[Objective] The aim of this study was to reveal the relationship between inihibin (INH) α precursor gene and seasonal reproduction of goats, and investigate the evolutionary conservation of INHα precursor gene. [ ...[Objective] The aim of this study was to reveal the relationship between inihibin (INH) α precursor gene and seasonal reproduction of goats, and investigate the evolutionary conservation of INHα precursor gene. [ Method] Cloning and sequence analysis of 5' flanking region and exon of inihibinα (INHE) precursor gene in twenty ewes between non-seasonal estrous breed (Haimen goats) and seasonal estrous breed (Anhui white goats) was analyzed in this study. [ Result] Compared with Anhui white goats, INHα precursor gene in Haimen goats had three SNP but no amino acid change, while its nucleotide homology was 99.7% and amino acid homology was 100%. The nucleotide homology of INHα precursor gene in goat, cattle, pig, person, chicken, horse, rat and dog ranged from 12.7% to 96.5%. [ Conclusion] INHα precursor gene tends to be highly conserved in species, and any change of nucleotide and amino acid maybe directly influence the function of the whole gene coding and regulation.展开更多
[Objective] The study aimed at cloning and identifying the toll receptor gene 9(TLR9) of wild Ovis ammon in Xinjiang,and predicting its structure and function.[Method] The TLR9 complete sequence of wild Ovis ammon w...[Objective] The study aimed at cloning and identifying the toll receptor gene 9(TLR9) of wild Ovis ammon in Xinjiang,and predicting its structure and function.[Method] The TLR9 complete sequence of wild Ovis ammon was cloned from its peripheral blood by PCR technology.Then the PCR products were purified by agarose gel electrophoresis and then sequenced.Finally,the structure and function of TLR9 sequence were predicted by molecular biological software.[Result] The complete sequence of TLR9 gene was 3 192 bp in length,encoding 1 064 amino acids with a signal peptide composed of 30 amino acids;the leucine percentage reached as high as 18.5%.The TLR9 amino acid possibly contained three hydrophobic regions,at amino acids 455-475,740-760 and 780-800.The 3-D structure of TLR9 was constructed by the extracellular LRR domain and intracellular TIL domain(Toll/IL IR).[Conclusion] The characteristics of TLR9 provided theoretical basis for further study on the TLR9 gene of wild Ovis ammon in Xinjiang.展开更多
[Objective] cDNA of growth hormone releasing hormone (GHRH) receptor gene from Wuzhishan miniature pig was cloned and its sequence was also analyzed. [Method] Using genomic DNA extracted from porcine ear tissues of ...[Objective] cDNA of growth hormone releasing hormone (GHRH) receptor gene from Wuzhishan miniature pig was cloned and its sequence was also analyzed. [Method] Using genomic DNA extracted from porcine ear tissues of Wuzhishan miniature pig as the template, three pairs of primers were designed by the reported cDNA sequence of porcine GHRH, and cDNA was also amplified by RT-PCR. After being recovered and purified, PCR products were ligated to pMD18-T and then transformed into Escherichia coli DH5a. The transformation products were analyzed by PCR and double enzyme digestion to screen positive clones, and the positive clones were sequenced after identification in LB liquid medium. [ Result] cDNA of Wuzhishan miniature pig GHRH receptor gene was obtained successfully, and its length was 1 577 bp coding 423 amino acids. BLAST analysis showed that there were only 23 nuoleotides in difference between this fragment and pomine GHRH receptor gene, and its homology was 98%. However, both GHRH receptor genes were constituted by 423 amino acids with the sequence homology of 96%. [ Conclusion] This study provides theoretical basis for further studies on the dwarf mechanism of Wuzhishan miniature pig.展开更多
