Hirsch H.,Martin Luther University of Halle Wittenberg |
Zimmermann H.,Martin Luther University of Halle Wittenberg |
Ritz C.M.,Senckenberg Museum of Natural History Goerlitz |
Wissemann V.,Justus Liebig University |
And 6 more authors.
International Journal of Plant Sciences | Year: 2011
The exact geographic origin of invasive species populations is rarely known; however, such knowledge is vital to understanding species' invasion success, spread, and evolution as well as for assessing any biological control options. We investigated the shrub Rosa rubiginosa L., focusing on the presumed European origin of invasive populations in Argentina. We analyzed eight polymorphic microsatellite loci among 102 native (European) and 29 invasive (mainly central Argentinean and Patagonian) populations. Genetic diversity in the invasive range was clearly lower than in the native range, possibly because of a low number of introductions. Contrary to earlier hypotheses, the interpretation of principal coordinate analysis results and Jaccard dissimilarities contradicts the idea of the Argentinean populations having a Spanish origin. Instead, we found a close similarity between Argentinean samples and those from Germany, the Czech Republic, and Austria. We therefore assume that these neighboring countries are the most probable source regions for the Argentinean populations, which in some cases may also have arrived via Chile. According to historic information, emigrants from these regions may have introduced R. rubiginosa to South America in the nineteenth century on at least two occasions, either for food or as rootstock material for propagating living fences. © 2011 by The University of Chicago. All rights reserved.
Seeber E.,Senckenberg Museum of Natural History Goerlitz |
Winterfeld G.,Martin Luther University of Halle Wittenberg |
Hensen I.,Martin Luther University of Halle Wittenberg |
Hensen I.,German Center for Integrative Biodiversity Research iDiv Halle Jena Leipzig |
And 6 more authors.
Botanical Journal of the Linnean Society | Year: 2014
Polyploidy is a fundamental mechanism in evolution, but is hard to detect in taxa with agmatoploidy or aneuploidy. We tested whether a combination of chromosome counting, microsatellite analyses and flow cytometric measurements represents a suitable approach for the detection of basic chromosome numbers and ploidy in Kobresia (Cyperaceae). Chromosome counting resulted in 2n=64 for Kobresia pygmaea and K.cercostachys, 2n=58 and 64 for K.myosuroides, and 2n=72 for K.simpliciuscula. We characterized eight microsatellite loci for K.pygmaea, which gave a maximum of four alleles per individual. Cross-species amplification was tested in 26 congeneric species and, on average, six of eight loci amplified successfully. Using flow cytometry, we confirmed tetraploidy in K.pygmaea. Basic chromosome numbers and ploidy were inferred from chromosome counts and the maximum number of alleles per locus. We consider the basic numbers as x=16 and 18, with irregularities derived from agmatoploidy and aneuploidy. Across all Kobresia taxa, ploidy ranged from diploid up to heptaploid. The combination of chromosome counts and microsatellite analyses is an ideal method for the determination of basic chromosome numbers and for inferring ploidy, and flow cytometry is a suitable tool for the identification of deviating cytotypes. © 2014 The Linnean Society of London.
Abbott R.,University of St. Andrews |
Albach D.,Carl von Ossietzky University |
Ansell S.,Natural History Museum in London |
Arntzen J.W.,Netherlands Center for Biodiversity Naturalis |
And 36 more authors.
Journal of Evolutionary Biology | Year: 2013
Hybridization has many and varied impacts on the process of speciation. Hybridization may slow or reverse differentiation by allowing gene flow and recombination. It may accelerate speciation via adaptive introgression or cause near-instantaneous speciation by allopolyploidization. It may have multiple effects at different stages and in different spatial contexts within a single speciation event. We offer a perspective on the context and evolutionary significance of hybridization during speciation, highlighting issues of current interest and debate. In secondary contact zones, it is uncertain if barriers to gene flow will be strengthened or broken down due to recombination and gene flow. Theory and empirical evidence suggest the latter is more likely, except within and around strongly selected genomic regions. Hybridization may contribute to speciation through the formation of new hybrid taxa, whereas introgression of a few loci may promote adaptive divergence and so facilitate speciation. Gene regulatory networks, epigenetic effects and the evolution of selfish genetic material in the genome suggest that the Dobzhansky-Muller model of hybrid incompatibilities requires a broader interpretation. Finally, although the incidence of reinforcement remains uncertain, this and other interactions in areas of sympatry may have knock-on effects on speciation both within and outside regions of hybridization. © 2013 European Society For Evolutionary Biology.
Mucci N.,European Commission - Joint Research Center Ispra |
Arrendal J.,Uppsala University |
Ansorge H.,Senckenberg Museum of Natural History Goerlitz |
Bailey M.,Trinity College Dublin |
And 36 more authors.
Conservation Genetics | Year: 2010
Eurasian otter populations strongly declined and partially disappeared due to global and local causes (habitat destruction, water pollution, human persecution) in parts of their continental range. Conservation strategies, based on reintroduction projects or restoration of dispersal corridors, should rely on sound knowledge of the historical or recent consequences of population genetic structuring. Here we present the results of a survey performed on 616 samples, collected from 19 European countries, genotyped at the mtDNA control-region and 11 autosomal microsatellites. The mtDNA variability was low (nucleotide diversity = 0.0014; average number of pairwise differences = 2.25), suggesting that extant otter mtDNA lineages originated recently. A star-shaped mtDNA network did not allow outlining any phylogeographic inference. Microsatellites were only moderately variable (Ho = 0.50; He = 0.58, on average across populations), the average allele number was low (observed Ao = 4.9, range 2.5-6.8; effective Ae = 2.8; range 1.6-3.7), suggesting small historical effective population size. Extant otters likely originated from the expansion of a single refugial population. Bayesian clustering and landscape genetic analyses however indicate that local populations are genetically differentiated, perhaps as consequence of post-glacial demographic fluctuations and recent isolation. These results delineate a framework that should be used for implementing conservation programs in Europe, particularly if they are based on the reintroduction of wild or captive-reproduced otters. © 2010 Springer Science+Business Media B.V.