TY - JOUR AB - Dispersal is crucial for gene flow and often determines the long-term stability of meta-populations, particularly in rare species with specialized life cycles. Such species are often foci of conservation efforts because they suffer disproportionally from degradation and fragmentation of their habitat. However, detailed knowledge of effective gene flow through dispersal is often missing, so that conservation strategies have to be based on mark-recapture observations that are suspected to be poor predictors of long-distance dispersal. These constraints have been especially severe in the study of butterfly populations, where microsatellite markers have been difficult to develop. We used eight microsatellite markers to analyse genetic population structure of the Large Blue butterfly Maculinea arion in Sweden. During recent decades, this species has become an icon of insect conservation after massive decline throughout Europe and extinction in Britain followed by reintroduction of a seed population from the Swedish island of Öland. We find that populations are highly structured genetically, but that gene flow occurs over distances 15 times longer than the maximum distance recorded from mark-recapture studies, which can only be explained by maximum dispersal distances at least twice as large as previously accepted. However, we also find evidence that gaps between sites with suitable habitat exceeding ∼ 20 km induce genetic erosion that can be detected from bottleneck analyses. Although further work is needed, our results suggest that M. arion can maintain fully functional metapopulations when they consist of optimal habitat patches that are no further apart than ∼10 km. AU - Ugelvig, Line V AU - Andersen, Anne AU - Boomsma, Jacobus AU - Nash, David ID - 3156 IS - 13 JF - Molecular Ecology TI - Dispersal and gene flow in the rare parasitic Large Blue butterfly Maculinea arion VL - 21 ER - TY - JOUR AB - We describe here the development and characterization of a conditionally inducible mouse model expressing Lifeact-GFP, a peptide that reports the dynamics of filamentous actin. We have used this model to study platelets, megakaryocytes and melanoblasts and we provide evidence that Lifeact-GFP is a useful reporter in these cell types ex vivo. In the case of platelets and megakaryocytes, these cells are not transfectable by traditional methods, so conditional activation of Lifeact allows the study of actin dynamics in these cells live. We studied melanoblasts in native skin explants from embryos, allowing the visualization of live actin dynamics during cytokinesis and migration. Our study revealed that melanoblasts lacking the small GTPase Rac1 show a delay in the formation of new pseudopodia following cytokinesis that accounts for the previously reported cytokinesis delay in these cells. Thus, through use of this mouse model, we were able to gain insights into the actin dynamics of cells that could only previously be studied using fixed specimens or following isolation from their native tissue environment. AU - Schachtner, Hannah AU - Li, Ang AU - Stevenson, David AU - Calaminus, Simon AU - Thomas, Steven AU - Watson, Steve AU - Sixt, Michael K AU - Wedlich Söldner, Roland AU - Strathdee, Douglas AU - Machesky, Laura ID - 3158 IS - 11-12 JF - European Journal of Cell Biology TI - Tissue inducible Lifeact expression allows visualization of actin dynamics in vivo and ex vivo VL - 91 ER - TY - JOUR AB - We describe RTblob, a high speed vision system that detects objects in cluttered scenes based on their color and shape at a speed of over 800 frames/s. Because the system is available as open-source software and relies only on off-the-shelf PC hardware components, it can provide the basis for multiple application scenarios. As an illustrative example, we show how RTblob can be used in a robotic table tennis scenario to estimate ball trajectories through 3D space simultaneously from four cameras images at a speed of 200 Hz. AU - Lampert, Christoph AU - Peters, Jan ID - 3248 IS - 1 JF - Journal of Real-Time Image Processing SN - 1861-8200 TI - Real-time detection of colored objects in multiple camera streams with off-the-shelf hardware components VL - 7 ER - TY - JOUR AB - The Brazilian Merganser is a very rare and threatened species that nowadays inhabits only a few protected areas and their surroundings in the Brazilian territory. In order to estimate the remaining genetic diversity and population structure in this species, two mitochondrial genes were sequenced in 39 individuals belonging to two populations and in one individual collected in Argentina in 1950. We found a highly significant divergence between two major remaining populations of Mergus octosetaceus, which suggests a historical population structure in this species. Furthermore, two deeply divergent lineages were found in a single location, which could due to current or historical secondary contact. Based on the available genetic data, we point out future directions which would contribute to design strategies for conservation and management of this threatened species. AU - Vilaça, Sibelle AU - Fernandes Redondo, Rodrigo A AU - Lins, Lívia AU - Santos, Fabrício ID - 3247 IS - 1 JF - Conservation Genetics TI - Remaining genetic diversity in Brazilian Merganser (Mergus octosetaceus) VL - 13 ER - TY - JOUR AB - How cells orchestrate their behavior during collective migration is a long-standing question. Using magnetic tweezers to apply mechanical stimuli to Xenopus mesendoderm cells, Weber etal. (2012) now reveal, in this issue of Developmental Cell, a cadherin-mediated mechanosensitive response that promotes cell polarization and movement persistence during the collective mesendoderm migration in gastrulation. AU - Behrndt, Martin AU - Heisenberg, Carl-Philipp J ID - 3245 IS - 1 JF - Developmental Cell TI - Spurred by resistance mechanosensation in collective migration VL - 22 ER -