The Experts below are selected from a list of 297 Experts worldwide ranked by ideXlab platform
Harald Schneider - One of the best experts on this subject based on the ideXlab platform.
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the timescale of early land Plant Evolution
Proceedings of the National Academy of Sciences of the United States of America, 2018Co-Authors: Jennifer L Morris, Mark N Puttick, James W Clark, Dianne Edwards, Paul Kenrick, Silvia Pressel, Charles H Wellman, Ziheng Yang, Harald SchneiderAbstract:Establishing the timescale of early land Plant Evolution is essential for testing hypotheses on the coEvolution of land Plants and Earth's System. The sparseness of early land Plant megafossils and stratigraphic controls on their distribution make the fossil record an unreliable guide, leaving only the molecular clock. However, the application of molecular clock methodology is challenged by the current impasse in attempts to resolve the Evolutionary relationships among the living bryophytes and tracheophytes. Here, we establish a timescale for early land Plant Evolution that integrates over topological uncertainty by exploring the impact of competing hypotheses on bryophyte-tracheophyte relationships, among other variables, on divergence time estimation. We codify 37 fossil calibrations for ViridiPlantae following best practice. We apply these calibrations in a Bayesian relaxed molecular clock analysis of a phylogenomic dataset encompassing the diversity of Embryophyta and their relatives within ViridiPlantae. Topology and dataset sizes have little impact on age estimates, with greater differences among alternative clock models and calibration strategies. For all analyses, a Cambrian origin of Embryophyta is recovered with highest probability. The estimated ages for crown tracheophytes range from Late Ordovician to late Silurian. This timescale implies an early establishment of terrestrial ecosystems by land Plants that is in close accord with recent estimates for the origin of terrestrial animal lineages. Biogeochemical models that are constrained by the fossil record of early land Plants, or attempt to explain their impact, must consider the implications of a much earlier, middle Cambrian-Early Ordovician, origin.
Ziheng Yang - One of the best experts on this subject based on the ideXlab platform.
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the timescale of early land Plant Evolution
Proceedings of the National Academy of Sciences of the United States of America, 2018Co-Authors: Jennifer L Morris, Mark N Puttick, James W Clark, Dianne Edwards, Paul Kenrick, Silvia Pressel, Charles H Wellman, Ziheng Yang, Harald SchneiderAbstract:Establishing the timescale of early land Plant Evolution is essential for testing hypotheses on the coEvolution of land Plants and Earth's System. The sparseness of early land Plant megafossils and stratigraphic controls on their distribution make the fossil record an unreliable guide, leaving only the molecular clock. However, the application of molecular clock methodology is challenged by the current impasse in attempts to resolve the Evolutionary relationships among the living bryophytes and tracheophytes. Here, we establish a timescale for early land Plant Evolution that integrates over topological uncertainty by exploring the impact of competing hypotheses on bryophyte-tracheophyte relationships, among other variables, on divergence time estimation. We codify 37 fossil calibrations for ViridiPlantae following best practice. We apply these calibrations in a Bayesian relaxed molecular clock analysis of a phylogenomic dataset encompassing the diversity of Embryophyta and their relatives within ViridiPlantae. Topology and dataset sizes have little impact on age estimates, with greater differences among alternative clock models and calibration strategies. For all analyses, a Cambrian origin of Embryophyta is recovered with highest probability. The estimated ages for crown tracheophytes range from Late Ordovician to late Silurian. This timescale implies an early establishment of terrestrial ecosystems by land Plants that is in close accord with recent estimates for the origin of terrestrial animal lineages. Biogeochemical models that are constrained by the fossil record of early land Plants, or attempt to explain their impact, must consider the implications of a much earlier, middle Cambrian-Early Ordovician, origin.
Jennifer L Morris - One of the best experts on this subject based on the ideXlab platform.
