The influence of sex on gene expression and protein evolution in Drosophila melanogaster

A long-standing question in evolutionary biology concerns the molecular causes underlying adaptive evolution. These can either stem from structural changes in proteins or from changes in the expression patterns of proteins or mature RNAs. Over the last decade, many studies have shown that gene expression changes can have a huge impact on the phenotype of an organism and play an important role in adaptive evolution. A major prerequisite for adaptive evolution to occur at the gene expression level is the presence of expression variation among members of a population. This variation serves as the raw material for adaptive evolution. The genetic causes underlying changes in expression patterns can either be located in cis-regulatory regions of the affected gene, such as transcription factor binding sites, or in trans-regulatory regions, such as transcription factors. Mutations in cis-regulatory elements have relatively few pleiotropic effects and their effects are often additive, thus, cis-regulatory changes are thought to be especially well-suited targets of selection. A major factor influencing gene expression is the sex of an organism. The sex-bias of a gene also influences the pace at which proteins evolve, such that male-biased genes often show more rapid evolution than female-biased or unbiased genes between Drosophila species. Here, we investigated genome-wide gene expression variation in adult females of two populations of D. melanogaster, one from the ancestral species range (Zimbabwe) and one from the derived species range (the Netherlands). We found relatively little expression polymorphism present within the populations and high expression divergence between the populations. More than 500 genes were expressed differentially between the populations. These are candidate genes for those that have undergone adaptive regulatory evolution to the new, derived environment. When comparing our study of female adults to a study investigating male adult flies of the same populations, we found that there is significantly less expression polymorphism in females within the populations but significantly more expression divergence between the populations. Further, there was little overlap in genes that differ in expression between the populations in males and females. This suggests that general differences exist between the sexes in gene expression regulation and that regulatory evolution has been mainly sex-specific. Our findings show that extensive gene expression variation exists in D. melanogaster and further highlight the importance of accounting for sex when investigating gene expression. In order to elucidate the genetic and evolutionary mechanisms that underlie differential gene expression between the populations, we employed a candidate gene approach. Analysis of molecular variation in the coding and upstream regions of several differentially expressed genes in both populations revealed evidence for a recent selective sweep in the European population for the gene CG34330. In the putative promoter region of the gene, there is one indel and one SNP where a derived variant is fixed in the European population, but at low frequency in the African population. These are candidates for those variants that control the expression level of the gene. For another gene, Jon99Ciii, we found evidence for recurrent structural protein evolution acting since the split of D. melanogaster from D. simulans and D. sechellia. However, no evidence for recent regulatory evolution could be found for this gene. Motivated by findings that male-biased genes often evolve faster than both female- and unbiased genes between Drosophila species, we examined the molecular evolution of sex-biased genes and their contribution to within-population polymorphism, between-population divergence and between-species divergence in D. melanogaster and D. ananassae. This was studied on both the DNA-sequence level and the expression level. We found strong purifying selection limiting protein sequence variation within species. In contrast, a high proportion of divergence could be attributed to positive selection. In D. melanogaster, male-biased genes showed the highest fraction of adaptive substitutions, a pattern that was especially pronounced on the X chromosome. In contrast, male-biased genes did not show higher variation within or between populations, suggesting that inter-species divergence is not just a simple extension of inter-population divergence and intra-population variation. For D. ananassae, we did not observe a higher rate of adaptive evolution for male-biased genes, a finding that suggests that the type or strength of selection acting on sex-biased genes differs between lineages. Similarly, on the expression level, we found that sex-biased genes show high expression divergence between species, but low divergence between populations

Wettbewerb und Regulierung in der globalen Internetökonomie: Eine rechtsvergleichende Studie zwischen europäischem und US-amerikanischem Recht

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A rulebook for peptide control of legume–microbe endosymbioses

Plants engage in mutually beneficial relationships with microbes, such as arbuscular mycorrhizal fungi or nitrogen-fixing rhizobia, for optimized nutrient acquisition. In return, the microbial symbionts receive photosynthetic carbon from the plant. Both symbioses are regulated by the plant nutrient status, indicating the existence of signaling pathways that allow the host to fine-tune its interactions with the beneficial microbes depending on its nutrient requirements. Peptide hormones coordinate a plethora of developmental and physiological processes and, recently, various peptide families have gained special attention as systemic and local regulators of plant–microbe interactions and nutrient homeostasis. In this review, we identify five \u27rules\u27 or guiding principles that govern peptide function during symbiotic plant–microbe interactions, and highlight possible points of integration with nutrient acquisition pathways

How to enforce due diligence? Making EU-legislation on 'conflict minerals' effective

To reach the objectives stated in the draft legislation, the European Union has to make due diligence on “conflict minerals” mandatory for EU companies. This will increase the demand for “conflict-free” minerals, which will act as an incentive for speeding up local mapping and tracing efforts and the return of smelters to the DR Congo. Downstream companies are in a position to conduct due diligence with marginal to manageable costs, despite the complexity involved. The competitive disadvantage of European companies towards Asian companies is more imaginary than real. For due diligence legislation to be effective in conflict regions, EU actors ought to support multi-stakeholder initiatives on the ground that have greater credibility than government or industry schemes. Instead of rigid certification procedures that create high administrative burdens on state and economic actors, priority should be given to flexible and reliable instruments of mapping and tracing that smelters can use for their supply chain due diligence. In conflict regions, certificates risk being tainted by reports of fraud, as the challenges to governance can be expected to be similar to those in the Great Lakes region. A policy approach that enables rather than prohibits artisanal mining is better suited to providing market access to informal artisanal mining that does not have links to armed actors. Legality should not be made a precondition for recognising artisanal mines as conflict-free to avoid punishment of an entire sector for the links to conflict financing of a few

