| 1. |
- Escudero, Marcial, et al.
(författare)
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Karyotypic Changes through Dysploidy Persist Longer over Evolutionary Time than Polyploid Changes
- 2014
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 9:1, s. e85266-
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Tidskriftsartikel (refereegranskat)abstract
- Chromosome evolution has been demonstrated to have profound effects on diversification rates and speciation in angiosperms. While polyploidy has predated some major radiations in plants, it has also been related to decreased diversification rates. There has been comparatively little attention to the evolutionary role of gains and losses of single chromosomes, which may or not entail changes in the DNA content (then called aneuploidy or dysploidy, respectively). In this study we investigate the role of chromosome number transitions and of possible associated genome size changes in angiosperm evolution. We model the tempo and mode of chromosome number evolution and its possible correlation with patterns of cladogenesis in 15 angiosperm clades. Inferred polyploid transitions are distributed more frequently towards recent times than single chromosome gains and losses. This is likely because the latter events do not entail changes in DNA content and are probably due to fission or fusion events (dysploidy), as revealed by an analysis of the relationship between genome size and chromosome number. Our results support the general pattern that recently originated polyploids fail to persist, and suggest that dysploidy may have comparatively longer-term persistence than polyploidy. Changes in chromosome number associated with dysploidy were typically observed across the phylogenies based on a chi-square analysis, consistent with these changes being neutral with respect to diversification.
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| 2. |
- Fiz-Palacios, Omar, et al.
(författare)
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From Messinian crisis to Mediterranean climate : A temporal gap of diversification recovered from multiple plant phylogenies
- 2013
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Ingår i: Perspectives in plant ecology, evolution and systematics. - : Elsevier BV. - 1433-8319 .- 1618-0437. ; 15:2, s. 130-137
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Tidskriftsartikel (refereegranskat)abstract
- Paleobotanical and molecular studies link diversification of plants in the Mediterranean Basin with the onset of the Mediterranean climate. Screening diversification before this period is needed in order to analyze whether the observed increase in diversification is a legitimate footprint denoting radiation or instead the biological signal of a previous mass extinction or rate stasis period. A shared post-Messinian temporal gap of cladogenesis has been previously observed in two Mediterranean sister genera. Based on this evidence we explored recently published molecular studies to recover lineages with similar diversification profiles exhibiting a cladogenesis gap. Using this criterion, we conducted a meta-analysis of 36 Mediterranean plant lineages with a post-Messinian temporal gap of cladogenesis, including a new molecular dating of Genista (Fabaceae). Whereas 39% of these lineages have not diversified since the Miocene, another 39% began to rediversify during the onset of the Mediterranean climate and the remaining 22% began diversifying again afterwards during the Quaternary. The pattern of Mediterranean diversification recovery after a temporal gap of cladogenesis was also obtained with phylogenetic tree simulations under birth and death processes when forcing one or two temporal shifts in diversification rates. The relative importance of the Mediterranean onset as a driving force promoting speciation or triggering extinction remains as an open question, since neither the mass extinction nor the rate stasis evolutionary scenarios can be rule out. The independent analysis of individual clades within phylogenies is also essential to detect clade-dependent patterns hidden by phylogeny-level ones. We disclose the importance of analyzing diversification patterns of Mediterranean lineages since the Miocene to understand the recent history of the Mediterranean biota.
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| 3. |
- Fiz-Palacios, Omar, et al.
(författare)
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Imbalanced diversification of two Mediterranean sister genera (Bellis and Bellium, Asteraceae) within the same time frame
- 2011
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Ingår i: Plant Systematics and Evolution. - : Springer Science and Business Media LLC. - 0378-2697 .- 1615-6110. ; 295:1-4, s. 109-118
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Tidskriftsartikel (refereegranskat)abstract
- The Daisies, Bellis and Bellium, form a monophyletic complex within the core Astereae (Asteraceae). Although most early diverging lineages show an African distribution, the core Astereae is today widespread on five continents with the Bellis/Bellium complex as the only representative in the Mediterranean basin. Molecular clock estimates placed the divergence of Astereae from its sister tribe Anthemideae in the Oligocene. Using a combination of three plastid genes, we estimated divergence times for different lineages of the tribe Astereae. This, together with temporal and biogeographical reconstructions using the nrITS region, allows placing and timing of the major lineages of the Bellis/Bellium complex. The age reconstruction places the divergence of the tribe Astereae in the late Miocene (18-19 million years ago), followed by an out-of-Africa dispersal into Asia where the worldwide expansion may have started. Our results suggest that the colonization of the Mediterranean basin by the Astereae started from Eurasia some 10 million years ago. A Messinian early divergence of the Bellis/Bellium complex in the Mediterranean was estimated. However, a parallel 4-million-year delay for the within-genera diversification was inferred, probably related to the establishment of the sclerophyllous Mediterranean forest. Despite a similar time frame for the within-genera diversification, today's species numbers differ considerably between Bellis (15 spp.) and Bellium (five spp.).
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| 4. |
- Valcarcel, Virginia, et al.
(författare)
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The origin of the early differentiation of Ivies (Hedera L.) and the radiation of the Asian Palmate group (Araliaceae)
- 2014
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Ingår i: Molecular Phylogenetics and Evolution. - : Elsevier BV. - 1055-7903 .- 1095-9513. ; 70, s. 492-503
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Tidskriftsartikel (refereegranskat)abstract
- The Asian Palmate group is one of the four major clades of the family Araliaceae that is formed by 18 genera, including ivies (Hedera L.). The Mediterranean diversity centre and temperate affinity of ivies contrast with the inferred Asian centre of diversity of the primarily tropical and subtropical Asian Palmate group. We herein investigated the sister-group relationships of Hedera to reconstruct the evolutionary context for its origin and early diversification. Seven nuclear and plastid DNA regions were analyzed in 61 Araliaceae samples including all the 18 Asian Palmate genera. Maximum Parsimony, Maximum Likelihood and Bayesian Inference were run together with a battery of topology testing analyses constraining the expected Hedera's sister-group relationships. Additionally. Bayesian polytomy resolvability and divergence time analyses were also conducted. Genome incongruence and hard nuclear and plastid basal polytomies are detected for the Asian Palmate group where the lineage of Hedera is placed. Topology testing analyses do not allow rejecting any of the tentative sisters of Hedera. An early radiation with inter-lineage hybridization and genome doubling is suggested for the Asian Palmate group where all the seven temperate genera, including Hedera, seem to have played an important role. The radiation took placed during the Upper Cretaceous in Asia under a general cooling and the eastern Asian mountain uplift that produced new temperate environments and promoted lineage connections. This allows us to hypothesize that the origin of the Hedera lineage may fit in a temperate niche conservatism scenario where the combination of the radiation with lineage admixtures prevents us from discovering its sister-group.
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