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the timescale of early land Plant Evolution
Proceedings of the National Academy of Sciences of the United States of America, 2018Co-Authors: Jennifer L Morris, Mark N Puttick, James W Clark, Dianne Edwards, Paul Kenrick, Silvia Pressel, Charles H Wellman, Ziheng Yang, Harald SchneiderAbstract:Establishing the timescale of early land Plant Evolution is essential for testing hypotheses on the coEvolution of land Plants and Earth's System. The sparseness of early land Plant megafossils and stratigraphic controls on their distribution make the fossil record an unreliable guide, leaving only the molecular clock. However, the application of molecular clock methodology is challenged by the current impasse in attempts to resolve the Evolutionary relationships among the living bryophytes and tracheophytes. Here, we establish a timescale for early land Plant Evolution that integrates over topological uncertainty by exploring the impact of competing hypotheses on bryophyte-tracheophyte relationships, among other variables, on divergence time estimation. We codify 37 fossil calibrations for ViridiPlantae following best practice. We apply these calibrations in a Bayesian relaxed molecular clock analysis of a phylogenomic dataset encompassing the diversity of Embryophyta and their relatives within ViridiPlantae. Topology and dataset sizes have little impact on age estimates, with greater differences among alternative clock models and calibration strategies. For all analyses, a Cambrian origin of Embryophyta is recovered with highest probability. The estimated ages for crown tracheophytes range from Late Ordovician to late Silurian. This timescale implies an early establishment of terrestrial ecosystems by land Plants that is in close accord with recent estimates for the origin of terrestrial animal lineages. Biogeochemical models that are constrained by the fossil record of early land Plants, or attempt to explain their impact, must consider the implications of a much earlier, middle Cambrian-Early Ordovician, origin.
J Peter Gogarten - One of the best experts on this subject based on the ideXlab platform.
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Concerted gene recruitment in early Plant Evolution
Genome Biology, 2008Co-Authors: Jinling Huang, J Peter GogartenAbstract:Background Horizontal gene transfer occurs frequently in prokaryotes and unicellular eukaryotes. Anciently acquired genes, if retained among descendants, might significantly affect the long-term Evolution of the recipient lineage. However, no systematic studies on the scope of anciently acquired genes and their impact on macroEvolution are currently available in eukaryotes. Results Analyses of the genome of the red alga Cyanidioschyzon identified 37 genes that were acquired from non-organellar sources prior to the split of red algae and green Plants. Ten of these genes are rarely found in cyanobacteria or have additional plastid-derived homologs in Plants. These genes most likely provided new functions, often essential for Plant growth and development, to the ancestral Plant. Many remaining genes may represent replacements of endogenous homologs with a similar function. Furthermore, over 78% of the anciently acquired genes are related to the biogenesis and functionality of plastids, the defining character of Plants. Conclusion Our data suggest that, although ancient horizontal gene transfer events did occur in eukaryotic Evolution, the number of acquired genes does not predict the role of horizontal gene transfer in the adaptation of the recipient organism. Our data also show that multiple independently acquired genes are able to generate and optimize key Evolutionary novelties in major eukaryotic groups. In light of these findings, we propose and discuss a general mechanism of horizontal gene transfer in the macroEvolution of eukaryotes.
Daisaku Ohta - One of the best experts on this subject based on the ideXlab platform.
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diversification of p450 genes during land Plant Evolution
Annual Review of Plant Biology, 2010Co-Authors: Masaharu Mizutani, Daisaku OhtaAbstract:Plant cytochromes P450 (P450s) catalyze a wide variety of monooxygenation/hydroxylation reactions in primary and secondary metabolism. The number of P450 genes in Plant genomes is estimated to be up to 1% of total gene annotations of each Plant species. This implies that diversification within P450 gene superfamilies has led to the emergence of new metabolic pathways throughout land Plant Evolution. The conserved P450 families contribute to chemical defense mechanisms under terrestrial conditions and several are involved in hormone biosynthesis and catabolism. Species-specific P450 families are essential for the biosynthetic pathways of species-specialized metabolites. Future genome-wide analyses of P450 gene clusters and coexpression networks should help both in identifying the functions of many orphan P450s and in understanding the Evolution of this versatile group of enzymes.
