Design and construction of a new Drosophila species, D.synthetica, by synthetic regulatory evolution

Here, I merge the principles of synthetic biology1,2 and regulatory evolution3-11 to create a new species12-15 with a minimal set of known elements. Using preexisting transgenes and recessive mutations of Drosophila melanogaster, a transgenic population arises with small eyes and a different venation pattern that fulfills the criteria of a new species according to Mayr's "Biological Species Concept"7,10. The genetic circuit entails the loss of a non-essential transcription factor and the introduction of cryptic enhancers. Subsequent activation of those enhancers causes hybrid lethality. The transition from "transgenic organisms" towards "synthetic species", such as Drosophila synthetica, constitutes a safety mechanism to avoid hybridization with wild type populations and preserve natural biodiversity16-18. Drosophila synthetica is the first transgenic organism that cannot hybridize with the original wild type population but remains fertile when crossed with other transgenic animals.

Molecular mechanisms involved in T cell migration across the blood-brain barrier

In the healthy individuum lymphocyte traffic into the central nervous system (CNS) is very low and tightly controlled by the highly specialized blood-brain barrier (BBB). In contrast, under inflammatory conditions of the CNS such as in multiple sclerosis or in its animal model experimental autoimmune encephalomyelitis (EAE) circulating lymphocytes and monocytes/macrophages readily cross the BBB and gain access to the CNS leading to edema, inflammation and demyelination. Interaction of circulating leukocytes with the endothelium of the blood-spinal cord and blood-brain barrier therefore is a critical step in the pathogenesis of inflammatory diseases of the CNS. Leukocyte/endothelial interactions are mediated by adhesion molecules and chemokines and their respective chemokine receptors. We have developed a novel spinal cord window preparation, which enables us to directly visualize CNS white matter microcirculation by intravital fluorescence videomicroscopy. Applying this technique of intravital fluorescence videomicroscopy we could provide direct in vivo evidence that encephalitogenic T cell blasts interact with the spinal cord white matter microvasculature without rolling and that alpha4-integrin mediates the G-protein independent capture and subsequently the G-protein dependent adhesion strengthening of T cell blasts to microvascular VCAM-1. LFA-1 was found to neither mediate the G-protein independent capture nor the G- protein dependent initial adhesion strengthening of encephalitogenic T cell blasts within spinal cord microvessel, but was rather involved in T cell extravasation across the vascular wall into the spinal cord parenchyme. Our observation that G-protein mediated signalling is required to promote adhesion strengthening of encephalitogenic T cells on BBB endothelium in vivo suggested the involvement of chemokines in this process. We found functional expression of the lymphoid chemokines CCL19/ELC and CCL21/SLC in CNS venules surrounded by inflammatory cells in brain and spinal cord sections of mice afflicted with EAE suggesting that the lymphoid chemokines CCL19 and CCL21 besides regulating lymphocyte homing to secondary lymphoid tissue might be involved in T lymphocyte migration into the immuneprivileged CNS during immunosurveillance and chronic inflammation. Here, I summarize our current knowledge on the sequence of traffic signals involved in T lymphocyte recruitment across the healthy and inflamed blood-brain and blood-spinal cord barrier based on our in vitro and in vivo investigations.

The horse genome project - sequence based insights into male reproductive mechanisms

The growing knowledge on physiology, cell biology and biochemistry of the reproductive organs has provided many insights into molecular mechanisms that are required for successful reproduction. Research directed at the investigation of reproduction physiology in domestic animals was hampered in the past by a lack of species-specific genomic information. The genome sequences of dog, cattle and horse have become publicly available in 2005, 2006 and 2007 respectively. Although the gene content of mammalian genomes is generally very similar, genes involved in reproduction tend to be less conserved than the average mammalian gene. The availability of genome sequences provides a valuable resource to check whether any protein that may be known from human or mouse research is present in cattle and/or horse as well. Currently there are more than 200 genes known that are involved in the production of fertile sperm cells. Great progress has been made in the understanding of genetic aberrations that lead to male infertility. Additionally, the first genetic mechanisms are being discovered that contribute to the quantitative variation of fertility traits in fertile male animals. Here, I will review some selected aspects of genetic research in male fertility and offer some perspectives for the use of genomic sequence information.

Impact factor statistics and publication practice: What can we learn? (Editorial)

Peer review procedures and citation statistics are important yet often neglected components of the scientific publication process. Here I discuss fundamental consequences of such quality measures for the scientific community and propose three remedial actions: (1) use of a ''Combined Impact Estimate'' as a measure of citation statistics, (2) adoption of an open reviewing policy and (3) acceleration of the publication process in order to raise the reputation of the entire discipline (in our case: behavioural science). Authors, reviewers and editors are invited to contribute to the improvement of publication practice.

Resolving the tragedy of the commons: the feedback between intraspecific conflict and population density

Competition and conflict among individuals can favour exploitative strategies that undermine the common good. Theory suggests that this can lead to a tragedy of the commons and ultimately population extinction, a phenomenon known as evolutionary suicide. Here, I present a model of the evolutionary tragedy of the commons that explicitly considers the population dynamics where individuals invest in individually costly competitive traits. In the simplest form, this supports the notion that selection for high levels of conflict can cause evolutionary suicide. However, as competition comes with survival and fecundity costs, a feedback between the investment in competition and population density can act to reduce the level of conflict and prevent the population from going extinct. This suggests that the interaction between population ecology and the evolution of competition and conflict among individuals may be an important mechanism in resolving the level of competition and conflict among individuals.

