Molecular Ecology and Evolution
von Hagen, K. Bernhard , Blattner, Frank R. .
Molecular and morphological evidence for cryptic speciation and paralell selection in Central American Halenia decumbens (Gentianaceae).
WE recently have shown that a group of Halenia species from South America differs significantly in the diversification rate from Halenia decumbens which is probably the single Central American sisterspecies. To further study this difference we now have analysed the chloroplast diversity of 15 populations (c. 100 individuals) of the latter species using chloroplast trnT-L sequences and additionally selected nuclear ITS and chloroplast rpl16 intron sequences. We also studied the variability of different vegetative and flower morphological traits on c. 100 individuals from South and Central America. We have found evidence for chloroplast capture and some hybridisation going on in Central America which complicates the results and interpretations. Nevertheless, when these difficulties are left from consideration we most importantly have found that H. decumbens is paraphyletic in relation to the South American group. However, the multivariate morphological analysis resulted in a well defined and much less variable H. decumbens in comparison with the South American species. In summary, this could be interpreted as evidence for cryptic speciation in Central America. This difference bewteen neutral and selected markers probably shows that the morphological identity of H. decumbens has been maintained by parallel selection and not by any measurable geneflow since its first separation into different populations and the southern populations have given rise to several new species probably facing a more divergent selection regime in South America.
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1 - Martin-Luther-University Halle-Wittenberg, Institute for Geobotany, Neuwerk 21, Halle, 06114, Germany
2 - Inst. of Plant Genetics and Crop Plant Research, Dept. of Taxonomy, Corrensstr. 3, Gatersleben, D-06466, Germany
Presentation Type: Oral Paper:Papers for Topics
Date: Monday, July 31st, 2006
Time: 4:15 PM