Although a growing number of both sequence-based and microsatellite nuclear loci have been used to infer genetic structures, their relative efficiencies remain poorly understood. In our study, we used the Green-backed...Although a growing number of both sequence-based and microsatellite nuclear loci have been used to infer genetic structures, their relative efficiencies remain poorly understood. In our study, we used the Green-backed Tit (Parus monticolus) to explore the resolving ability of these two types of markers. The south-western and central mitochondrial DNA (mtDNA) phylogroups were divergent to some extent in sequence-based nuclear data, while mixed together in microsatellites data. The F ST values among clades were about four times lower in microsatellite loci than those in sequence-based nuclear loci. We are of the opinion that size homoplasy may have contributed to the inability of microsatellites to uncover differentiation. Our results suggest that sequence-based nuclear loci outperformed microsatellite loci in detecting population structures, especially those focused on populations with large effective population sizes. There was no significant correlation between F ST values and allelic size variability, which suggested that the efficiency of microsatellite loci in detecting genetic structure may be independent of their polymorphism. F ST is better than R ST in detecting intraspecific divergence due to the high variance of R ST . In agreement with sequence-based nuclear loci, microsatellite loci did resolve the genetic distinctness of the Taiwan Residents phylogroup. The genetic differentiation between the Taiwan Residents and continental clades may involve allopatric divergence without gene flow.展开更多
A series of alditol derivatives were designed and synthesized with relatively high yield. On the basis of reaction between sorbitol and a series of substituted benzaldehyde in the presence of an acid catalyst, a serie...A series of alditol derivatives were designed and synthesized with relatively high yield. On the basis of reaction between sorbitol and a series of substituted benzaldehyde in the presence of an acid catalyst, a series of acetal derivatives were synthesized through free hydroxyl esterification. D-sorbitol acetal amido derivatives were prepared by reduction of nitryl and acylation of amino. D-sorbitol acetal carboxyl esterification derivatives were prepared through esterification and hydrolysis. By high performance liquid chromatography-mass spectra (HPLC-MS) and 1H nuclear magnetic resonance spectra (1H-NMR), 36 compounds prepared were identified. Among these derivatives prepared, 26 compounds have not been reported in the previous literatures.展开更多
Events Calendar 2009 January 12-15, 2009 Hyatt Regency San Francisco, San Francisco, CA Mouse Models of Cancer January 21-24, 2009 Westin San Diego Hotel, San Diego, CA Advances in Prostate Cancer Research
Events Calendar 2009January 12-15, 2009 Hyatt Regency San Francisco, San Francisco, CA Mouse Models of Cancer January 21-24, 2009 Westin San Diego Hotel San Diego, CA Advances in Prostate Cancer Research
Seismic stratigraphic analysis of 150 km of high resolution seismic profiles (GEOPULSE and 3.5 kHz) obtained along the muddy coast off Taishan, Guangdong provided valuable information on the offshore Quaternary strati...Seismic stratigraphic analysis of 150 km of high resolution seismic profiles (GEOPULSE and 3.5 kHz) obtained along the muddy coast off Taishan, Guangdong provided valuable information on the offshore Quaternary stratigraphy, tectonics, sedimentary evolution, and environmental and engineering geology of this area.The following late Quaternary stratigraphic sequences were mapped. (1) Pleistocene alluvial silty sand and shallow marine clay; (2) coarse fluvial channel sand; (3) nearshore and bay clayey sediments. The incision of fluvial channels occurred in two stages: during the Late Pleistocene and at the beginning of the Holocene. The Pleistocene fluvial channels have been filled by coarse sand overlain by more than 10 m of late Pleistocene clay and 20-30 m of Holocene clay.The coastal area is dissected by two major fault systems: the first group strikes ENE-WSW and controls the evolution of the adjacent Quaternary basin, while the second one trends NNE-SSW. These fault systems must be taken into account in any coastal engineering considerations. In addition, both granitic and metamorphic basements were recognized.展开更多
