Descritpion of a double mutant strain of Drosophila melanogaster useful for genetic laboratory courses.

Many years ago, individuals showing drastically reduced eyes arose in our laboratory e (ebony) strain (Bridges and Morgan, 1923). We selected those flies presenting both traits and constituted a new double mutant strain e su (e, ebony; su, 'sense ulls', eyes drastically reduced). Both mutations were linked and located in the chromosome III. We used this strain in linkage analyses with our undergraduate students. [...

Argonaute2 Suppresses Drosophila Fragile X Expression Preventing Neurogenesis and Oogenesis Defects

Fragile X Syndrome is caused by the silencing of the Fragile X Mental Retardation gene (FMR1). Regulating dosage of FMR1 levels is critical for proper development and function of the nervous system and germ line, but the pathways responsible for maintaining normal expression levels are less clearly defined. Loss of Drosophila Fragile X protein (dFMR1) causes several behavioral and developmental defects in the fly, many of which are analogous to those seen in Fragile X patients. Over-expression of dFMR1 also causes specific neuronal and behavioral abnormalities. We have found that Argonaute2 (Ago2), the core component of the small interfering RNA (siRNA) pathway, regulates dfmr1 expression. Previously, the relationship between dFMR1 and Ago2 was defined by their physical interaction and co-regulation of downstream targets. We have found that Ago2 and dFMR1 are also connected through a regulatory relationship. Ago2 mediated repression of dFMR1 prevents axon growth and branching defects of the Drosophila neuromuscular junction (NMJ). Consequently, the neurogenesis defects in larvae mutant for both dfmr1 and Ago2 mirror those in dfmr1 null mutants. The Ago2 null phenotype at the NMJ is rescued in animals carrying an Ago2 genomic rescue construct. However, animals carrying a mutant Ago2 allele that produces Ago2 with significantly reduced endoribonuclease catalytic activity are normal with respect to the NMJ phenotypes examined. dFMR1 regulation by Ago2 is also observed in the germ line causing a multiple oocyte in a single egg chamber mutant phenotype. We have identified Ago2 as a regulator of dfmr1 expression and have clarified an important developmental role for Ago2 in the nervous system and germ line that requires dfmr1 function

Buffering and the evolution of chromosome-wide gene regulation

Copy number variation (CNV) in terms of aneuploidies of both entire chromosomes and chromosomal segments is an important evolutionary driving force, but it is inevitably accompanied by potentially problematic variations in gene doses and genomic instability. Thus, a delicate balance must be maintained between mechanisms that compensate for variations in gene doses (and thus allow such genomic variability) and selection against destabilizing CNVs. In Drosophila, three known compensatory mechanisms have evolved: a general segmental aneuploidy-buffering system and two chromosome-specific systems. The two chromosome-specific systems are the male-specific lethal complex, which is important for dosage compensation of the male X chromosome, and Painting of fourth, which stimulates expression of the fourth chromosome. In this review, we discuss the origin and function of buffering and compensation using Drosophila as a model

Sequencing of Pooled DNA Samples (Pool-Seq) Uncovers Complex Dynamics of Transposable Element Insertions in Drosophila melanogaster

Transposable elements (TEs) are mobile genetic elements that parasitize genomes by semi-autonomously increasing their own copy number within the host genome. While TEs are important for genome evolution, appropriate methods for performing unbiased genome-wide surveys of TE variation in natural populations have been lacking. Here, we describe a novel and cost-effective approach for estimating population frequencies of TE insertions using paired-end Illumina reads from a pooled population sample. Importantly, the method treats insertions present in and absent from the reference genome identically, allowing unbiased TE population frequency estimates. We apply this method to data from a natural Drosophila melanogaster population from Portugal. Consistent with previous reports, we show that low recombining genomic regions harbor more TE insertions and maintain insertions at higher frequencies than do high recombining regions. We conservatively estimate that there are almost twice as many “novel” TE insertion sites as sites known from the reference sequence in our population sample (6,824 novel versus 3,639 reference sites, with on average a 31-fold coverage per insertion site). Different families of transposable elements show large differences in their insertion densities and population frequencies. Our analyses suggest that the history of TE activity significantly contributes to this pattern, with recently active families segregating at lower frequencies than those active in the more distant past. Finally, using our high-resolution TE abundance measurements, we identified 13 candidate positively selected TE insertions based on their high population frequencies and on low Tajima's D values in their neighborhoods

