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

Myxoma of the Middle Ear Mimicking Chronic Otitis Media

Myxoma is a benign connective tissue tumor that arises mostly from the heart. Temporal bone myxomas are extremely rare and these patients should be evaluated for the Carney complex association. Herein, our aim was to present a middle ear myxoma case operated with an initial diagnosis of chronic otitis media (COM) and to underline the fact that myxomas should be kept in mind in the differential diagnosis of aural polyps

Team 10 tasarım stratejilerinin günümüzdeki önemi

This thesis aims at understanding design strategies developed by Team 10 members and their relevance to contemporary architecture. These strategies are studied by referring to their seminal projects. It is argued that what is significant in the design approaches of Team 10 is the search for patterns of human association or networks of human relations that supports physical structure and organizes social communication. The thesis focuses on the Golden Lane Housing Project (1952) by Alison and Peter Smithson is in order to illustrate how the patterns of association are organized. Team 10̕s approach to design suggests a shift of emphasis from specific object to spatial organization of relations. They try to achieve a multi-layered urban and architectural solution. Their projects are infrastructural organizations, in which all layers are combined in a perpetual complex system. The thesis makes an analysis of the Golden Lane Housing Project in order to understand the ways how the layers are organized and associated to each other. An inquiry into the works of Team 10 members shows that they put particular emphasis on the notions of infrastructural organization, mobility, flexibility, layering, adaptability to change and growth, repetition and variation. The thesis points out that these notions are still relevant in contemporary architectural practices.M.Arch. - Master of Architectur

Ritz Yöntemi Kullanılarak İntegral Operatörlerin · Özdegerlerinin Yaklaşık Hesabı

Bu çalışmada, belirli rasyonel çekirdekli integral operatörlerin özdeğerlerinin yaklaşık hesaplarını Ritz yaklaşım yöntemi kullanarak hesaplayacağız

Trace ve Kellogg Yöntemleri Kullanılarak İntegral Operatörlerinin Özdeğerlerinin Nümerik Hesabı

Bu çalışmada, Trace ve Kellogg yaklaşım yöntemleri kullanılarak belirli rasyonel çekirdekli integral operatörlerinin özdeğerleri hesaplanmıştır