Adaptive evolution of hybrid bacteria by horizontal gene transfer

Horizontal gene transfer is an important factor in bacterial evolution that can act across species boundaries. Yet, we know little about rate and genomic targets of cross-lineage gene transfer, and about its effects on the recipient organism's physiology and fitness. Here, we address these questions in a parallel evolution experiment with two Bacillus subtilis lineages of 7% sequence divergence. We observe rapid evolution of hybrid organisms: gene transfer swaps ~12% of the core genome in just 200 generations, and 60% of core genes are replaced in at least one population. By genomics, transcriptomics, fitness assays, and statistical modeling, we show that transfer generates adaptive evolution and functional alterations in hybrids. Specifically, our experiments reveal a strong, repeatable fitness increase of evolved populations in the stationary growth phase. By genomic analysis of the transfer statistics across replicate populations, we infer that selection on HGT has a broad genetic basis: 40% of the observed transfers are adaptive. At the level of functional gene networks, we find signatures of negative and positive selection, consistent with hybrid incompatibilities and adaptive evolution of network functions. Our results suggest that gene transfer navigates a complex cross-lineage fitness landscape, bridging epistatic barriers along multiple high-fitness paths.Comment: The first three authors are joint first authors. Corresponding authors are Lassig and Maie

German history-digital: A platform for transnational historical knowledge co-creation

The German Historical Institute Washington (GHI) is in the development phase of German History Digital (GH-D), a transatlantic digital initiative to meet the scholarly needs of historians and their students facing new historiographical and technological challenges. In the proposed paper we will discuss the research goals, methodology, prototyping, and development strategy of GH-D as infrastructure to facilitate transnational historical knowledge co-creation for the large community of researchers and students already relying on digital resources of the GHI and for the growing constituency of citizen scholars

Sozialökonomischer Wandel - Politische Stagnation: Das Deutsche Kaiserreich am Vorabend des Ersten Weltkriegs

Wehler H-U. Sozialökonomischer Wandel - Politische Stagnation: Das Deutsche Kaiserreich am Vorabend des Ersten Weltkriegs. In: Lässig S, Pohl KH, eds. Sachsen im Kaiserreich. Weimar: Böhlau; 1997: 301-308

Predictive Modeling of Influenza Shows the Promise of Applied Evolutionary Biology

Seasonal influenza is controlled through vaccination campaigns. Evolution of influenza virus antigens means that vaccines must be updated to match novel strains, and vaccine effectiveness depends on the ability of scientists to predict nearly a year in advance which influenza variants will dominate in upcoming seasons. In this review, we highlight a promising new surveillance tool: predictive models. Developed through data-sharing and close collaboration between the World Health Organization and academic scientists, these models use surveillance data to make quantitative predictions regarding influenza evolution. Predictive models demonstrate the potential of applied evolutionary biology to improve public health and disease control. We review the state of influenza predictive modeling and discuss next steps and recommendations to ensure that these models deliver upon their considerable biomedical promise

Invited

The aim of this program is to bring together researchers and students from different backgrounds (including molecular biology, bioinformatics, biological physics) to discuss a topic of high current interest. We plan an integrated program, which is focused on high-level training during the first days and leads to topical research seminars in the second part. The schedule will leave sufficient time for discussion and interaction among students and lectures