Project description:<p>The biogeography of tropical Andean plants and the effects of altitudinal barriers as evolutionary constraints have been the focus of great debate. Although genetic markers have provided evidence for the geographic isolation of Andean-endemic groups, even highly variable molecular markers commonly used to assess biogeography do not have the resolving power needed for a fine geographic discrimination in some Andean taxa. We present a metabolomics approach based on ultrahigh-performance liquid chromatography-mass spectrometry combined with multivariate statistical methods and machine learning algorithms of multiple species and populations of Espeletiinae (Asteraceae) to provide metabolomic evidence for biogeographic segregation in this Andean-endemic subtribe. Our approach allows the discrimination of Espeletiinae taxa at different geographic scales with characteristic metabolic fingerprints related to their country of origin on a global scale, to their páramo massifs on a regional scale and to their páramo complexes on a local scale, revealing inter- and intraspecific metabolic variations. Our results, together with previous studies, suggest that Andean geography and Pleistocene glacial cycles not only shaped the evolutionary history of Espeletiinae but also its metabolic fingerprints, demonstrating the potential of metabolomics for understanding biogeographic patterns in recently diversified plant groups where genetic divergence is still at an early stage.</p><p><br></p><p><strong>Intraspecific chemical variability assay</strong> protocols and data are reported in the current study <a href='https://www.ebi.ac.uk/metabolights/MTBLS943' rel='noopener noreferrer' target='_blank'><strong>MTBLS943</strong></a>.</p><p>I<strong>nterspecific chemical variability assay</strong> protocols and data are reported in study <a href='https://www.ebi.ac.uk/metabolights/MTBLS944' rel='noopener noreferrer' target='_blank'><strong>MTBLS944</strong></a>.</p>
Project description:<p>The biogeography of tropical Andean plants and the effects of altitudinal barriers as evolutionary constraints have been the focus of great debate. Although genetic markers have provided evidence for the geographic isolation of Andean-endemic groups, even highly variable molecular markers commonly used to assess biogeography do not have the resolving power needed for a fine geographic discrimination in some Andean taxa. We present a metabolomics approach based on ultrahigh-performance liquid chromatography-mass spectrometry combined with multivariate statistical methods and machine learning algorithms of multiple species and populations of Espeletiinae (Asteraceae) to provide metabolomic evidence for biogeographic segregation in this Andean-endemic subtribe. Our approach allows the discrimination of Espeletiinae taxa at different geographic scales with characteristic metabolic fingerprints related to their country of origin on a global scale, to their páramo massifs on a regional scale and to their páramo complexes on a local scale, revealing inter- and intraspecific metabolic variations. Our results, together with previous studies, suggest that Andean geography and Pleistocene glacial cycles not only shaped the evolutionary history of Espeletiinae but also its metabolic fingerprints, demonstrating the potential of metabolomics for understanding biogeographic patterns in recently diversified plant groups where genetic divergence is still at an early stage.</p><p><br></p><p><strong>Interspecific chemical variability assay</strong> protocols and data are reported in the current study <a href='https://www.ebi.ac.uk/metabolights/MTBLS944' rel='noopener noreferrer' target='_blank'><strong>MTBLS944</strong></a>.</p><p><strong>Intraspecific chemical variability assay</strong> protocols and data are reported in study <a href='https://www.ebi.ac.uk/metabolights/MTBLS943' rel='noopener noreferrer' target='_blank'><strong>MTBLS943</strong></a>.</p>
Project description:Understanding biological diversity and distribution patterns at multiple spatial scales is a central issue in ecology. Here, we investigated the biogeographical patterns of functional genes in soil microbes from 24 arctic heath sites using GeoChip-based metagenomics and principal coordinates of neighbour matrices (PCNM)-based analysis. Functional gene richness varied considerably among sites, while the proportions of each major functional gene category were evenly distributed. Functional gene composition varied significantly at most medium and broad spatial scales, and the PCNM analyses indicated that 14-20% of the variation in total and major functional gene categories could be attributed primarily to relatively broad-scale spatial effects that were consistent with broad-scale variation in soil pH and total nitrogen. The combination of variance partitioning and multi-scales analysis indicated that spatial distance effects contributed 12% to variation in functional gene composition,whereas environmental factors contributed only 3%. This relatively strong influence of spatial as compared to environmental variation in determining functional gene distributions contrasts sharply with typical microbial phylotype/species-based biogeographical patterns in the Arctic and elsewhere. Our results suggest that the distributions of soil functional genes cannot be predicted from phylogenetic distributions because spatial factors associated with historical contingencies are relatively important determinants of their biogeography.
Project description:Birds and other reptiles possess a diversity of feather and scale-like skin appendages. Feathers are commonly assumed to have originated from ancestral scales in theropod dinosaurs. However, most birds also have scaled feet, indicating birds evolved the capacity to grow both ancestral and derived morphologies. This suggests a more complex evolutionary history than a simple linear transition between feathers and scales. We set out to investigate the evolution of feathers via the comparison of transcriptomes assembled from diverse skin appendages in chicken, emu, and alligator. Our data reveal that feathers and the overlapping ‘scutate’ scales of birds share more similar gene expression to each other, and to two types of alligator scales, than they do to the tuberculate ‘reticulate’ scales on bird footpads. Accordingly, we propose a history of skin appendage diversification, in which feathers and bird scutate scales arose from ancestral archosaur body scales, whereas reticulate scales arose earlier in tetrapod evolution. We also show that many “feather-specific genes” are also expressed in alligator scales. In-situ hybridization results in feather buds suggest that these genes represent ancestral scale genes that acquired novel roles in feather morphogenesis and were repressed in bird scales. Our findings suggest that the differential reuse, in feathers, and suppression, in bird scales, of genes ancestrally expressed in archosaur scales has been a key factor in the origin of feathers – and may represent an important mechanism for the origin of evolutionary novelties.
Project description:Spatial patterns of gene expression span many scales, and are shaped by both local (e.g. cell-cell interactions) and global (e.g. tissue, organ) context. However, most in situ methods for profiling gene expression either average local contexts or are restricted to limited fields of view. Here we introduce sci-Space, a scale-flexible method that retains single cell resolution while resolving spatial heterogeneity in gene expression at larger scales. As a proof-of-concept, we apply sci-Space to the developing mouse embryo (E14), capturing the approximate spatial coordinates of profiled cells from whole embryo serial sections.
2021-07-01 | GSE166692 | GEO
Project description:Hydraulic controls of Nitrogen uptake across spatial scales
Project description:Understanding the topological configurations of chromatin can reveal valuable insights into how the genome and epigenome act in concert to control cell fate during development. Here we generate high-resolution architecture maps across seven genomic loci in embryonic stem cells and neural progenitor cells. We observe a hierarchy of 3-D interactions that undergo marked reorganization at the sub-Mb scale during differentiation. Distinct combinations of CTCF, Mediator, and cohesin show widespread enrichment in architecture at different length scales. CTCF/cohesin anchor long-range constitutive interactions that might form the topological basis for invariant sub-domains. Conversely, Mediator/cohesin together with pioneer factors bridge short-range enhancer-promoter interactions within and between larger sub-domains. Knockdown of Smc1 or Med12 in ES cells results in disruption of spatial architecture and down-regulation of genes found in cohesin-mediated interactions. We conclude that cell type-specific chromatin organization occurs at the sub-Mb scale and that architectural proteins shape the genome in hierarchical length scales. Analysis of higher-order chromatin chromatin architecture in mouse ES cells and ES-derived NPCs. Analysis of CTCF and Smc1 occupied sites in ES-derived NPCs.