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1.  Analyses of expressed sequence tags in Neurospora reveal rapid evolution of genes associated with the early stages of sexual reproduction in fungi 
The broadly accepted pattern of rapid evolution of reproductive genes is primarily based on studies of animal systems, although several examples of rapidly evolving genes involved in reproduction are found in diverse additional taxa. In fungi, genes involved in mate recognition have been found to evolve rapidly. However, the examples are too few to draw conclusions on a genome scale.
In this study, we performed microarray hybridizations between RNA from sexual and vegetative tissues of two strains of the heterothallic (self-sterile) filamentous ascomycete Neurospora intermedia, to identify a set of sex-associated genes in this species. We aligned Expressed Sequence Tags (ESTs) from sexual and vegetative tissue of N. intermedia to orthologs from three closely related species: N. crassa, N. discreta and N. tetrasperma. The resulting four-species alignments provided a dataset for molecular evolutionary analyses. Our results confirm a general pattern of rapid evolution of fungal sex-associated genes, compared to control genes with constitutive expression or a high relative expression during vegetative growth. Among the rapidly evolving sex-associated genes, we identified candidates that could be of importance for mating or fruiting-body development. Analyses of five of these candidate genes from additional species of heterothallic Neurospora revealed that three of them evolve under positive selection.
Taken together, our study represents a novel finding of a genome-wide pattern of rapid evolution of sex-associated genes in the fungal kingdom, and provides a list of candidate genes important for reproductive isolation in Neurospora.
PMCID: PMC3571971  PMID: 23186325
Neurospora; Reproductive genes; dN/dS; Speciation; Microarray
2.  From where did the Western honeybee (Apis mellifera) originate? 
Ecology and Evolution  2012;2(8):1949-1957.
The native range of the honeybee Apis mellifera encompasses Europe, Africa, and the Middle East, whereas the nine other species of Apis are found exclusively in Asia. It is therefore commonly assumed that A. mellifera arose in Asia and expanded into Europe and Africa. However, other hypotheses for the origin of A. mellifera have also been proposed based on phylogenetic trees constructed from genetic markers. In particular, an analysis based on >1000 single-nucleotide polymorphism markers placed the root of the tree of A. mellifera subspecies among samples from Africa, suggestive of an out-of-Africa expansion. Here, we re-evaluate the evidence for this and other hypotheses by testing the robustness of the tree topology to different tree-building methods and by removing specimens with a potentially hybrid background. These analyses do not unequivocally place the root of the tree of A. mellifera subspecies within Africa, and are potentially consistent with a variety of hypotheses for honeybee evolution, including an expansion out of Asia. Our analyses also support high divergence between western and eastern European populations of A. mellifera, suggesting they are likely derived from two distinct colonization routes, although the sources of these expansions are still unclear.
PMCID: PMC3433997  PMID: 22957195
Bioinformatics; genomics; population genetics
3.  A computerized Infusion Pump for control of tissue tracer concentration during Positron Emission Tomography in vivo Pharmacokinetic/Pharmacodynamic measurements 
A computer controlled infusion pump (UIPump) for regulation of target tissue concentration of radioactive compounds was developed for use in biological research and tracer development for PET.
Based on observed tissue or plasma kinetics after a bolus injection of the tracer an algorithm calculates the infusion needed to obtain a specified target kinetic curve. A computer feeds this infusion scheme into an infusion pump connected to an animal via a venous catheter. The concept was validated using [11C]Flumazenil administrated to Sprague-Dawley rats where the whole brain distribution and kinetic of the tracer was measured over time using a microPET-scanner. The accuracy and precision of the system was assessed by producing steady-state levels of the tracer and by mimicking kinetics after oral administration.
Various kinetic profiles could be generated, including rapid achievement of constant levels, or step-wise increased levels. The resulting tissue curves had low deviation from the target curves according to the specified criteria: AUC (%): 4.2 ± 2.8, Maximal deviation (%): 13.6 ± 5.0 and R2: 0.95 ± 0.02.
The UIPump-system is suitable for use in PET-research for assessment of PK/PD properties by simulation of different tracer tissue kinetics in vivo.
PMCID: PMC2430701  PMID: 18513382

Results 1-3 (3)