248 research outputs found

    Life-History Evolution on Tropidurinae Lizards: Influence of Lineage, Body Size and Climate

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    The study of life history variation is central to the evolutionary theory. In many ectothermic lineages, including lizards, life history traits are plastic and relate to several sources of variation including body size, which is both a factor and a life history trait likely to modulate reproductive parameters. Larger species within a lineage, for example tend to be more fecund and have larger clutch size, but clutch size may also be influenced by climate, independently of body size. Thus, the study of climatic effects on lizard fecundity is mandatory on the current scenario of global climatic change. We asked how body and clutch size have responded to climate through time in a group of tropical lizards, the Tropidurinae, and how these two variables relate to each other. We used both traditional and phylogenetic comparative methods. Body and clutch size are variable within Tropidurinae, and both traits are influenced by phylogenetic position. Across the lineage, species which evolved larger size produce more eggs and neither trait is influenced by temperature components. A climatic component of precipitation, however, relates to larger female body size, and therefore seems to exert an indirect relationship on clutch size. This effect of precipitation on body size is likely a correlate of primary production. A decrease in fecundity is expected for Tropidurinae species on continental landmasses, which are predicted to undergo a decrease in summer rainfall

    eFORGE v2.0: updated analysis of cell type-specific signal in epigenomic data

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    SUMMARY: The Illumina Infinium EPIC BeadChip is a new high-throughput array for DNA methylation analysis, extending the earlier 450k array by over 400,000 new sites. Previously, a method named eFORGE was developed to provide insights into cell type-specific and cell composition effects for 450k data. Here, we present a significantly updated and improved version of eFORGE that can analyse both EPIC and 450k array data. New features include analysis of chromatin states, TF motifs and DNase I footprints, providing tools for EWAS interpretation and epigenome editing. AVAILABILITY: eFORGE v2.0 is implemented as a web tool available from https://eforge.altiusinstitute.org and https://eforge-tf.altiusinstitute.org/. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online

    Perspective from a Younger Generation -- The Astro-Spectroscopy of Gisbert Winnewisser

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    Gisbert Winnewisser's astronomical career was practically coextensive with the whole development of molecular radio astronomy. Here I would like to pick out a few of his many contributions, which I, personally, find particularly interesting and put them in the context of newer results.Comment: 14 pages. (Co)authored by members of the MPIfR (Sub)millimeter Astronomy Group. To appear in the Proceedings of the 4th Cologne-Bonn-Zermatt-Symposium "The Dense Interstellar Medium in Galaxies" eds. S. Pfalzner, C. Kramer, C. Straubmeier, & A. Heithausen (Springer: Berlin

    Diferenças de nichos entre duas espécies simpÑtricas de lagartos (Cnemidophorus abaetensis e C. ocellifer) em habitat de restinga no nordeste do Brasil

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    Differences among sympatric lizard species usually result from differences in the use of three resources: space, time and food or some combination of these three. However, differences in resource utilization among sympatric species may simply reflect their specific ecological needs rather than competitive pressures. In this study, we analyzed the temporal, spatial and food niche of two congeneric teiids (Cnemidophorus abaetensis and C. ocellifer) living sympatrically in the "restinga" habitat of AbaetΓ© in the Salvador Municipality, Bahia State, Brazil to assess the degree of niche differentiation among them. The whiptail species overlapped considerably in an hourly activity (Ojk = 0.93), in microhabitat use (Ojk = 0.97) and in the prey items consumed (Ojk = 0.89). Differences in amount of vegetation in the microhabitats used by both lizard species may have contributed to differences in the activity period and in the distribution of the main prey eaten by these lizards which may, in turn, facilitate their coexistence in AbaetΓ©. Although sympatric C. ocellifer and C. abaetensis in AbaetΓ© differed only slightly in their use of microhabitats, period of activity and diet, the most important niche dimension segregating the two species seemed to be the food niche._____________________________________________________________________________________ RESUMO: As diferenΓ§as entre espΓ©cies simpΓ‘tricas geralmente podem ser atribuΓ­das Γ s variaçáes na utilização de trΓͺs dimensΓ΅es primΓ‘rias de recurso: o perΓ­odo de atividade, o microhabitat e o alimento ou a alguma combinação das trΓͺs. No entanto, tais diferenΓ§as na utilização de recursos entre espΓ©cies simpΓ‘tricas tΓͺm sido sugeridas mais como um reflexo de suas necessidades ecolΓ³gicas especΓ­ficas do que resultado de pressΓ£o competitiva. Neste estudo, avaliou-se o nicho temporal, o espacial e o alimentar de dois teΓ­deos cogenΓ©ricos (Cnemidophorus abaetensis e C. ocellifer) vivendo em simpatria na restinga de AbaetΓ© em Salvador, Bahia. As duas espΓ©cies de lagartos sobrepΓ΅em-se consideravelmente no perΓ­odo de atividade (Ojk = 0,93), no uso dos microhabitats (Ojk = 0,97) e nos tipos de presas consumidas (Ojk = 0,89). As diferenΓ§as na quantidade de vegetação nos microhabitats utilizadas pelas duas espΓ©cies podem ter contribuΓ­do para as diferenΓ§as no perΓ­odo de atividade e na distribuição dos principais tipos de presas consumidas por estas duas espΓ©cies de lagartos, o que pode ter favorecido a coexistΓͺncia entre elas na restinga do AbaetΓ©. No entanto, as diferenΓ§as na dieta sΓ£o as mais significativas para a segregação

    Ventilatory muscle strength, diaphragm thickness and pulmonary function in world-class powerlifters.

