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Title Reconstruction of migration pathways of plants adapted to semiarid to arid regions in Southern Africa using molecular markers

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Short title Migration pathways of plants adapted to semiarid to arid regions

Author(s) Jürgens, N.; Oncken, I.; Rudolph, B.

Presenting author B. Rudolph

Institution(s) Biocenter Klein Flottbek, University of Hamburg

Keywords Southern Africa; semiarid to arid ecotone; phylogeography; Mesembryanthemum; molecular markers

Abstract The ecotone of winter and summer rainfall in the western part of Southern Africa (northern part of South Africa to Angola) houses a hotspot of endemic plants adapted to semiarid to arid regions. To understand the speciation processes of these species, as well as their phylogeographic patterns, we chose several key species within key centres to reconstruct their population structure, dynamics and migration pathways into, as well as within this area using molecular marker analyses. The plant species represent annual and biennial plants such as members of the Mesembryanthemoideae, but also perennial species with members of the genus Cheiridopsis to investigate recent radiation and speciation processes. The relic Welwitschia mirabilis was chosen to exemplify long-term processes. Leaf material of these species was collected along a north/ south transect with special emphasis to the BIOTA observatories.

One of these model species, representing annual/biennial species, is the Mesembryanthemum barklyi/ M. squamulosum complex. Though accumulating in microhabitats of heuweltjies the plants are distributed all-over the plain of the Richtersveld ecotone. This species complex is member of the Cryptophytum group of Mesembryanthemoideae (Aizoaceae), including M. crystallinum and M. guerichianum. The phylogeny of this complex could not be solved to date, though using multi gene sequencing analysis (Klak et al. 2007). To study the separation of this key species complex and to receive a more detailed picture of the speciation and radiation processes, we use a PCR marker system with a higher infraspecific resolution. Therefore we developed microsatellite markers. In this poster we present the first results of our genetic population analyses of this plant species complex.

Klak, C., Bruyns, P. V., Hedderson, T. A. J. 2007: A phylogeny and new classification for Mesembryanthemideae (Aizoaceae). Taxon 56: 737 - 756

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