Abstracts - Deutsche Zoologische Gesellschaft

Evolutionary Biology Posters 125P EB.1 - ENTracking a biogeographical paradox: the microgastropod genus Heleobia (Rissooidea:Cochliopidae) in South America and EuropeChristian Albrecht, Oliver Kroll, Thomas WilkeSpezielle Zoologie und Biodiversitätsforschung, Justus-Liebig-Universität, GießenThe strongly disjunct distribution of Heleobia (occurring in South America and Europe) has puzzledbiologists for decades. The type species lives in Lake Titicaca, together with 13 other endemicHeleobia taxa.Based on sequence data from 11 Heleobia species from Lake Titicaca and severalother taxa from South America and Europe, we aimed at investigating: 1) the phylogenetic positionof Heleobia, 2) the amphiatlantic relationship of Heleobia spp., and 3) whether the Lake Titicacaspecies represent a species flock.The analyses showed that the genus is not monophyletic. Heleobias.s. appears to be restricted to Lake Titicaca. Its sister is the nominal European subgenus Semisalsa.One Italian taxon, S. aponensis, does not belong to this subgenus. Thus, the faunal exchangebetween South America and Europe must have happened at least twice.Concerning Lake TiticacaHeleobia, it fulfills the criteria of an ancient lake species flock. Preliminary molecular clock analysesindicate that the radiation is very young. Moreover, none of the nominal species can be separated ina COI maximum parsimony network. Morphological analyses show a high degree of shell structuring.However, in many taxa, we could find independent transitions between these character states.Future studies have to show whether the Titicaca complex: 1) comprises only a single or few species,2) is a case of incomplete lineage sorting, or 3) constitutes a group of species that are subjectto phenotypical plasticity.P EB.2 - ENBalancing selection on cis-regulatory variation at B4galnt2 and its influence on vonWillebrand Factor in house miceJohn Baines 1 , Jill Johnsen 2 , Meike Teschke 3 , Diethard Tautz 3 , David Ginsburg 41Department of Evolutionary Biology, University of Munich; 2 Puget Sound Blood Center andDepartment of Internal Medicine, University of Washington, Seattle, USA; 3 Max Planck Institutefor Evolutionary Biology, Plön; 4 Department of Internal Medicine, Howard Hughes Medical Institute,Department of Human Genetics, and the Life Sciences Institute, University of Michigan, AnnArbor, USAMammals tolerate wide variation in the critical clotting protein, von Willebrand Factor (VWF).The RIIIS/J laboratory mouse strain carries a mutation that switches the pattern of expression of aglycosyltransferase, B4galnt2, from intestine to blood vessels, resulting in low VWF levels similarto a common human bleeding disorder, von Willebrand Disease (VWD). We surveyed wild mousepopulations for DNA sequence and microsatellite variability, B4galnt2 expression pattern, and VWFlevel. We found that the RIIIS/J haplotype is present in wild mouse populations at varying frequencies.Strikingly, wild mice carrying an RIIIS/J haplotype display VWF levels less than half those ofmice that do not. Analysis of microsatellite and DNA sequence variation surrounding the B4galnt2gene found evidence of both recent natural selection and more long-term balancing selection, implyingthat intermittent selection may have maintained the RIIIS/J haplotype over a long evolutionarytime period. We hypothesize that mice tolerate low VWF levels in exchange for another benefit ofaltered expression of the glycosyltransferase. Similar mechanisms may account for the tolerance ofvariation of VWF and high prevalence of VWD in other mammals, including humans.