEW PHYTOLOGIST. - 0028-646X .- 1469-8137.
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Tidskriftsartikel (refereegranskat)abstract
- Orchids constitute one of the most spectacular radiations of flowering plants. However, their origin, spread across the globe, and hotspots of speciation remain uncertain due to the lack of an up-to-date phylogeographic analysis. We present a new Orchidaceae phylogeny based on combined high-throughput and Sanger sequencing data, covering all five subfamilies, 17/22 tribes, 40/49 subtribes, 285/736 genera, and c. 7% (1921) of the 29 524 accepted species, and use it to infer geographic range evolution, diversity, and speciation patterns by adding curated geographical distributions from the World Checklist of Vascular Plants. The orchids' most recent common ancestor is inferred to have lived in Late Cretaceous Laurasia. The modern range of Apostasioideae, which comprises two genera with 16 species from India to northern Australia, is interpreted as relictual, similar to that of numerous other groups that went extinct at higher latitudes following the global climate cooling during the Oligocene. Despite their ancient origin, modern orchid species diversity mainly originated over the last 5 Ma, with the highest speciation rates in Panama and Costa Rica. These results alter our understanding of the geographic origin of orchids, previously proposed as Australian, and pinpoint Central America as a region of recent, explosive speciation.
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| 2. |
- de Boer, Hugo J., 1978-, et al.
(författare)
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Evolution and loss of long-fringed petals : A case study using a dated phylogeny of the snake gourds, Trichosanthes (Cucurbitaceae)
- 2012
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Ingår i: BMC Evolutionary Biology. - : Springer Science and Business Media LLC. - 1471-2148. ; 12, s. 108-
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundThe Cucurbitaceae genus Trichosanthes comprises 90–100 species that occur from India to Japan and southeast to Australia and Fiji. Most species have large white or pale yellow petals with conspicuously fringed margins, the fringes sometimes several cm long. Pollination is usually by hawkmoths. Previous molecular data for a small number of species suggested that a monophyletic Trichosanthes might include the Asian genera Gymnopetalum (four species, lacking long petal fringes) and Hodgsonia (two species with petals fringed). Here we test these groups’ relationships using a species sampling of c. 60% and 4759 nucleotides of nuclear and plastid DNA. To infer the time and direction of the geographic expansion of the Trichosanthes clade we employ molecular clock dating and statistical biogeographic reconstruction, and we also address the gain or loss of petal fringes.ResultsTrichosanthes is monophyletic as long as it includes Gymnopetalum, which itself is polyphyletic. The closest relative of Trichosanthes appears to be the sponge gourds, Luffa, while Hodgsonia is more distantly related. Of six morphology-based sections in Trichosanthes with more than one species, three are supported by the molecular results; two new sections appear warranted. Molecular dating and biogeographic analyses suggest an Oligocene origin of Trichosanthes in Eurasia or East Asia, followed by diversification and spread throughout the Malesian biogeographic region and into the Australian continent.ConclusionsLong-fringed corollas evolved independently in Hodgsonia and Trichosanthes, followed by two losses in the latter coincident with shifts to other pollinators but not with long-distance dispersal events. Together with the Caribbean Linnaeosicyos, the Madagascan Ampelosicyos and the tropical African Telfairia, these cucurbit lineages represent an ideal system for more detailed studies of the evolution and function of petal fringes in plant-pollinator mutualisms.
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| 3. |
- Denk, Thomas, et al.
(författare)
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Plant fossils reveal major biomes occupied by the late Miocene Old-World Pikermian fauna
- 2018
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Ingår i: Nature Ecology & Evolution. - London : Nature Publishing Group. - 2397-334X. ; 2, s. 1864-1870
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Tidskriftsartikel (refereegranskat)abstract
- Reconstruction of palaeobiomes, ancient communities that exhibit a physiognomic and functional structure controlled by their environment, depends on proxies from different disciplines. Based on terrestrial mammal fossils, the late Miocene vegetation from China to the eastern Mediterranean and East Africa has been reconstructed as a single cohesive biome with increasingly arid conditions, with modern African savannahs the surviving remnant. Here, we test this reconstruction using plant fossils spanning 14–4 million years ago from sites in Greece, Bulgaria, Turkey, the Tian Shan Mountains and Baode County in China, and East Africa. The western Eurasian sites had a continuous forest cover of deciduous or evergreen angiosperms and gymnosperms, with 15% of 1,602 fossil occurrences representing conifers, which were present at all but one of the sites. Raup–Crick analyses reveal high floristic similarity between coeval eastern Mediterranean and Chinese sites, and low similarity between Eurasian and African sites. The disagreement between plant-based reconstructions, which imply that late Miocene western Eurasia was covered by evergreen needleleaf forests and mixed forests, and mammal-based reconstructions, which imply a savannah biome, throws into doubt the approach of inferring Miocene precipitation and open savannah habitats solely from mammalian dental traits. Organismal communities are constantly changing in their species composition, and neither animal nor plant traits by themselves are sufficient to infer entire ancient biomes. The plant fossil record, however, unambiguously rejects the existence of a cohesive savannah biome from eastern Asia to northeast Africa.
