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- Leebens-Mack, James H., et al.
(författare)
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One thousand plant transcriptomes and the phylogenomics of green plants
- 2019
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Ingår i: Nature. - : Nature Publishing Group. - 0028-0836 .- 1476-4687. ; 574:7780, s. 679-
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Tidskriftsartikel (refereegranskat)abstract
- Green plants (Viridiplantae) include around 450,000-500,000 species(1,2) of great diversity and have important roles in terrestrial and aquatic ecosystems. Here, as part of the One Thousand Plant Transcriptomes Initiative, we sequenced the vegetative transcriptomes of 1,124 species that span the diversity of plants in a broad sense (Archaeplastida), including green plants (Viridiplantae), glaucophytes (Glaucophyta) and red algae (Rhodophyta). Our analysis provides a robust phylogenomic framework for examining the evolution of green plants. Most inferred species relationships are well supported across multiple species tree and supermatrix analyses, but discordance among plastid and nuclear gene trees at a few important nodes highlights the complexity of plant genome evolution, including polyploidy, periods of rapid speciation, and extinction. Incomplete sorting of ancestral variation, polyploidization and massive expansions of gene families punctuate the evolutionary history of green plants. Notably, we find that large expansions of gene families preceded the origins of green plants, land plants and vascular plants, whereas whole-genome duplications are inferred to have occurred repeatedly throughout the evolution of flowering plants and ferns. The increasing availability of high-quality plant genome sequences and advances in functional genomics are enabling research on genome evolution across the green tree of life.
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| 2. |
- Pedersen, Henrik AE., et al.
(författare)
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Phylogenetics of Dendrochilum (Orchidaceae) : Evidence of pronounced morphological homoplasy and predominantly centric endemism
- 2019
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Ingår i: Taxon. - : John Wiley & Sons. - 0040-0262 .- 1996-8175. ; 68:6, s. 1173-1188
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Tidskriftsartikel (refereegranskat)abstract
- A phylogenetic hypothesis for the genus Dendrochilum s.l. (including Bracisepalum) is based on nucleotide sequences of the nuclear ribosomal ITS and two plastid regions (matK, ycf1). The trees based on parsimony analysis of the nrITS and plastid partitions, respectively, are largely congruent, the only strongly supported conflict being the exact position of D. arachnites. Maximum likelihood analysis of the combined molecular matrix resulted in a tree with very high topological congruence to the parsimony consensus tree and to a fossil-calibrated Bayesian inference tree that was used for dating. Our results confirm that monophyly of Dendrochilum is only supported if Bracisepalum is included in the former. They also suggest that only two subgenera (Dendrochilum, Platyclinis) should be recognized, whereas all other subgenera and sections previously proposed on a morphological basis should be treated as synonyms of subg. Platyclinis. Indeed, mapping of five vegetative and nine floral characters of alleged systematic value, using DELTRAN and ACCTRAN optimization, demonstrates pronounced morphological homoplasy. Molecular time calibration dates the origin of the genus to the Miocene and contradicts the hypothesis that most extant Dendrochilum species did not evolve until the Holocene. Inferred phylogenetic relationships between extant species, in combination with previously identified hotspots of narrow endemism, suggest that species endemism in Dendrochilum is predominantly centric.
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