The End-Permian mass extinction(EPME),Earth’s most severe biocrisis,occurred proximal to the Permian-Triassic Boundary(PTB),with marine ecosystems experiencing catastrophic collapse.This study employs stable carbon(...The End-Permian mass extinction(EPME),Earth’s most severe biocrisis,occurred proximal to the Permian-Triassic Boundary(PTB),with marine ecosystems experiencing catastrophic collapse.This study employs stable carbon(δ^(13)C)and oxygen isotopes from marine carbonates in the Haidai Section(Xuanwei,northeastern Yunnan)to decipher paleoenvironmental drivers.The well-preserved stratigraphic sequence encompasses the Upper Permian(Yangxin and Xuanwei Formations)transitioning into the Lower Triassic(Feixianguan and Jialingjiang Formations),providing a continuous marine sedimentary archive.A marked negativeδ^(13)C excursion(-9.66‰V-PDB)occurs at the PTB,initiating from+0.82‰with subsequent gradual recovery.This geochemical signature correlates with:90%reduction in primary productivity Biodiversity collapse exhibiting cluster extinction patterns Prolonged suppression of ecological recovery Concurrently,reconstructed seawater temperatures reveal extreme thermal fluctuations,surging from 23℃to 32℃at the PTB before precipitously declining to 16℃.These perturbations demonstrate coupled biogeochemical dynamics wherein:•Carbon cycle destabilization disrupted nutrient fluxes.•Temperature oscillations exceeded marine taxa thermal tolerances.•Synergistic environmental stresses amplified extinction selectivity.Theδ^(13)C-temperature covariance(r^(2)=0.085)establishes mechanistic linkages between physicochemical perturbations and biotic responses.Our findings demonstrate that the EPME was driven by positive feedback loops in which:Volcanic CO₂emissions triggered carbonate saturation decline Thermal stratification exacerbated anoxia Biogeochemical cycling perturbations suppressed primary producers This integrated geochemical record from the Haidai Section provides critical insights into environment-organism coevolution during Phanerozoic Earth’s most profound mass extinction.展开更多
Primordial germ cells(PGCs)are the precursors of germline that are specified at the embryonic stage.Recent studies reveal that humans employ different mechanisms for PGC specification compared with model organisms suc...Primordial germ cells(PGCs)are the precursors of germline that are specified at the embryonic stage.Recent studies reveal that humans employ different mechanisms for PGC specification compared with model organisms such as mice.Moreover,the specific regulatory machinery remains largely unexplored,mainly due to the inaccessible nature of this complex biological process in humans.Here,we curate and integrate multi-omics data,including 581 RNA-seq,54 ATAC-seq,45 ChIP-seq,and 69 single-cell RNA-seq samples from different stages of human PGC development to recapitulate the precisely controlled and stepwise process,presenting an atlas in the human PGC database(hPGCdb).With these uniformly processed data and integrated analyses,we characterize the potential key transcription factors and regulatory networks governing human germ cell fate.We validate the important roles of some of the key factors in germ cell development by CRISPRi knockdown.We also identify the soma-germline interaction network and discover the involvement of SDC2 and LAMA4 for PGC development,as well as soma-derived NOTCH2 signaling for germ cell differentiation.Taken together,we have built a database for human PGCs(http://43.131.248.15:6882)and demonstrate that hPGCdb enables the identification of the missing pieces of mechanisms governing germline development,including both intrinsic and extrinsic regulatory programs.展开更多
基金supported by the Scientific Research Fund of the Education Department of Yunnan Province(Grant Number:2019J0488).
文摘The End-Permian mass extinction(EPME),Earth’s most severe biocrisis,occurred proximal to the Permian-Triassic Boundary(PTB),with marine ecosystems experiencing catastrophic collapse.This study employs stable carbon(δ^(13)C)and oxygen isotopes from marine carbonates in the Haidai Section(Xuanwei,northeastern Yunnan)to decipher paleoenvironmental drivers.The well-preserved stratigraphic sequence encompasses the Upper Permian(Yangxin and Xuanwei Formations)transitioning into the Lower Triassic(Feixianguan and Jialingjiang Formations),providing a continuous marine sedimentary archive.A marked negativeδ^(13)C excursion(-9.66‰V-PDB)occurs at the PTB,initiating from+0.82‰with subsequent gradual recovery.This geochemical signature correlates with:90%reduction in primary productivity Biodiversity collapse exhibiting cluster extinction patterns Prolonged suppression of ecological recovery Concurrently,reconstructed seawater temperatures reveal extreme thermal fluctuations,surging from 23℃to 32℃at the PTB before precipitously declining to 16℃.These perturbations demonstrate coupled biogeochemical dynamics wherein:•Carbon cycle destabilization disrupted nutrient fluxes.•Temperature oscillations exceeded marine taxa thermal tolerances.•Synergistic environmental stresses amplified extinction selectivity.Theδ^(13)C-temperature covariance(r^(2)=0.085)establishes mechanistic linkages between physicochemical perturbations and biotic responses.Our findings demonstrate that the EPME was driven by positive feedback loops in which:Volcanic CO₂emissions triggered carbonate saturation decline Thermal stratification exacerbated anoxia Biogeochemical cycling perturbations suppressed primary producers This integrated geochemical record from the Haidai Section provides critical insights into environment-organism coevolution during Phanerozoic Earth’s most profound mass extinction.
基金supported by the National Natural Science Foundation of China awarded to D.C.(32270835)Zhejiang Natural Science Foundation awarded to D.C.(Z22C129553)Dr.Li Dak Sum&Yip Yio Chin Development Fund for Regenerative Medicine,Zhejiang University,awarded to D.C.
文摘Primordial germ cells(PGCs)are the precursors of germline that are specified at the embryonic stage.Recent studies reveal that humans employ different mechanisms for PGC specification compared with model organisms such as mice.Moreover,the specific regulatory machinery remains largely unexplored,mainly due to the inaccessible nature of this complex biological process in humans.Here,we curate and integrate multi-omics data,including 581 RNA-seq,54 ATAC-seq,45 ChIP-seq,and 69 single-cell RNA-seq samples from different stages of human PGC development to recapitulate the precisely controlled and stepwise process,presenting an atlas in the human PGC database(hPGCdb).With these uniformly processed data and integrated analyses,we characterize the potential key transcription factors and regulatory networks governing human germ cell fate.We validate the important roles of some of the key factors in germ cell development by CRISPRi knockdown.We also identify the soma-germline interaction network and discover the involvement of SDC2 and LAMA4 for PGC development,as well as soma-derived NOTCH2 signaling for germ cell differentiation.Taken together,we have built a database for human PGCs(http://43.131.248.15:6882)and demonstrate that hPGCdb enables the identification of the missing pieces of mechanisms governing germline development,including both intrinsic and extrinsic regulatory programs.
