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Explosive radiation in high Andean Hypericum - Rates of diversification among New World lineages

Title data

Nürk, Nicolai M. ; Scheriau, Charlotte ; Madriñán, Santiago:
Explosive radiation in high Andean Hypericum - Rates of diversification among New World lineages.
In: Frontiers in Genetics. (September 2013) . - No. 175.
ISSN 1664-8021
DOI: https://doi.org/10.3389/fgene.2013.00175

Abstract in another language

The páramos, high-elevation Andean grasslands ranging from ca. 2800 m to the snow line, harbor one of the fastest evolving biomes worldwide since their appearance in the northern Andes 3–5 million years (Ma) ago. Hypericum (St. John’s wort), with over 65% of its Neotropical species, has a center of diversity in these high Mountain ecosystems. Using nuclear rDNA internal transcribed spacer (ITS) sequences of a broad sample of New World Hypericum species we investigate phylogenetic patterns, estimate divergence times, and provide the first insights into diversification rates within the genus in the Neotropics. Two lineages appear to have independently dispersed into South America around 3.5 Ma ago, one of which has radiated in the páramos (Brathys). We find strong support for the polyphyly of section Trigynobrathys, several species of which group within Brathys, while others are found in temperate lowland South America (Trigynobrathys s.str.). All páramo species of Hypericum group in one clade. Within these páramo Hypericum species enormous phenotypic evolution has taken place (life forms from arborescent to prostrate shrubs) evidently in a short time frame. We hypothesize multiple mechanisms to be responsible for the low differentiation in the ITS region contrary to the high morphological diversity found in Hypericum in the páramos. Amongst these may be ongoing hybridization and incomplete lineage sorting, as well as the putative adaptive radiation, which can explain the contrast between phenotypic diversity and the close phylogenetic relationships.

Further data

Item Type: Article in a journal
Refereed: Yes
Additional notes: BAYCEER141640
Keywords: Adaptive radiation; Andes Mountains; rDNA ITS phylogenetics; Neotropics; Páramos; St. John's wort
Institutions of the University: Research Institutions
Research Institutions > Research Centres
Research Institutions > Research Centres > Bayreuth Center of Ecology and Environmental Research- BayCEER
Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Biology > Chair Plant Systematics
Faculties
Faculties > Faculty of Biology, Chemistry and Earth Sciences
Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Biology
Result of work at the UBT: Yes
DDC Subjects: 500 Science
Date Deposited: 25 Jan 2018 08:32
Last Modified: 25 Jan 2018 08:32
URI: https://eref.uni-bayreuth.de/id/eprint/41465