The rare-earth metal, ytterbium (Yb), was deposited on graphene grown on Si-face SiC, kept at room temperature. Yb was not found to intercalate, destroy or dope the graphene layer before subsequent heating, unlike alk...The rare-earth metal, ytterbium (Yb), was deposited on graphene grown on Si-face SiC, kept at room temperature. Yb was not found to intercalate, destroy or dope the graphene layer before subsequent heating, unlike alkali metals such as Li and Na. Our photoemission results reveal that heating to 300oC promotes Yb intercalation into the graphene-substrate interface. Real-time low energy electron microscopy (LEEM) measurements indicated intercalation to start at a sample temperature of around 220oC. In the intercalation process, Yb penetrates through the graphene and buffer layer and forms bonds to the silicon in the topmost SiC substrate bilayer, as indicated by the shifted components observed in the C 1s, Si 2p, and Yb 4f spectra. The Yb intercalation decouples the buffer layer from the substrate and transforms it into another graphene layer as manifested by the absence of buffer layer spots in the μ-LEED pattern and the appearance of an additional π band in the ARPES spectra, respectively. Moreover, the observed shift of the Dirac point down from the Fermi level by 1.9 eV indicates electron doping of the graphene layer upon Yb intercalation. The Yb intercalated graphene sample was found to be thermodynamically stable up to temperatures around 700oC.展开更多
The leafy seadragon certainly is among evolution’s most“beautiful and wonderful”species aptly named for its extraordinary camouflage mimicking its coastal seaweed habitat.However,limited information is known about ...The leafy seadragon certainly is among evolution’s most“beautiful and wonderful”species aptly named for its extraordinary camouflage mimicking its coastal seaweed habitat.However,limited information is known about the genetic basis of its phenotypes and conspicuous camouflage.Here,we revealed genomic signatures of rapid evolution and positive selection in core genes related to its camouflage,which allowed us to predict population dynamics for this species.Comparative genomic analysis revealed that seadragons have the smallest olfactory repertoires among all ray-finned fishes,suggesting adaptations to the highly specialized habitat.Other positively selected and rapidly evolving genes that serve in bone development and coloration are highly expressed in the leaf-like appendages,supporting a recent adaptive shift in camouflage appendage formation.Knock-out of bmp6 results in dysplastic intermuscular bones with a significantly reduced number in zebrafish,implying its important function in bone formation.Global climate change-induced loss of seagrass beds now severely threatens the continued existence of this enigmatic species.The leafy seadragon has a historically small population size likely due to its specific habitat requirements that further exacerbate its vulnerability to climate change.Therefore,taking climate change-induced range shifts into account while developing future protection strategies.展开更多
The uplift of the Tibetan Plateau significantly altered the geomorphology and climate of the Euroasia by creating large mountains and rivers.Fishes are more likely to be affected relative to other organisms,as they ar...The uplift of the Tibetan Plateau significantly altered the geomorphology and climate of the Euroasia by creating large mountains and rivers.Fishes are more likely to be affected relative to other organisms,as they are largely restricted to river systems.Faced with the rapidly flowing water in the Tibetan Plateau,a group of catfish has evolved greatly enlarged pectoral fins with more numbers of fin-rays to form an adhesive apparatus.However,the genetic basis of these adaptations in Tibetan catfishes remains elusive.In this study,we performed comparative genomic analyses based on the chromosome-level genome of Glyptosternum maculatum in family Sisoridae and detected some proteins with conspicuously high evolutionary rates in particular in genes involved in skeleton development,energy metabolism,and hypoxia response.We found that the hoxd12a gene evolved faster and a loss-of-function assay of hoxd12a supports a potential role for this gene in shaping the enlarged fins of these Tibetan catfishes.Other genes with amino acid replacements and signatures of positive selection included proteins involved in low temperature(TRMU)and hypoxia(VHL)responses.Functional assays reveal that the G.maculatum TRMU allele generates more mitochondrial ATP than the ancestral allele found in low-altitude fishes.Functional assays of VHL alleles suggest that the G.maculatum allele has lower transactivation activity than the low-altitude forms.These findings provide a window into the genomic underpinnings of physiological adaptations that permit G.maculatum to survive in the harsh environment of the Tibetan Himalayas that mirror those that are convergently found in other vertebrates such as humans.展开更多