Longmen Mountain located at the boundary between the Sichuan Basin and Tibetan Plateau,representing the steepest gradient of any edges of the plateau.Three endmember models of uplift process and mechanism have been pr...Longmen Mountain located at the boundary between the Sichuan Basin and Tibetan Plateau,representing the steepest gradient of any edges of the plateau.Three endmember models of uplift process and mechanism have been proposed,including crustal thickening,crustal flow,and crustal isostatic rebound.Here we use coeval sedimentary sequences in the foreland basin to restraint uplift process and mechanism in the Longmen Mountain.The more than 10,000 m thick Late TriassicQuaternary strata filled in this foreland basin and can be divided into six megasequences that are distinguished as two distinct types.The first type is the wedge-shaped megasequences which are sedimentary response of strong active thrust loading events,characterized by a high rate of subsidence and sediment accumulation,coarsening-upward succession and a dual-sourced sediment supply.This type includes Late Triassic,Late Jurassic to Early Cretaceous and Late Cretaceous to Paleogene megasequences.The second type is the tabular megasequences,characterized by the low rate of subsidence and sediment accumulation,finingupward succession,and a single-sourced sediment supply,which is sedimentary response of isostatic rebound and erosion unloading.This type includes the Early to Middle Jurassic,Middle Cretaceous and Neogene to Quaternary megasequences.Basing on sedimentary,active tectonic,geomorphic evidence,we infer that the direction has been reversed from SSWdirected sinistral strike-slip to NNE-directed dextral strike-slip during 40-3.6 Ma,and since 3.6 Ma,the Longmen Mountain thrust belt belong to times of isostatic rebound and erosional unloading with NNEdirected dextral strike-slip.This suggests that crustal isostatic rebound is a primary driver for uplift and topography of the present Longmen Mountain.The Wenchuan(Ms8.0) earthquake,which ruptured a large thrust fault with NNE-directed dextral strikeslip along the range front,is an active manifestation of this crustal isostatic rebound process with dextral strike-slipping and shortening.This process may be the cause for the Wenchuan Earthquake and the apparent paradox of high relief,little shortening,the relative dearth of historical seismicity in the region.展开更多
One bioleaching bacterium, named as strain DXS, was isolated from acid mine drainages (AMDs) of Dongxiangshan Mine of Hami, Xinjiang Province, China. The strain DXS is gram-negative and rod-shaped with a size of (0...One bioleaching bacterium, named as strain DXS, was isolated from acid mine drainages (AMDs) of Dongxiangshan Mine of Hami, Xinjiang Province, China. The strain DXS is gram-negative and rod-shaped with a size of (0.40±0.05) μm x (1.3±0.5) μm. The optimal temperature and pH for growth are 30 ℃ and pH 2.0, respectively. It can grow autotrophically by using ferrous iron, elemental sulfur and NaS203 as sole energy sources. In the phylogenetic tree, strain DXS has similarity with Acidithiobacillus ferrooxidans type strain ATCC 23270 with 99.57% sequence similarity. The cloning and sequencing of Iro protein gene (iro) and tetrathionate hydrolase gene (tth) reveal that strain DXS is completely identical in iro gene sequence to A. ferrooxidans LY (DQ166841), and almost identical in tth gene sequene to .4. ferrooxidans (AB259312) (only two nucleotides change). The bioleaching experiments of marmatite and pyrite reveal that the leached zinc and iron concentrations reach 3.01 g/L and 2.75 g/L, respectively. The strain has a well potential application in industry bioleaching.展开更多
Yingcheng Formation is a set of volcanic strata composed of lava rocks,volcanic clastic rocks and sedimentary rocks,filled in some fault depressions in Songliao Basin,early Cretaceous.The study about litho-facies succ...Yingcheng Formation is a set of volcanic strata composed of lava rocks,volcanic clastic rocks and sedimentary rocks,filled in some fault depressions in Songliao Basin,early Cretaceous.The study about litho-facies succession of Yingcheng Formation in the outcropped area of the southeast margin and in Xujiaweizi fault depression and its distribution based on analysis of seismic data,shows that the sequence of volcanic strata is quite different from the clastic sedimentary sequence.To study the architecture of volcanic sequence and its structural control of Yingcheng Formation in Songliao Basin,in this work,dividing of the volcanic sequence and dating of the sequence boundaries were finished firstly,then displacement and displacement rate of faults were calculated.The results show that,sample ages of top of the first member,the seconde member,and the third member are 127 Ma,115 Ma,110.7 Ma,respectively and sample age of the bottom of the third member is 114.7 Ma.The maximum displacement and displacement rate of the fault 1 are 3 km and 300 m/Ma,respectively,and those of the fault 2 are 3 km and 1000 