Gas inflows towards the nucleus of NGC1358

We use optical spectra from the inner 1.8 $\times$ 2.5kpc$^2$ of the Seyfert 2 galaxy NGC1358, obtained with the GMOS integral field spectrograph on the Gemini South telescope at a spatial resolution of $\approx$ 165pc, to assess the feeding and feedback processes in this nearby active galaxy. Five gaseous kinematical components are observed in the emission line profiles. One of the components is present in the entire field-of-view and we interpret it as due to gas rotating in the disk of the galaxy. Three of the remaining components we interpret as associated to active galactic nucleus (AGN) feedback: a compact unresolved outflow in the inner 1 arcsec and two gas clouds observed at opposite sides of the nucleus, which we propose have been ejected in a previous AGN burst. The disk component velocity field is strongly disturbed by a large scale bar. The subtraction of a velocity model combining both rotation and bar flows reveals three kinematic nuclear spiral arms: two in inflow and one in outflow. We estimate the mass inflow rate in the inner 180pc obtaining $\dot{M}_{in}$ $\approx$ 1.5 $\times 10^{-2}$M$_{\odot}$yr$^{-1}$, about 160 times larger than the accretion rate necessary to power this AGN.Comment: 12 pages, 11 figures, accepted for publication in Monthly Notices of the Royal Astronomical Society. arXiv admin note: text overlap with arXiv:1701.0086

How Do Firms Form Expectations of Aggregate Growth? New Evidence from a Large-scale Business Survey

Expectations are highly relevant for macroeconomic dynamics. Yet, the empirical evidence about properties of corporate macroeconomic expectations is scarce. Using new survey data on quantitative growth expectations of firms in Germany, we show that expectations are highly dispersed. The degree of dispersion depends on firm size and on how important the general economy is for the business of firms, supporting theories of rational inattention. Firms seem to extrapolate from local economic conditions and business experiences to aggregate growth expectations. Differences in growth expectations are associated with di erences in firms' Investment and labor demand.Not Reviewe

Organofunktionalisierung anorganischer Oberflächen vor dem Hintergrund industrieller Anwendungen

[no abstract

Routinetaugliche mikromorphometrische Klassifikationssysteme für Sentinel-Lymphknoten-Metastasen

Das maligne Melanom, sowie Tumore der Haut allgemein, zeigen die stärkste Inzidenzzunahme unter allen soliden Tumoren in den letzten Jahrzehnten. Dies ist ein Hauptgrund für die stetige Weiterentwicklung schon bestehender Diagnoseverfahren. Für die Bewertung der Tumorlast im SLN haben sich im Laufe der letzten Jahre hauptsächlich zwei Ansätze etabliert: Zum einen die Mitte der 1990er in Augsburg entstandene S-Klassifikation, basierend auf der Tumoreindringtiefe im SLN und zum anderen die 2006 aus Rotterdam stammende R-Klassifikation mit dem maximalen Metastasendurchmesser als Ausgangsmaß. Ziel dieser Arbeit war es, diese beiden Klassifikationssysteme in ihrer prognostischen Wertigkeit zu vergleichen, Kombinationen beider Systeme herauszuarbeiten und einen Ausblick auf eine differenziertere Indikation zur CLND zu geben. Für die statistische Analyse wurden 280 in der dermatologischen Klinik Augsburg behandelte Patienten im Hinblick auf das ER, die FM, das MMÜ und das GÜ analysiert. Dies erfolgte mittels der Kaplan-Meier-Analyse univariat und mit Hilfe der Cox-Regression multivariat. Sowohl die S- als auch die R-Klassifikation lieferten in beiden Verfahren durchwegs signifikante Ergebnisse und können als erstrangige Prognosefaktoren gewertet werden. Dies gilt ebenso für zwei hier untersuchte Kombinations-Klassifikationen (AR- und RS-Klassifikation), die jeweils beide oben genannte Messkriterien einbeziehen. Im Vergleich zur S-Klassifikation konnten in vorliegender Analyse die R-, die AR- und die RS-Klassifikation etwas besser abschneiden. Für die Frage nachgeschalteter LK-Metastasen ergab sich für AR1-Patienten das geringste Risiko (8%), weshalb diesen Patienten unter Maßgabe engmaschiger Sonographiekontrollen die CLND erspart bleiben kann. Zusätzliche Bedeutung gewinnt die differenzierte Tumorlastbestimmung im SLN neuerdings auch für die adjuvante medikamentöse Therapie von Melanompatienten nach Abschluss der chirurgischen Maßnahmen

No rebel without a cause: shifting the debate about conflict minerals in eastern DRC

Precluding conflict financing through the minerals sector has come to be seen as the panacea to ending conflicts in the eastern Democratic Republic of the congo (DRc). The US Dodd-Frank-Act (2010) and European draft legislation attempt to reduce the financing of armed groups in conflict zones by asking companies to conduct due diligence along their supply chains to avoid the purchase of "conflict minerals". This Working Paper lays open the misconceptions that have led to such a narrow regulatory approach towards the congolese conundrum and analyses the consequences of implementing this legislation without embedding it in a wider agenda for peace. The authors argue that regulation on conflict minerals can only contribute to solving conflicts in eastern DRc if it becomes part of a wider approach to peacebuilding, which takes into account the complex reality of eastern DRc's conflicts