Asymmetries in bilateral organisms attract a lot of curiosity given that they are conspicuous departures from the norm.They allow the investigation of the integration at different levels of biological organization.Her...Asymmetries in bilateral organisms attract a lot of curiosity given that they are conspicuous departures from the norm.They allow the investigation of the integration at different levels of biological organization.Here we study whether and how behavioral and asymmetrical anatomical traits coevolved and work together.We ask if asymmetry is determined locally for each trait or at a whole individual level in a species bearing conspicuous asymmetrical genitalia.Asymmetric genitalia evolved in many species;however,in most cases the direction of asymmetry is fixed.Therefore,it has been rarely determined if there is an association between the direction of asymmetry in genitalia and other traits.In onesided livebearer fish of the genus Jenynsia(Cyprinodontiformes,Anablepidae),the anal fin of males is modified into a gonopodium,an intromittent organ that serves to inseminate females.The gonopodium shows a conspicuous asymmetry,with its tip bending either to the left or the right.By surveying 13 natural populations of Jenynsia lineata,we found that both genital morphs are equally common in wild populations.In a series of experiments in a laboratory population,we discovered asymmetry and lateralization for multiple other traits;yet,the degree of integration varied highly among them.Lateralization in exploratory behavior in response to different stimuli was not associated with genital morphology.Interestingly,the direction of genital asymmetry was positively correlated with sidedness of mating preference and the number of neuromasts in the lateral line.This suggests integration of functionally linked asymmetric traits;however,there is no evidence that asymmetry is determined at the whole individual level in our study species.展开更多
Few fishes have evolved elevated body temperatures compared with ambient temperatures,and only in opah(Lampris spp)is the entire body affected.To understand the molecular basis of endothermy,we analyzed the opah genom...Few fishes have evolved elevated body temperatures compared with ambient temperatures,and only in opah(Lampris spp)is the entire body affected.To understand the molecular basis of endothermy,we analyzed the opah genome and identified 23 genes with convergent amino acid substitutions across fish,birds,and mammals,including slc8b1,which encodes the mitochondrial Na+/Ca2+exchanger and is essential for heart function andmetabolic heat production.Among endothermic fishes,44 convergent genes with suggestive metabolic functions were identified,such as glrx3,encoding a crucial protein for hemoglobin maturation.Numerous genes involved in the production and retention of metabolic heat were also found to be under positive selection.Analyses of opah’s unique inner-heat-producing pectoral muscle layer(PMI),an evolutionary key innovation,revealed that many proteins were co-opted from dorsal swimming muscles for thermogenesis and oxidative phosphorylation.Thus,the opah genome provides valuable resources and opportunities to uncover the genetic basis of thermal adaptations in fish.展开更多
文摘The rare-earth metal, ytterbium (Yb), was deposited on graphene grown on Si-face SiC, kept at room temperature. Yb was not found to intercalate, destroy or dope the graphene layer before subsequent heating, unlike alkali metals such as Li and Na. Our photoemission results reveal that heating to 300oC promotes Yb intercalation into the graphene-substrate interface. Real-time low energy electron microscopy (LEEM) measurements indicated intercalation to start at a sample temperature of around 220oC. In the intercalation process, Yb penetrates through the graphene and buffer layer and forms bonds to the silicon in the topmost SiC substrate bilayer, as indicated by the shifted components observed in the C 1s, Si 2p, and Yb 4f spectra. The Yb intercalation decouples the buffer layer from the substrate and transforms it into another graphene layer as manifested by the absence of buffer layer spots in the μ-LEED pattern and the appearance of an additional π band in the ARPES spectra, respectively. Moreover, the observed shift of the Dirac point down from the Fermi level by 1.9 eV indicates electron doping of the graphene layer upon Yb intercalation. The Yb intercalated graphene sample was found to be thermodynamically stable up to temperatures around 700oC.
基金supported by the National Natural Science Foundation of China (41825013,42230409,42006108,42276126)Key Research Program of Frontier Sciences of CAS (ZDBS-LY-DQC004)+2 种基金the National Key Research and Development Program of China (2021YFF0502803)Strategic Priority Research Program of the Chinese Academy of Sciences (XDB42030204)South China Sea Institute of Oceanology of the Chinese Academy of Sciences (SCSIO202208)。
文摘The leafy seadragon certainly is among evolution’s most“beautiful and wonderful”species aptly named for its extraordinary camouflage mimicking its coastal seaweed habitat.However,limited information is known about the genetic basis of its phenotypes and conspicuous camouflage.Here,we revealed genomic signatures of rapid evolution and positive selection in core genes related to its camouflage,which allowed us to predict population dynamics for this species.Comparative genomic analysis revealed that seadragons have the smallest olfactory repertoires among all ray-finned fishes,suggesting adaptations to the highly specialized habitat.Other positively selected and rapidly evolving genes that serve in bone development and coloration are highly expressed in the leaf-like appendages,supporting a recent adaptive shift in camouflage appendage formation.Knock-out of bmp6 results in dysplastic intermuscular bones with a significantly reduced number in zebrafish,implying its important function in bone formation.Global climate change-induced loss of seagrass beds now severely threatens the continued existence of this enigmatic species.The leafy seadragon has a historically small population size likely due to its specific habitat requirements that further exacerbate its vulnerability to climate change.Therefore,taking climate change-induced range shifts into account while developing future protection strategies.