m/Ma.Studies suggest that,the cooling unit of lava rock or pyroclastic rock is a basic genetic stratigraphic unit in volcanic sequence stratigraphy.Cooling units can construct a parasequence reflecting a volcanic eruption stage.A sequence was superimposed by some parasequences,responding to a volcanic active cycle.There are three types of volcanic sequences in Yingcheng Formation: type of explosion,type of effusion and type of mixed explosion-effusion.The surface of the volcanic sequence,an unconformity surface widely spread and traced in seismic profiles,is a base for analysis of volcanic sequence.The development of volcanic sequence was controlled by faulting,and the curves of fault displacement(rate)can reflect this control.The preservation of volcanic sequence was controlled by the type of volcanic structure and the regional subsidence,also different from that of the sedimentary.The type of volcanic structure of Xujiaweizi was a volcanic depression during the forming of Yingcheng Formation,and the breakdowns of volcanoes and structural subsidence were key factors in the volcanic sequences preservation.展开更多
基金Supported by Natural Science Foundation of Jiangsu Province(BK2007561)~~
文摘[Objective] The aim of this study was to reveal the relationship between inihibin (INH) α precursor gene and seasonal reproduction of goats, and investigate the evolutionary conservation of INHα precursor gene. [ Method] Cloning and sequence analysis of 5' flanking region and exon of inihibinα (INHE) precursor gene in twenty ewes between non-seasonal estrous breed (Haimen goats) and seasonal estrous breed (Anhui white goats) was analyzed in this study. [ Result] Compared with Anhui white goats, INHα precursor gene in Haimen goats had three SNP but no amino acid change, while its nucleotide homology was 99.7% and amino acid homology was 100%. The nucleotide homology of INHα precursor gene in goat, cattle, pig, person, chicken, horse, rat and dog ranged from 12.7% to 96.5%. [ Conclusion] INHα precursor gene tends to be highly conserved in species, and any change of nucleotide and amino acid maybe directly influence the function of the whole gene coding and regulation.
文摘[Objective] The study aimed at cloning and identifying the toll receptor gene 9(TLR9) of wild Ovis ammon in Xinjiang,and predicting its structure and function.[Method] The TLR9 complete sequence of wild Ovis ammon was cloned from its peripheral blood by PCR technology.Then the PCR products were purified by agarose gel electrophoresis and then sequenced.Finally,the structure and function of TLR9 sequence were predicted by molecular biological software.[Result] The complete sequence of TLR9 gene was 3 192 bp in length,encoding 1 064 amino acids with a signal peptide composed of 30 amino acids;the leucine percentage reached as high as 18.5%.The TLR9 amino acid possibly contained three hydrophobic regions,at amino acids 455-475,740-760 and 780-800.The 3-D structure of TLR9 was constructed by the extracellular LRR domain and intracellular TIL domain(Toll/IL IR).[Conclusion] The characteristics of TLR9 provided theoretical basis for further study on the TLR9 gene of wild Ovis ammon in Xinjiang.
基金Supported by Natural Science Foundation of Hainan Province(30515)~~
文摘[Objective] cDNA of growth hormone releasing hormone (GHRH) receptor gene from Wuzhishan miniature pig was cloned and its sequence was also analyzed. [Method] Using genomic DNA extracted from porcine ear tissues of Wuzhishan miniature pig as the template, three pairs of primers were designed by the reported cDNA sequence of porcine GHRH, and cDNA was also amplified by RT-PCR. After being recovered and purified, PCR products were ligated to pMD18-T and then transformed into Escherichia coli DH5a. The transformation products were analyzed by PCR and double enzyme digestion to screen positive clones, and the positive clones were sequenced after identification in LB liquid medium. [ Result] cDNA of Wuzhishan miniature pig GHRH receptor gene was obtained successfully, and its length was 1 577 bp coding 423 amino acids. BLAST analysis showed that there were only 23 nuoleotides in difference between this fragment and pomine GHRH receptor gene, and its homology was 98%. However, both GHRH receptor genes were constituted by 423 amino acids with the sequence homology of 96%. [ Conclusion] This study provides theoretical basis for further studies on the dwarf mechanism of Wuzhishan miniature pig.
