xCell Digitally portraying the tissue cellular heterogeneity landscape, bioRxiv, 2017-03-07
AbstractTissues are complex milieu consisting of numerous cell-types. Numerous recent methods attempt to enumerate cell subsets from transcriptomes. However, available method used limited source for training and displayed only partial portrayal of the full cellular landscape. Here we present xCell, a novel gene-signature based method for inferring 64 immune and stroma cell-types. We harmonized 1,822 pure human cell-types transcriptomes from various sources, employed curve fitting approach for linear comparison of cell-types, and introduced a novel spillover compensation technique for separating between cell-types. Using extensive in silico analyses and comparison to cytometry immunophenotyping we show that xCell outperforms other methods <jatsext-link xmlnsxlink=httpwww.w3.org1999xlink ext-link-type=uri xlinkhref=httpxCell.ucsf.edu>httpxCell.ucsf.edu<jatsext-link>.
biorxiv bioinformatics 0-100-users 2017The Genetic History of Northern Europe, bioRxiv, 2017-03-04
Recent ancient DNA studies have revealed that the genetic history of modern Europeans was shaped by a series of migration and admixture events between deeply diverged groups. While these events are well described in Central and Southern Europe, genetic evidence from Northern Europe surrounding the Baltic Sea is still sparse. Here we report genome-wide DNA data from 24 ancient North Europeans ranging from ~7,500 to 200 calBCE spanning the transition from a hunter-gatherer to an agricultural lifestyle, as well as the adoption of bronze metallurgy. We show that Scandinavia was settled after the retreat of the glacial ice sheets from a southern and a northern route, and that the first Scandinavian Neolithic farmers derive their ancestry from Anatolia 1000 years earlier than previously demonstrated. The range of Western European Mesolithic hunter-gatherers extended to the east of the Baltic Sea, where these populations persisted without gene-flow from Central European farmers until around 2,900 calBCE when the arrival of steppe pastoralists introduced a major shift in economy and established wide-reaching networks of contact within the Corded Ware Complex.
biorxiv genetics 0-100-users 2017Comparative genomics of the tardigrades Hypsibius dujardini and Ramazzottius varieornatus, bioRxiv, 2017-03-02
ABSTRACTTardigrada, a phylum of meiofaunal organisms, have been at the center of discussions of the evolution of Metazoa, the biology of survival in extreme environments, and the role of horizontal gene transfer in animal evolution. Tardigrada are placed as sisters to Arthropoda and Onychophora (velvet worms) in the superphylum Ecdysozoa by morphological analyses, but many molecular phylogenies fail to recover this relationship. This tension between molecular and morphological understanding may be very revealing of the mode and patterns of evolution of major groups. Similar to bdelloid rotifers, nematodes and other animals of the water film, limno-terrestrial tardigrades display extreme cryptobiotic abilities, including anhydrobiosis and cryobiosis. These extremophile behaviors challenge understanding of normal, aqueous physiology how does a multicellular organism avoid lethal cellular collapse in the absence of liquid water? Meiofaunal species have been reported to have elevated levels of HGT events, but how important this is in evolution, and in particular in the evolution of extremophile physiology, is unclear. To address these questions, we resequenced and reassembled the genome of Hypsibius dujardini, a limno-terrestrial tardigrade that can undergo anhydrobiosis only after extensive pre-exposure to drying conditions, and compared it to the genome of Ramazzottius varieornatus, a related species with tolerance to rapid desiccation. The two species had contrasting gene expression responses to anhydrobiosis, with major transcriptional change in H. dujardini but limited regulation in R. varieornatus. We identified few horizontally transferred genes, but some of these were shown to be involved in entry into anhydrobiosis. Whole-genome molecular phylogenies supported a Tardigrada+Nematoda relationship over Tardigrada+Arthropoda, but rare genomic changes tended to support Tardigrada+Arthropoda.
biorxiv genomics 0-100-users 2017Analyzing ecological networks of species interactions, bioRxiv, 2017-03-01
Networks provide one of the best representations for ecological communities, composed of many species with sometimes complex connections between them. Yet the methodological literature allowing one to analyze and extract meaning from ecological networks is dense, fragmented, and unwelcoming. We provide a general overview to the field of using networks in community ecology, outlining both the intent of the different measures, their assumptions, and the contexts in which they can be used. When methodologically justified, we suggest good practices to use in the analysis of ecological networks. We anchor this synopsis with examples from empirical studies, and conclude by highlighting what identified as needed future developments in the field.
biorxiv ecology 0-100-users 2017Enabling cross-study analysis of RNA-Sequencing data, bioRxiv, 2017-02-28
AbstractDriven by the recent advances of next generation sequencing (NGS) technologies and an urgent need to decode complex human diseases, a multitude of large-scale studies were conducted recently that have resulted in an unprecedented volume of whole transcriptome sequencing (RNA-seq) data. While these data offer new opportunities to identify the mechanisms underlying disease, the comparison of data from different sources poses a great challenge, due to differences in sample and data processing. Here, we present a pipeline that processes and unifies RNA-seq data from different studies, which includes uniform realignment and gene expression quantification as well as batch effect removal. We find that uniform alignment and quantification is not sufficient when combining RNA-seq data from different sources and that the removal of other batch effects is essential to facilitate data comparison. We have processed data from the Genotype Tissue Expression project (GTEx) and The Cancer Genome Atlas (TCGA) and have successfully corrected for study-specific biases, enabling comparative analysis across studies. The normalized data are available for download via GitHub (at <jatsext-link xmlnsxlink=httpwww.w3.org1999xlink ext-link-type=uri xlinkhref=httpsgithub.commskccRNAseqDB>httpsgithub.commskccRNAseqDB<jatsext-link>).
biorxiv bioinformatics 0-100-users 2017Multiplexed confocal and super-resolution fluorescence imaging of cytoskeletal and neuronal synapse proteins, bioRxiv, 2017-02-26
ABSTRACTNeuronal synapses contain dozens of protein species whose expression levels and localizations are key determinants of synaptic transmission and plasticity. The spectral properties of fluorophores used in conventional microscopy limit the number of measured proteins to four species within a given sample. The ability to perform high-throughput confocal or super-resolution imaging of many proteins simultaneously without limitation in target number imposed by this spectral limit would enable large-scale characterization of synaptic protein networks in situ. Here, we introduce PRISM Probe-based Imaging for Sequential Multiplexing, a method that sequentially utilizes either high affinity Locked Nucleic Acid (LNA) or low affinity DNA probes to enable diffraction-limited confocal and PAINT-based super-resolution imaging. High-affinity LNA probes offer high-throughput, confocal-based imaging compared with PAINT, which uses low affinity probes to realize localization-based super-resolution imaging. Simultaneous immunostaining of all targets is performed prior to imaging, followed by sequential LNADNA probe exchange that requires only minutes under mild wash conditions. We apply PRISM to quantify the co-expression levels and nanometer-scale organization of one dozen cytoskeletal and synaptic proteins within individual neuronal synapses. Our approach is scalable to dozens of target proteins and is compatible with high-content screening platforms commonly used to interrogate phenotypic changes associated with genetic and drug perturbations in a variety of cell types.
biorxiv bioengineering 0-100-users 2017