Encuesta nacional sobre manejo preoperatorio y criterios de selección de pacientes en las unidades de cirugía mayor ambulatoria españolas National survey of preoperative management and patient selection in ambulatory surgery centers

Introducción: El objetivo de este estudio es conocer los criterios de selección y preparación de los pacientes en las diferentes unidades de cirugía mayor ambulatoria (UCMA) españolas y su impacto en los resultados de éstas; también se comparan dichos resultados según el tipo de estructura funcional de las unidades (autónoma o integrada). Material y método: Estudio descriptivo transversal mediante encuesta postal. Encuesta con los siguientes apartados: tipo de unidad, cartera de servicios, criterios de selección, evaluación, manejo preoperatorio e indicadores cualitativos y cuantitativos de la actividad realizada en el año 2000. Se incluyeron 123 unidades, con un nivel de respuesta del 39%. Resultados: Existe un alto grado de consenso en los criterios de selección. En el 97,9% de las unidades se utiliza la consulta de anestesia para la evaluación preoperatoria. La solicitud sistemática de las pruebas de laboratorio es elevada (89% para la hemostasia y el hemograma, 72,9% para la bioquímica), mientras que para la radiografía de tórax (33,3%) y el ECG (35,4%) se utilizan criterios más selectivos. La implantación de protocolos para el manejo de afecciones asociadas está poco extendida (25-64,6%). El índice de cancelaciones es ventajoso para las unidades que utilizan la consulta de anestesia en todos los pacientes (el 1,5 frente al 4,4%). Existe una significativa aceptación de pacientes de mayor riesgo quirúrgico-anestésico en las unidades de tipo autónomo respecto a las integradas, así como una significativa disminución del número de ingresos (el 1,2 frente al 1,9%; p = 0,003) de las estancias (240 frente a 367 min; p = 0,002), y del tiempo de recuperación (150 frente a 212 min; p = 0,001). Las diferencias en el resto de los indicadores analizados no revisten significación. Conclusiones: Es necesario profundizar en la consecución de protocolos basados en evidencias científicas para la selección de los pacientes, la evaluación preoperatoria y el manejo perioperatorio de las diferentes enfermedades, así como para la utilización racional de las pruebas de laboratorio. Se constata la necesidad de la consulta anestésica para la evaluación preoperatoria. Los resultados de nuestra encuesta apuntan hacia unos mejores resultados en los indicadores de funcionamiento en las UCMA autónomas frente a las integradas. Existe la posibilidad de definir estándares de calidad y validarlos, para lo cual serán necesarios futuros estudios multicéntricos.Background: The objective of this study was to determine both the selection and preparation criteria in patients in various Spanish ambulatory surgery centers, as well as the impact of these criteria on their results. The results were compared according to the type of functional structure of the units (autonomous or integrated). Material and methods: We performed a cross sectional, descriptive study through postal survey. The survey contained the following items: type of unit, surgical procedures, selection criteria, preoperative assessment and management, and qualitative and quantitative indexes of the activity performed in 2000. A total of 123 units were included with a response rate of 39%. Results: The selection criteria showed a high degree of consensus. The outpatient anesthesia clinic was used for preoperative assessment by 97.9% of the units. Most units routinely requested preoperative tests (hemostasis and hemogram by 89%; biochemical parameters by 72.9%) and to a lesser extent chest X-ray (33.3%) and electrocardiogram (35.4%). The introduction of procedures for the management of coexisting diseases was scarce (25-64.6%). Units using the outpatient anesthesia clinic in all patients had a lower cancellation rate (1.5% vs 4.4%). Autonomous units were significantly more likely to accept patients with high surgical-anesthetic risk than integrated units. Autonomous units also showed a significantly lower number of admissions (1.2% vs 1.9%, p = 0.003), mean stay (240 min vs 367 min, p = 0.002), and recovery time (150 min vs 212 min, p = 0.001) than integrated units. No statistically significant differences were found in the remaining parameters. Conclusions: Scientifically based protocols for patient selection, preoperative assessment and perioperative management of distinct processes and for the rational use of laboratory tests should be more widely used. The need for an outpatient anesthesia clinic for preoperative assessment was notable. The results of our survey indicate that better results in performance indexes are achieved in autonomous ambulatory surgery units than in integrated units. Given the possibility of defining and validating quality standards, further multicenter studies should be performed