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| 4. |
- Ickert-Bond, Stefanie M., et al.
(författare)
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A fossil-calibrated relaxed clock for Ephedra indicates an Oligocene age for the divergence of Asian and New World clades and Miocene dispersal into South America
- 2009
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Ingår i: Journal of Systematics and Evolution. - : Wiley. - 1674-4918 .- 1759-6831. ; 47:5, s. 444-456
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Tidskriftsartikel (refereegranskat)abstract
- Ephedra comprises approximately 50 species, which are roughly equally distributed between the Old and New World deserts, but not in the intervening regions (amphitropical range). Great heterogeneity in the substitution rates of Gnetales (Ephedra, Gnetum, and Welwitschia) has made it difficult to infer the ages of the major divergence events in Ephedra, such as the timing of the Beringian disjunction in the genus and the entry into South America. Here, we use data from as many Gnetales species and genes as available from GenBank and from a recent study to investigate the timing of the major divergence events. Because of the tradeoff between the amount of missing data and taxon/gene sampling, we reduced the initial matrix of 265 accessions and 12 loci to 95 accessions and 10 loci, and further to 42 species (and 7736 aligned nucleotides) to achieve stationary distributions in the Bayesian molecular clock runs. Results from a relaxed clock with an uncorrelated rates model and fossil‐based calibration reveal that New World species are monophyletic and diverged from their mostly Asian sister clade some 30 mya, fitting with many other Beringian disjunctions. The split between the single North American and the single South American clade occurred approximately 25 mya, well before the closure of the Panamanian Isthmus. Overall, the biogeographic history of Ephedra appears dominated by long‐distance dispersal, but finer‐scale studies are needed to test this hypothesis.
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| 5. |
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| 6. |
- Solaki, Maria, et al.
(författare)
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Comprehensive variant spectrum of the CNGA3 gene in patients affected by achromatopsia
- 2022
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Ingår i: Human Mutation. - : John Wiley & Sons. - 1059-7794 .- 1098-1004. ; 43:7, s. 832-858
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Tidskriftsartikel (refereegranskat)abstract
- Achromatopsia (ACHM) is a congenital cone photoreceptor disorder characterized by impaired color discrimination, low visual acuity, photosensitivity, and nystagmus. To date, six genes have been associated with ACHM (CNGA3, CNGB3, GNAT2, PDE6C, PDE6H, and ATF6), the majority of these being implicated in the cone phototransduction cascade. CNGA3 encodes the CNGA3 subunit of the cyclic nucleotide-gated ion channel in cone photoreceptors and is one of the major disease-associated genes for ACHM. Herein, we provide a comprehensive overview of the CNGA3 variant spectrum in a cohort of 1060 genetically confirmed ACHM patients, 385 (36.3%) of these carrying “likely disease-causing” variants in CNGA3. Compiling our own genetic data with those reported in the literature and in public databases, we further extend the CNGA3 variant spectrum to a total of 316 variants, 244 of which we interpreted as “likely disease-causing” according to ACMG/AMP criteria. We report 48 novel “likely disease-causing” variants, 24 of which are missense substitutions underlining the predominant role of this mutation class in the CNGA3 variant spectrum. In addition, we provide extensive in silico analyses and summarize reported functional data of previously analyzed missense, nonsense and splicing variants to further advance the pathogenicity assessment of the identified variants.
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| 7. |
- Zani, Deborah, et al.
(författare)
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Response to comment on "increased growing-season productivity drives earlier autumn leaf senescence in temperate trees
- 2021
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 371:6533
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Forskningsöversikt (refereegranskat)abstract
- Our study showed that increases in seasonal productivity drive earlier autumn senescence of temperate trees. Norby argues that this finding is contradicted by observations from free-air CO2 enrichment (FACE) experiments, where elevated CO2 has been found to delay senescence in some cases. We provide a detailed answer showing that the results from FACE studies are in agreement with our conclusions.
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