The potato rot nematode(Ditylenchus destructor) is a very economically important nematode in agronomic and horticultural plants worldwide. In this study, 43 populations of D. destructor were collected from different h...The potato rot nematode(Ditylenchus destructor) is a very economically important nematode in agronomic and horticultural plants worldwide. In this study, 43 populations of D. destructor were collected from different hosts across China, including 37 populations from Chinese herbal medicine plants. Obtained sequences of ITS-rDNA and D2–D3of 28S-rDNA genes of D. destructor were compared and analyzed. Nine types of significant length variations in ITS sequences were observed among all populations. The differences in ITS1 length were mainly caused by the presence of repetitive elements with substantial base substitutions. Reconstructions of ITS1 secondary structures showed that the minisatellites formed a stem structure. Ten haplotypes were observed in all populations based on mutations and variations of helix H9. Among them, 3 known haplotypes(A–C) were found in 7 populations isolated from potato,sweet potato, and Codonopsis pilosula, and 7 unique haplotypes were found in other 36 populations collected from C. pilosula and Angelica sinensis compared with 7 haplotypes(A–G) according to Subbotin' system. These unique haplotypes were different from haplotypes A–G, and we named them as haplotypes H–N. The present results showed that a total of 14 haplotypes(A–N) of ITS-rDNA have been found in D. destructor. Phylogenetic analyses of ITSrDNA and D2–D3 showed that all populations of D. destructor were clustered into two major clades: one clade only containing haplotype A from sweet potato and the other containing haplotypes B–N from other plants. For further verification, PCR-ITS-RFLP profiles were conducted on 7 new haplotypes. Collectively, our study suggests that D. destructor populations on Chinese medicinal materials are very different from those on other hosts and this work provides a paradigm for relevant researches.展开更多
Through random sequencing, we found a total of 884000 base-pairs (bp) of random genomic sequences in the genome of Chinese shrimp (Fenneropenaeus chinensis). Using bio-soft Tandem Repeat Finder (TRF) software, 2159 ta...Through random sequencing, we found a total of 884000 base-pairs (bp) of random genomic sequences in the genome of Chinese shrimp (Fenneropenaeus chinensis). Using bio-soft Tandem Repeat Finder (TRF) software, 2159 tandem repeats were found, in which there were 1714 mi- crosatellites and 445 minisatellites, accounting for 79.4% and 20.6% of repeat sequences, respectively. The cumulative length of repeat sequences was found to be 116685 bp, ac- counting for 13.2% of the total DNA sequence; the cumula- tive length of microsatellites occupied 9.78% of the total DNA sequence, and that of minisatellites occupied 3.42%. In decreasing order, the 20 most abundant repeat sequence classes were as follows: AT (557), AC (471), AG (274), AAT (92), A (56), AAG (28), ATC (27), ATAG (27), AGG (18), ACT (15), C (11), AAC (11), ACAT (11), CAGA (10), AGAA (9), AGGG (7), CAAA (7), CGCA (6), ATAA (6), AGAGAA (6). Dinucleotide repeats, not only in the aspect of the number, but also in cumulative length, were the preponderant repeat type. There were few classes and low copy numbers of repeat units of the pentanucleotide repeat type, which included only three classes: AGAGA, GAGGC and AAAGA. The classes and copy numbers of heptanucleotide, eleven-nucleotide and thirteen-nucleotide primer-number-composed repeats were distinctly less than that of repeat types beside them.展开更多
In this paper,the fault-tolesant attitude aynchronisation aontrol problem for a team of bet-soganua man leatellita in addrsed,subject to multaple actuator faulta and uneertainties in the satellite dynamles.A fully dis...In this paper,the fault-tolesant attitude aynchronisation aontrol problem for a team of bet-soganua man leatellita in addrsed,subject to multaple actuator faulta and uneertainties in the satellite dynamles.A fully distributed adapSe fault-tokerant controlker,completely inde pendently of the knowledge of the gobal infarmation,is propoaed to achieve the desired attstude aynchranlatin.The attitade tracking aror of the glohal clased-loop eantrol aystem is paoven to onverge into a givan naighborbood of the origin ultimately.Simmlation rasults are givan to validate the afectivenas and advantaga of the propased adaptive controller dor the belerogenaou satellite formation flying team,against the infuenoe of actuator faults and umeertaintin.展开更多
