Evidence for convergent nucleotide evolution and high allelic turnover rates at the complementary sex determiner (csd) gene of western and Asian honey bees

Our understanding of the impact of recombination, mutation, genetic drift and selection on the evolution of a single gene is still limited. Here we investigate the impact of all of these evolutionary forces at the complementary sex determiner (csd) gene which evolves under a balancing mode of selection. Females are heterozygous at the csd gene and males are hemizygous; diploid males are lethal and occur when csd is homozygous. Rare alleles thus have a selective advantage, are seldom lost by the effect of genetic drift and are maintained over extended periods of time when compared to neutral polymorphisms. Here, we report on the analysis of 17, 19 and 15 csd alleles of Apis cerana, Apis dorsata and Apis mellifera honey bees respectively. We observed great heterogeneity of synonymous (pi S) and nonsynonymous (pi N) polymorphisms across the gene, with a consistent peak in exon 6 and 7. We propose that exons 6 and 7 encode the potential specifying domain (csd-PSD) which has accumulated elevated nucleotide polymorphisms over time by balancing selection. We observed no direct evidence that balancing selection favors the accumulation of nonsynonymous changes at csd-PSD (pi N/pi S ratios are all < 1, ranging from 0.6 to 0.95). We observed an excess of shared nonsynonymous changes, which suggests that strong evolutionary constraints are operating at csd-PSD resulting in the independent accumulation of the same nonsynonymous changes in different alleles across species (convergent evolution). Analysis of a csd-PSD genealogy revealed relatively short average coalescence times (~6 million years), low average synonymous nucleotide diversity (pi S < 0.09) and a lack of trans-specific alleles which substantially contrasts with previously analyzed loci under strong balancing selection. We excluded the possibility of a burst of diversification after population bottlenecking and intragenic recombination as explanatory factors, leaving high turn-over rates as the explanation for this observation. By comparing observed allele richness and average coalescence times with a simplified model of csd-coalescence, we found that small long term population sizes (i.e. Ne <104), but not high mutation rates, can explain short maintenance times, implicating a strong impact of genetic drift on the molecular evolution of highly social honey bees

UE112_PGM-1: An open-port low-energy beamline at the BESSY II undulator UE112

The X-ray optical and mechanical designs of a low-energy high-flux VUV- to soft-X-ray beamline for photon energies between 17 and 200 eV (with lower flux up to 690 eV) are presented

Repeated evolution of a derived feature: insights from complementary sex determination

Trabalho de projeto do mestrado em Economia (Economia Financeira), apresentado à Faculdade de Economia da Universidade de Coimbra, sob a orientação de António Portugal e Rita MartinsO trabalho de projeto que se segue tem como objetivo principal refletir sobre os impactos económicos de um grande evento desportivo no país onde é organizado e realizado. Em primeiro lugar, são identificados os conceitos chave que permitem desenvolver uma correta interpretação do estudo. Da revisão da literatura teórica, apresentam-se autores que expõem os diversos impactos, não só económicos, mas também socioculturais, ambientais e na imagem exterior do país em questão. A análise prossegue com o estudo das variações do produto num conjunto de períodos em que se considera a presença do evento desportivo, comparativamente a períodos anteriores e posteriores, nos países que realizaram um grande evento desportivo como o Campeonato do Mundo de futebol, o Campeonato da Europa de futebol e os Jogos Olímpicos. Essa análise aponta para uma tendência de aceleração do crescimento económico quando ocorre um dos acontecimentos em estudo. Com recurso a estudos econométricos, calculam-se coeficientes que permitem estimar o efeito positivo destes eventos sobre o crescimento económico. De seguida, focando o Euro 2004 organizado e realizado em Portugal, verificam-se que infraestruturas foram construídas e de que forma foram financiadas, assim como os impactos decorrentes das mesmas, nomeadamente, o acréscimo na produção, o acréscimo de postos de trabalho e o acréscimo de rendimentos salariais. Ao nível da estatística descritiva são examinadas três variáveis, o número de hóspedes estrangeiros, a riqueza produzida e o emprego, nas regiões em que se construíram/remodelaram os estádios utilizados no Euro 2004, e comparadas estas variações, em cada região e no conjunto das regiões, com as variações no espaço nacional. Esta análise permite verificar taxas de crescimento, do conjunto das regiões, superiores às taxas de crescimento nacionais, nos períodos seguintes ao evento e, portanto, o efeito positivo do referido evento no turismo, assim como o impacto na taxa de crescimento da riqueza produzida, principalmente, no ano em que ocorreu o evento, e ainda, os efeitos sobre a distribuição da mão-de-obra no país, que mostram indícios de deslocação de mão-de-obra entre regiões. Em conclusão, a organização e realização de um grande evento desportivo pode ser um acontecimento que afeta positivamente o crescimento económico de um país, por via dos efeitos criadas pelas infraestruturas e por via da remodelação da imagem do país no exterior

On the relevance of technical variation due to building pools in microarray experiments

Background Pooled samples are frequently used in experiments measuring gene expression. In this method, RNA from different individuals sharing the same experimental conditions and explanatory variables is blended and their concentrations are jointly measured. As a matter of principle, individuals are represented in equal shares in each pool. However, some degree of disproportionality may arise from the limits of technical precision. As a consequence a special kind of technical error occurs, which can be modelled by a respective variance component. Previously published theory - allowing for variable pool sizes - has been applied to four microarray gene expression data sets from different species in order to assess the practical relevance of this type of technical error in terms of significance and size of this variance component. Results The number of transcripts with a significant variance component due to imperfect blending was found to be 4329 (23 %) in mouse data and 7093 (49 %) in honey bees, but only 6 in rats and none whatsoever in human data. These results correspond to a false discovery rate of 5 % in each data set. The number of transcripts found to be differentially expressed between treatments was always higher when the blending error variance was neglected. Simulations clearly indicated overly-optimistic (anti-conservative) test results in terms of false discovery rates whenever this source of variability was not represented in the model. Conclusions Imperfect equality of shares when blending RNA from different individuals into joint pools of variable size is a source of technical variation with relevance for experimental design, practice at the laboratory bench and data analysis. Its potentially adverse effects, incorrect identification of differentially expressed transcripts and overly-optimistic significance tests, can be fully avoided, however, by the sound application of recently established theory and models for data analysis

Sex Determination in Honeybees: Two Separate Mechanisms Induce and Maintain the Female Pathway

Sex determination in honeybees is realized by the csd and the fem gene that establish and maintain, throughout development, sexual fates via the control of alternative splicing

Witches, pagans and historians:an extended review of Max Dashu, <i>Witches and Pagans: Women in European Folk Religion, 700-1000 </i>

Additional file 4: Table S4. DEGs associated with the HB sources but not with the behavior. A modified t-test was performed on the log-transformed transcription ratios gained from 82 hybridizations. Oligo Ids, Gene Ids, and Comments are quoted from the UIUC Honey bee oligo 13 K v1 annotation file (May 2007)