| 1. |
- Blanco-Gavaldà, Carme, et al.
(författare)
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Repeatedly Northwards and Upwards: Southern African Grasslands Fuel the Colonization of the African Sky Islands in Helichrysum (Compositae)
- 2023
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Ingår i: Plants. ; 12:2213, s. 1-24
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Tidskriftsartikel (refereegranskat)abstract
- The Afromontane and Afroalpine areas constitute some of the main biodiversity hotspots of Africa. They are particularly rich in plant endemics, but the biogeographic origins and evolutionary processes leading to this outstanding diversity are poorly understood. We performed phylogenomic and biogeographic analyses of one of the most species-rich plant genera in these mountains, Helichrysum (Compositae-Gnaphalieae). Most previous studies have focused on Afroalpine elements of Eurasian origin, and the southern African origin of Helichrysum provides an interesting counterexample. We obtained a comprehensive nuclear dataset from 304 species ( 50% of the genus) using target-enrichment with the Compositae1061 probe set. Summary-coalescent and concatenation approaches combined with paralog recovery yielded congruent, well-resolved phylogenies. Ancestral range estimations revealed that Helichrysum originated in arid southern Africa, whereas the southern African grasslands were the source of most lineages that dispersed within and outside Africa. Colonization of the tropical Afromontane and Afroalpine areas occurred repeatedly throughout the Miocene–Pliocene. This timing coincides with mountain uplift and the onset of glacial cycles, which together may have facilitated both speciation and intermountain gene flow, contributing to the evolution of the Afroalpine flora.
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| 2. |
- Lewin, Harris A., et al.
(författare)
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The Earth BioGenome Project 2020 : Starting the clock
- 2022
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences (PNAS). - 0027-8424 .- 1091-6490. ; 119:4
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 3. |
- Roquet, Cristina, et al.
(författare)
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Reconstructing the history of Campanulaceae with a Bayesian approach to molecular dating and dispersal-vicariance analyses
- 2009
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Ingår i: Molecular Phylogenetics and Evolution. - : Elsevier BV. - 1055-7903 .- 1095-9513. ; 52:3, s. 575-587
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Forskningsöversikt (refereegranskat)abstract
- We reconstruct here the spatial and temporal evolution of the Campanula alliance in order to better understand its evolutionary history. To increase phylogenetic resolution among major groups (Wahlenbergieae-Campanuleae), new sequences from the rbcL region were added to the trnL-F dataset obtained in a previous Study. These phylogenies were used to infer ancestral areas and divergence times in Campanula and related genera using a Bayesian approach to molecular dating and dispersal-vicariance analyses that takes into account phylogenetic uncertainty. The new phylogenetic analysis confirms Platycodoneae as the sister group of Wahlenbergieae-Campanuleae, the two last ones inter-graded into a well-supported clade. Biogeographic and dating analyses suggest that Western Asia and the Eastern Mediterranean have played a major role as centers of migration and diversification within the Campanula alliance, probably in relation to the intense orogenic activity that took place in this region during the Late Neogene, and that could have promoted isolation and allopatric speciation within lineages. Diversification rates within several Campanula lineages would have increased at the end of the Miocene, coinciding with the Messinian Stage. Strong selective pressures from climate changes and the expansion of mountainous regions during this period are suggested to explain the adaptation to drought, cold or disturbed environments observed in many Campanula species. Several independent long-distance dispersal events to North America are inferred within the Ropunculus clade, which seem to be related to high ploidy levels.
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