基金supported by the National Science Fund for Distinguished Young Scientists (No. 30925008)the Major International (Regional) Joint Research Project (No. 31010103901)+1 种基金the CAS-IOZ Innovation Program (KSCX2-EW-J-2) by a grant (No. O529YX5105) from the Key Laboratory of the Zoological Systematics and Evolution of the Chinese Academy of Sciences to F.M. Lei
文摘Although a growing number of both sequence-based and microsatellite nuclear loci have been used to infer genetic structures, their relative efficiencies remain poorly understood. In our study, we used the Green-backed Tit (Parus monticolus) to explore the resolving ability of these two types of markers. The south-western and central mitochondrial DNA (mtDNA) phylogroups were divergent to some extent in sequence-based nuclear data, while mixed together in microsatellites data. The F ST values among clades were about four times lower in microsatellite loci than those in sequence-based nuclear loci. We are of the opinion that size homoplasy may have contributed to the inability of microsatellites to uncover differentiation. Our results suggest that sequence-based nuclear loci outperformed microsatellite loci in detecting population structures, especially those focused on populations with large effective population sizes. There was no significant correlation between F ST values and allelic size variability, which suggested that the efficiency of microsatellite loci in detecting genetic structure may be independent of their polymorphism. F ST is better than R ST in detecting intraspecific divergence due to the high variance of R ST . In agreement with sequence-based nuclear loci, microsatellite loci did resolve the genetic distinctness of the Taiwan Residents phylogroup. The genetic differentiation between the Taiwan Residents and continental clades may involve allopatric divergence without gene flow.
基金National Natural Science Foundation of China (No 20306022)
文摘A series of alditol derivatives were designed and synthesized with relatively high yield. On the basis of reaction between sorbitol and a series of substituted benzaldehyde in the presence of an acid catalyst, a series of acetal derivatives were synthesized through free hydroxyl esterification. D-sorbitol acetal amido derivatives were prepared by reduction of nitryl and acylation of amino. D-sorbitol acetal carboxyl esterification derivatives were prepared through esterification and hydrolysis. By high performance liquid chromatography-mass spectra (HPLC-MS) and 1H nuclear magnetic resonance spectra (1H-NMR), 36 compounds prepared were identified. Among these derivatives prepared, 26 compounds have not been reported in the previous literatures.
文摘Events Calendar 2009 January 12-15, 2009 Hyatt Regency San Francisco, San Francisco, CA Mouse Models of Cancer January 21-24, 2009 Westin San Diego Hotel, San Diego, CA Advances in Prostate Cancer Research
文摘Events Calendar 2009January 12-15, 2009 Hyatt Regency San Francisco, San Francisco, CA Mouse Models of Cancer January 21-24, 2009 Westin San Diego Hotel San Diego, CA Advances in Prostate Cancer Research
文摘Seismic stratigraphic analysis of 150 km of high resolution seismic profiles (GEOPULSE and 3.5 kHz) obtained along the muddy coast off Taishan, Guangdong provided valuable information on the offshore Quaternary stratigraphy, tectonics, sedimentary evolution, and environmental and engineering geology of this area.The following late Quaternary stratigraphic sequences were mapped. (1) Pleistocene alluvial silty sand and shallow marine clay; (2) coarse fluvial channel sand; (3) nearshore and bay clayey sediments. The incision of fluvial channels occurred in two stages: during the Late Pleistocene and at the beginning of the Holocene. The Pleistocene fluvial channels have been filled by coarse sand overlain by more than 10 m of late Pleistocene clay and 20-30 m of Holocene clay.The coastal area is dissected by two major fault systems: the first group strikes ENE-WSW and controls the evolution of the adjacent Quaternary basin, while the second one trends NNE-SSW. These fault systems must be taken into account in any coastal engineering considerations. In addition, both granitic and metamorphic basements were recognized.
基金supported by the China National Natural Science Foundation (Grant No. 40841010,40972083,41172162)CGS Foundation (Grant No.1212011121268)Foundation from State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation (Grant No. SK-0801)
文摘Longmen Mountain located at the boundary between the Sichuan Basin and Tibetan Plateau,representing the steepest gradient of any edges of the plateau.Three endmember models of uplift process and mechanism have been proposed,including crustal thickening,crustal flow,and crustal isostatic rebound.Here we use coeval sedimentary sequences in the foreland basin to restraint uplift process and mechanism in the Longmen Mountain.The more than 10,000 m thick Late TriassicQuaternary strata filled in this foreland basin and can be divided into six megasequences that are distinguished as two distinct types.The first type is the wedge-shaped megasequences which are sedimentary response of strong active thrust loading events,characterized by a high rate of subsidence and sediment accumulation,coarsening-upward succession and a dual-sourced sediment supply.This type includes Late Triassic,Late Jurassic to Early Cretaceous and Late Cretaceous to Paleogene megasequences.The second type is the tabular megasequences,characterized by the low rate of subsidence and sediment accumulation,finingupward succession,and a single-sourced sediment supply,which is sedimentary response of isostatic rebound and erosion unloading.This type includes the Early to Middle Jurassic,Middle Cretaceous and Neogene to Quaternary megasequences.Basing on sedimentary,active tectonic,geomorphic evidence,we infer that the direction has been reversed from SSWdirected sinistral strike-slip to NNE-directed dextral strike-slip during 40-3.6 Ma,and since 3.6 Ma,the Longmen Mountain thrust belt belong to times of isostatic rebound and erosional unloading with NNEdirected dextral strike-slip.This suggests that crustal isostatic rebound is a primary driver for uplift and topography of the present Longmen Mountain.The Wenchuan(Ms8.0) earthquake,which ruptured a large thrust fault with NNE-directed dextral strikeslip along the range front,is an active manifestation of this crustal isostatic rebound process with dextral strike-slipping and shortening.This process may be the cause for the Wenchuan Earthquake and the apparent paradox of high relief,little shortening,the relative dearth of historical seismicity in the region.