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    Resistance training activates the ventilatory muscles providing a stimulus similar to ventilatory muscle training. We examined the effects of elite powerlifting training upon ventilatory muscle strength, pulmonary function and diaphragm thickness in world-class powerlifters (POWER) and a control group (CON) with no history of endurance or resistance training, matched for age, height and body mass

    Genome-wide DNA methylation map of human neutrophils reveals widespread inter-individual epigenetic variation

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    The extent of variation in DNA methylation patterns in healthy individuals is not yet well documented. Identification of inter-individual epigenetic variation is important for understanding phenotypic variation and disease susceptibility. Using neutrophils from a cohort of healthy individuals, we generated base-resolution DNA methylation maps to document inter-individual epigenetic variation. We identified 12851 autosomal inter-individual variably methylated fragments (iVMFs). Gene promoters were the least variable, whereas gene body and upstream regions showed higher variation in DNA methylation. The iVMFs were relatively enriched in repetitive elements compared to non-iVMFs, and were associated with genome regulation and chromatin function elements. Further, variably methylated genes were disproportionately associated with regulation of transcription, responsive function and signal transduction pathways. Transcriptome analysis indicates that iVMF methylation at differentially expressed exons has a positive correlation and local effect on the inclusion of that exon in the mRNA transcript

    Extreme Conservation Leads to Recovery of the Virunga Mountain Gorillas

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    As wildlife populations are declining, conservationists are under increasing pressure to measure the effectiveness of different management strategies. Conventional conservation measures such as law enforcement and community development projects are typically designed to minimize negative human influences upon a species and its ecosystem. In contrast, we define β€œextreme” conservation as efforts targeted to deliberately increase positive human influences, including veterinary care and close monitoring of individual animals. Here we compare the impact of both conservation approaches upon the population growth rate of the critically endangered Virunga mountain gorillas (Gorilla beringei beringei), which increased by 50% since their nadir in 1981, from approximately 250 to nearly 400 gorillas. Using demographic data from 1967–2008, we show an annual decline of 0.7%Β±0.059% for unhabituated gorillas that received intensive levels of conventional conservation approaches, versus an increase 4.1%Β±0.088% for habituated gorillas that also received extreme conservation measures. Each group of habituated gorillas is now continuously guarded by a separate team of field staff during daylight hours and receives veterinary treatment for snares, respiratory disease, and other life-threatening conditions. These results suggest that conventional conservation efforts prevented a severe decline of the overall population, but additional extreme measures were needed to achieve positive growth. Demographic stochasticity and socioecological factors had minimal impact on variability in the growth rates. Veterinary interventions could account for up to 40% of the difference in growth rates between habituated versus unhabituated gorillas, with the remaining difference likely arising from greater protection against poachers. Thus, by increasing protection and facilitating veterinary treatment, the daily monitoring of each habituated group contributed to most of the difference in growth rates. Our results argue for wider consideration of extreme measures and offer a startling view of the enormous resources that may be needed to conserve some endangered species

    Somatic sex-specific transcriptome differences in Drosophila revealed by whole transcriptome sequencing

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    <p>Abstract</p> <p>Background</p> <p>Understanding animal development and physiology at a molecular-biological level has been advanced by the ability to determine at high resolution the repertoire of mRNA molecules by whole transcriptome resequencing. This includes the ability to detect and quantify rare abundance transcripts and isoform-specific mRNA variants produced from a gene.</p> <p>The sex hierarchy consists of a pre-mRNA splicing cascade that directs the production of sex-specific transcription factors that specify nearly all sexual dimorphism. We have used deep RNA sequencing to gain insight into how the Drosophila sex hierarchy generates somatic sex differences, by examining gene and transcript isoform expression differences between the sexes in adult head tissues.</p> <p>Results</p> <p>Here we find 1,381 genes that differ in overall expression levels and 1,370 isoform-specific transcripts that differ between males and females. Additionally, we find 512 genes not regulated downstream of <it>transformer </it>that are significantly more highly expressed in males than females. These 512 genes are enriched on the Γ— chromosome and reside adjacent to dosage compensation complex entry sites, which taken together suggests that their residence on the Γ— chromosome might be sufficient to confer male-biased expression. There are no transcription unit structural features, from a set of features, that are robustly significantly different in the genes with significant sex differences in the ratio of isoform-specific transcripts, as compared to random isoform-specific transcripts, suggesting that there is no single molecular mechanism that generates isoform-specific transcript differences between the sexes, even though the sex hierarchy is known to include three pre-mRNA splicing factors.</p> <p>Conclusions</p> <p>We identify thousands of genes that show sex-specific differences in overall gene expression levels, and identify hundreds of additional genes that have differences in the abundance of isoform-specific transcripts. No transcription unit structural feature was robustly enriched in the sex-differentially expressed transcript isoforms. Additionally, we found that many genes with male-biased expression were enriched on the Γ— chromosome and reside adjacent to dosage compensation entry sites, suggesting that differences in sex chromosome composition contributes to dimorphism in gene expression. Taken together, this study provides new insight into the molecular underpinnings of sexual differentiation.</p
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