Achigan-Dako, Enoch G. , Blattner, Frank R. .
Phylogeography, phylogeny, and ecoclimatic niche modelling in West African Momordica charantia (Cucurbitaceae): differentiation across ecological gradients.
Recently, Momordica charantia, a paleotropical species used as vegetable or medicinal resource, was split into two different subspecies (ssp. charantia and macroloba) due to morphological differences. Subspecies macroloba occurs in a restricted area within the widespread ssp. charantia. To understand their phylogenetic relationships and to estimate geneflow between both taxa we conducted an AFLP study using eight primer combinations and 90 accessions from West Africa. We used population genetic, phylogeographic and phylogenetic analysis approaches combined with ecoclimatic niche modeling.
Our results show that within the species two clearly separated monophyletic genepools exist. These are (i) the individuals from the semiarid Sahel zone vs. (ii) all other populations occurring in the wetter forest and savannah habitats towards the south. Within the latter group ssp. macroloba is a monophyletic unit within ssp. charantia. Geneflow between both taxa is low although they occur partly in the same area. The analysis also indicated the existence of a forest ecotype, as all individuals collected in the evergreen forest of Ghana cluster together, while populations from the Sudano-Guinean and Dahomey gap area were widespread throughout the phylogenetic trees. Ecoclimatic niche modeling predicted different distribution areas for both subspecies, thus indicating that ecological differences already exist. Although ITS sequencing did not reveal any difference among all populations, for the individuals of the semiarid north even species status might be proposed, as they are sister group to the other M. charantia populations, geographically and ecologically isolated, and no geneflow seem to occur between both groups.
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1 - Institute of Plant Genetics and Crop Research (IPK), Taxonomy & Evol. Biology, Gatersleben, D-06466, Germany
Presentation Type: Oral Paper:Papers for Topics
Date: Monday, July 28th, 2008
Time: 1:45 PM