The “Out of Africa Tribe” (II): Paleolithic warriors with big canoes and protective weapons

It is generally difficult to establish a timeline for the appearance of different technologies and tools during human cultural evolution. Here I use stochastic character mapping of discrete traits using human mtDNA phylogenies rooted to the Reconstructed Sapiens Reference Sequence (RSRS) as a model to address this question. The analysis reveals that the ancestral state of Homo sapiens was hunting, using material innovations that included bows and arrows, stone axes and spears. However, around 80,000 y before present, a transition occurred, from this ancestral hunting tradition, toward the invention of protective weapons such as shields, the appearance of ritual fighting as a socially accepted behavior and the construction of war canoes for the fast transport of large numbers of warriors. This model suggests a major cultural change, during the Palaeolithic, from hunters to warriors. Moreover, in the light of the recent Out of Africa Theory, it suggests that the “Out of Africa Tribe” was a tribe of warriors that had developed protective weapons such as shields and used big war canoes to travel the sea coast and big rivers in raiding expeditions.

Semantic Representation of Synaesthesia

Synaesthesia has multifaceted consequences for both subjective experience and cognitive performance. Here, I broach the issue of how synaesthesia is represented in semantic memory. I hypothesize that, for example, in grapheme colour synaesthesia, colour is represented as an additional feature in the semantic network that enables the formation of associations that are not present in non-synaesthetes. Thus, synaesthesia provokes richer memory representations which enable learning opportunities that are not present in non-synaesthetes, provides additional memory cues, and may trigger creative ideas.

Implicit task sequence learning

Implicit task sequence learning (TSL) can be considered as an extension of implicit sequence learning which is typically tested with the classical serial reaction time task (SRTT). By design, in the SRTT there is a correlation between the sequence of stimuli to which participants must attend and the sequence of motor movements/key presses with which participants must respond. The TSL paradigm allows to disentangle this correlation and to separately manipulate the presences/absence of a sequence of tasks, a sequence of responses, and even other streams of information such as stimulus locations or stimulus-response mappings. Here I review the state of TSL research which seems to point at the critical role of the presence of correlated streams of information in implicit sequence learning. On a more general level, I propose that beyond correlated streams of information, a simple statistical learning mechanism may also be involved in implicit sequence learning, and that the relative contribution of these two explanations differ according to task requirements. With this differentiation, conflicting results can be integrated into a coherent framework.

The closing door of climate targets

Robust evidence from a range of climate–carbon cycle models shows that the maximum warming relative to pre-industrial times caused by the emissions of carbon dioxide is nearly proportional to the total amount of emitted anthropogenic carbon (1, 2). This proportionality is a reasonable approximation for simulations covering many emissions scenarios for the time frame 1750 to 2500 (1). This linear relationship is remarkable given the different complexities of the models and the wide range of emissions scenarios considered. It has direct implications for the possibility of achieving internationally agreed climate targets such as those mentioned in the Copenhagen Accord and the Cancun Agreements (3, 4). Here I explain some of the implications of the linear relationship between peak warming and total cumulative carbon emissions.

The English of The Sleeping Lady: An exploration of the historical and current influences on the English of Kosrae

Kosrae, or ‘The Island of The Sleeping Lady’ as it is known to locals, is the most remote island of the Federated States of Micronesia (FSM), located in the western Pacific. FSM is an independent sovereign nation consisting of four state in total: Pohnpei, Chuuk, Yap and Kosrae. First claimed by the Spanish, who were forced to cede FSM to Germany in 1899. In 1914, the Japanese took military possession of the region resulting in considerable economic, social and political change for the islands’ inhabitants. By 1947 after WWII, the islands formed part of the Trust Territory of the Pacific Islands commissioned by the UN and administered by the US. The FSM became an independent nation in 1986 while still retaining affiliation with the US under a ‘Compact of Free Association’ encouraging the officiating of English as a language of FSM, alongside local languages. Here I examine the presence and uses of English in Kosrae with reference to these socio-historical influences. First, I discuss the extralinguistic factors which have shaped the English that is currently found on Kosrae. Secondly, I assess the use of English in this community in light of Schneider’s (2007) ‘Dynamic Model’. Finally, an overview of the salient linguistic characteristics of Kosraean English, based on data collected in informal conversations on the island, will be presented. The overall objective is to present a socio-historical, political and linguistic description of a hitherto unexamined English emerging in a postcolonial environment. Schneider, E. (2007). Postcolonial Englishes. Cambridge: Cambridge University Press. Research Interests: Global Englishes

Cryptic invasion drives phenotypic changes in central European threespine stickleback

Cryptic invasions are commonly associated with genetic changes of the native species or genetic lineage that the invaders replace. Phenotypic shifts resulting from cryptic invasions are less commonly reported given the relative paucity of historical specimens that document such phenotypic changes. Here, I study such a case in two populations of threespine stickleback from central Europe, comparing contemporary patterns of gene flow with phenotypic changes between historical and contemporary population samples. I find gene flow from an invasive lineage to be associated with significant phenotypic changes, where the degree of phenotypic change corresponds with the level of gene flow that a population receives. These findings underline the utility of combining genetic approaches with phenotypic data to estimate the impact of gene flow in systems where anthropogenic alterations have removed former geographic barriers promoting cryptic invasions.

Am I (un)safe here? Chemotherapy patients' perspectives towards engaging in their safety

To assess chemotherapy patients' perceptions of safety and their attitudes towards participating in error-prevention strategies.