基金supported by the Strategic Priority Research Program of Chinese Academy of Sciences(XDB31000000)the National Natural Science Foundation of China(32170480,31972866,31702016,31601858,32022009)+5 种基金Chinese Academy of Sciences(Youth Innovation Promotion Association),Chinese Academy of Sciences(http://www.yicas.cn)the Pioneer Hundred Talents Program,and ZDBS-LYSM005)the Second Tibetan Plateau Scientific Expedition and Research Program(STEP,2019QZKK0501)State Key Laboratory of Genetic Resources and Evolution,Kunming Institute of Zoology,Chinese Academy of Sciences(GREKF21-04)the Young Top-notch Talent Cultivation Program of Hubei Provincesupported by the Wuhan Branch,Supercomputing Center,Chinese Academy of Sciences,China。
文摘The uplift of the Tibetan Plateau significantly altered the geomorphology and climate of the Euroasia by creating large mountains and rivers.Fishes are more likely to be affected relative to other organisms,as they are largely restricted to river systems.Faced with the rapidly flowing water in the Tibetan Plateau,a group of catfish has evolved greatly enlarged pectoral fins with more numbers of fin-rays to form an adhesive apparatus.However,the genetic basis of these adaptations in Tibetan catfishes remains elusive.In this study,we performed comparative genomic analyses based on the chromosome-level genome of Glyptosternum maculatum in family Sisoridae and detected some proteins with conspicuously high evolutionary rates in particular in genes involved in skeleton development,energy metabolism,and hypoxia response.We found that the hoxd12a gene evolved faster and a loss-of-function assay of hoxd12a supports a potential role for this gene in shaping the enlarged fins of these Tibetan catfishes.Other genes with amino acid replacements and signatures of positive selection included proteins involved in low temperature(TRMU)and hypoxia(VHL)responses.Functional assays reveal that the G.maculatum TRMU allele generates more mitochondrial ATP than the ancestral allele found in low-altitude fishes.Functional assays of VHL alleles suggest that the G.maculatum allele has lower transactivation activity than the low-altitude forms.These findings provide a window into the genomic underpinnings of physiological adaptations that permit G.maculatum to survive in the harsh environment of the Tibetan Himalayas that mirror those that are convergently found in other vertebrates such as humans.
基金This work was supported by the Deutsche Forschungsgemeinschaft,Grant Number TO914/2-1 to J.T-D.
文摘Asymmetries in bilateral organisms attract a lot of curiosity given that they are conspicuous departures from the norm.They allow the investigation of the integration at different levels of biological organization.Here we study whether and how behavioral and asymmetrical anatomical traits coevolved and work together.We ask if asymmetry is determined locally for each trait or at a whole individual level in a species bearing conspicuous asymmetrical genitalia.Asymmetric genitalia evolved in many species;however,in most cases the direction of asymmetry is fixed.Therefore,it has been rarely determined if there is an association between the direction of asymmetry in genitalia and other traits.In onesided livebearer fish of the genus Jenynsia(Cyprinodontiformes,Anablepidae),the anal fin of males is modified into a gonopodium,an intromittent organ that serves to inseminate females.The gonopodium shows a conspicuous asymmetry,with its tip bending either to the left or the right.By surveying 13 natural populations of Jenynsia lineata,we found that both genital morphs are equally common in wild populations.In a series of experiments in a laboratory population,we discovered asymmetry and lateralization for multiple other traits;yet,the degree of integration varied highly among them.Lateralization in exploratory behavior in response to different stimuli was not associated with genital morphology.Interestingly,the direction of genital asymmetry was positively correlated with sidedness of mating preference and the number of neuromasts in the lateral line.This suggests integration of functionally linked asymmetric traits;however,there is no evidence that asymmetry is determined at the whole individual level in our study species.
基金supported by the Key ResearchProgramof Frontier Sciences ofCAS(ZDBS-LY-DQC004)the Special Foundation for National Science and Technology Basic Research Program of China(2018FY100100)+4 种基金the National Natural Science Foundation of China(41825013)the Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou)(GML2019ZD0407)the Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou)(GML2019ZD0401)the Guangdong Special Support Program of Leading Scientific and Technological Innovation(2017 T X04N442)the Grants by the German Science Foundation(DFG)。
文摘Few fishes have evolved elevated body temperatures compared with ambient temperatures,and only in opah(Lampris spp)is the entire body affected.To understand the molecular basis of endothermy,we analyzed the opah genome and identified 23 genes with convergent amino acid substitutions across fish,birds,and mammals,including slc8b1,which encodes the mitochondrial Na+/Ca2+exchanger and is essential for heart function andmetabolic heat production.Among endothermic fishes,44 convergent genes with suggestive metabolic functions were identified,such as glrx3,encoding a crucial protein for hemoglobin maturation.Numerous genes involved in the production and retention of metabolic heat were also found to be under positive selection.Analyses of opah’s unique inner-heat-producing pectoral muscle layer(PMI),an evolutionary key innovation,revealed that many proteins were co-opted from dorsal swimming muscles for thermogenesis and oxidative phosphorylation.Thus,the opah genome provides valuable resources and opportunities to uncover the genetic basis of thermal adaptations in fish.