Location of the PcG genes on the <i>D</i>. <i>subobscura</i> chromosomes.

<p>The location of the sixteen studied PcG genes is indicated on the polytene chromosomes of <i>D</i>. <i>subobscura</i> (<i>ch cu</i> strain) by arrowheads. All chromosomes have the standard arrangement shown in the cytological map of the species [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0185005#pone.0185005.ref027" target="_blank">27</a>] except the O chromosome that has the O₃₊₄ arrangement that includes the overlapping inversions O₃ and O₄. Chromosomes are identified by capital letters (A, J, U, E and O) at the distal end. The dot-like chromosome is also indicated (Dot).</p

Encuesta nacional sobre manejo preoperatorio y criterios de selección de pacientes en las unidades de cirugía mayor ambulatoria españolas

Introducción: El objetivo de este estudio es conocer los criterios de selección y preparación de los pacientes en las diferentes unidades de cirugía mayor ambulatoria (UCMA) españolas y su impacto en los resultados de éstas; también se comparan dichos resultados según el tipo de estructura funcional de las unidades (autónoma o integrada). Material y método: Estudio descriptivo transversal mediante encuesta postal. Encuesta con los siguientes apartados: tipo de unidad, cartera de servicios, criterios de selección, evaluación, manejo preoperatorio e indicadores cualitativos y cuantitativos de la actividad realizada en el año 2000. Se incluyeron 123 unidades, con un nivel de respuesta del 39%. Resultados: Existe un alto grado de consenso en los criterios de selección. En el 97,9% de las unidades se utiliza la consulta de anestesia para la evaluación preoperatoria. La solicitud sistemática de las pruebas de laboratorio es elevada (89% para la hemostasia y el hemograma, 72,9% para la bioquímica), mientras que para la radiografía de tórax (33,3%) y el ECG (35,4%) se utilizan criterios más selectivos. La implantación de protocolos para el manejo de afecciones asociadas está poco extendida (25-64,6%). El índice de cancelaciones es ventajoso para las unidades que utilizan la consulta de anestesia en todos los pacientes (el 1,5 frente al 4,4%). Existe una significativa aceptación de pacientes de mayor riesgo quirúrgico-anestésico en las unidades de tipo autónomo respecto a las integradas, así como una significativa disminución del número de ingresos (el 1,2 frente al 1,9%; p = 0,003) de las estancias (240 frente a 367 min; p = 0,002), y del tiempo de recuperación (150 frente a 212 min; p = 0,001). Las diferencias en el resto de los indicadores analizados no revisten significación. Conclusiones: Es necesario profundizar en la consecución de protocolos basados en evidencias científicas para la selección de los pacientes, la evaluación preoperatoria y el manejo perioperatorio de las diferentes enfermedades, así como para la utilización racional de las pruebas de laboratorio. Se constata la necesidad de la consulta anestésica para la evaluación preoperatoria. Los resultados de nuestra encuesta apuntan hacia unos mejores resultados en los indicadores de funcionamiento en las UCMA autónomas frente a las integradas. Existe la posibilidad de definir estándares de calidad y validarlos, para lo cual serán necesarios futuros estudios multicéntricos

Summary of synonymous and nonsynonymous polymorphism and divergence with <i>D</i>. <i>guanche</i> in the PcG genes.

<p>Summary of synonymous and nonsynonymous polymorphism and divergence with <i>D</i>. <i>guanche</i> in the PcG genes.</p