基金Projects(50974140, 50674101) supported by the National Natural Science Foundation of ChinaProject(2010CB630902) supported by the National Basic Research Program of China
文摘One bioleaching bacterium, named as strain DXS, was isolated from acid mine drainages (AMDs) of Dongxiangshan Mine of Hami, Xinjiang Province, China. The strain DXS is gram-negative and rod-shaped with a size of (0.40±0.05) μm x (1.3±0.5) μm. The optimal temperature and pH for growth are 30 ℃ and pH 2.0, respectively. It can grow autotrophically by using ferrous iron, elemental sulfur and NaS203 as sole energy sources. In the phylogenetic tree, strain DXS has similarity with Acidithiobacillus ferrooxidans type strain ATCC 23270 with 99.57% sequence similarity. The cloning and sequencing of Iro protein gene (iro) and tetrathionate hydrolase gene (tth) reveal that strain DXS is completely identical in iro gene sequence to A. ferrooxidans LY (DQ166841), and almost identical in tth gene sequene to .4. ferrooxidans (AB259312) (only two nucleotides change). The bioleaching experiments of marmatite and pyrite reveal that the leached zinc and iron concentrations reach 3.01 g/L and 2.75 g/L, respectively. The strain has a well potential application in industry bioleaching.
基金Project(40972074)supported by the National Natural Science Foundation of China
文摘Yingcheng Formation is a set of volcanic strata composed of lava rocks,volcanic clastic rocks and sedimentary rocks,filled in some fault depressions in Songliao Basin,early Cretaceous.The study about litho-facies succession of Yingcheng Formation in the outcropped area of the southeast margin and in Xujiaweizi fault depression and its distribution based on analysis of seismic data,shows that the sequence of volcanic strata is quite different from the clastic sedimentary sequence.To study the architecture of volcanic sequence and its structural control of Yingcheng Formation in Songliao Basin,in this work,dividing of the volcanic sequence and dating of the sequence boundaries were finished firstly,then displacement and displacement rate of faults were calculated.The results show that,sample ages of top of the first member,the seconde member,and the third member are 127 Ma,115 Ma,110.7 Ma,respectively and sample age of the bottom of the third member is 114.7 Ma.The maximum displacement and displacement rate of the fault 1 are 3 km and 300 m/Ma,respectively,and those of the fault 2 are 3 km and 1000 m/Ma.Studies suggest that,the cooling unit of lava rock or pyroclastic rock is a basic genetic stratigraphic unit in volcanic sequence stratigraphy.Cooling units can construct a parasequence reflecting a volcanic eruption stage.A sequence was superimposed by some parasequences,responding to a volcanic active cycle.There are three types of volcanic sequences in Yingcheng Formation: type of explosion,type of effusion and type of mixed explosion-effusion.The surface of the volcanic sequence,an unconformity surface widely spread and traced in seismic profiles,is a base for analysis of volcanic sequence.The development of volcanic sequence was controlled by faulting,and the curves of fault displacement(rate)can reflect this control.The preservation of volcanic sequence was controlled by the type of volcanic structure and the regional subsidence,also different from that of the sedimentary.The type of volcanic structure of Xujiaweizi was a volcanic depression during the forming of Yingcheng Formation,and the breakdowns of volcanoes and structural subsidence were key factors in the volcanic sequences preservation.