The level of genetic variation among individuals may affect performance by reducing the ability of prey to detect and escape from predators if lack of genetic variation reduces flight ability directly or indirectly th...The level of genetic variation among individuals may affect performance by reducing the ability of prey to detect and escape from predators if lack of genetic variation reduces flight ability directly or indirectly through reduced parasite resistance. We investigated vulnerability of common avian prey species to predation by the sparrowhawk Accipiter nisus and the goshawk A. gentilis in relation to an index of genetic similarity among adults of potential prey species. We estimated a prey vulnerability in- dex that reflects the abundance of prey relative to the expected abundance according to local population density, and related this index to band sharing coefficients based on analyses of minisatellites for adults in local breeding populations. The prey vulnera- bility index was positively correlated with the band sharing coefficient in both predators, even when controlling for potentially confounding variables. These findings indicate that prey species with high band sharing coefficients, and hence low levels of genetic variation, are more readily caught by avian predators. Therefore, predation may constitute a major cost of low levels of genetic variation in extant populations of prey [Current Zoology 61（1）： 1-9, 2015].展开更多
Firstly, the Earth＇s gravitational field from the past Challenging Minisatellite Payload （CHAMP） mission is determined using the energy conservation principle, the combined error model of the cumulative geoid heigh...Firstly, the Earth＇s gravitational field from the past Challenging Minisatellite Payload （CHAMP） mission is determined using the energy conservation principle, the combined error model of the cumulative geoid height influenced by three instrument errors from the current Gravity Recovery and Climate Experiment （GRACE） and future GRACE Follow-On missions is established based on the semi-analytical method, and the Earth＇s gravitational field from the executed Gravity Field and Steady-State Ocean Circulation Explorer （GOCE） mission is recovered by the space-time-wise approach. Secondly, the cumulative geoid height errors are 1.727 × 10^-1 m, 1.839 × 10^-1 m and 9.025 × 10^ -2 m at degrees 70,120 and 250 from the implemented three-stage satellite gravity missions consisting of CHAMP, GRACE and GOCE, which preferably accord with those from the existing earth gravity field models involving EIGEN-CHAMP03S, EICEN-GRACE02S and GO_CONS GCF 2 DIR R1. The cumulative geoid height error is 6.847 × 10 ^-2 m at degree 250 from the future GRACE Follow-On mission. Finally, the complementarity among the four-stage satellite gravity missions including CHAMP, GRACE, GOCE and GRACE Follow-On is demonstrated contrastively.展开更多
Centromeres play a vital role in cellular division by facilitating kinetochore assembly and spindle attachments.Despite their conserved functionality,centromeric DNA sequences exhibit rapid evolution,presenting divers...Centromeres play a vital role in cellular division by facilitating kinetochore assembly and spindle attachments.Despite their conserved functionality,centromeric DNA sequences exhibit rapid evolution,presenting diverse sizes and compositions across species.The functional significance of rye centromeric DNA sequences,particularly in centromere identity,remains unclear.In this study,we comprehensively characterized the sequence composition and organization of rye centromeres.Our findings revealed that these centromeres are primarily composed of long terminal repeat retrotransposons(LTR-RTs)and interspersed minisatellites.We systematically classified LTR-RTs into five categories,highlighting the prevalence of younger CRS1,CRS2,and CRS3 of CRSs(centromeric retrotransposons of Secale cereale)were primarily located in the core centromeres and exhibited a higher association with CENH3 nucleosomes.The minisatellites,mainly derived from retrotransposons,along with CRSs,played a pivotal role in establishing functional centromeres in rye.Additionally,we observed the formation of R-loops at specific regions of CRS1,CRS2,and CRS3,with both rye pericentromeres and centromeres exhibiting enrichment in R-loops.Notably,these R-loops selectively formed at binding regions of the CENH3 nucleosome in rye centromeres,suggesting a potential role in mediating the precise loading of CENH3 to centromeres and contributing to centromere specification.Our work provides insights into the DNA sequence composition,distribution,and potential function of R-loops in rye centromeres.This knowledge contributes valuable information to understanding the genetics and epigenetics of rye centromeres,offering implications for the development of synthetic centromeres in future plant modifications and beyond.展开更多
基金supported by the National Natural Science Foundation of China (31760507)the National Key R&D Program of China (2018YFC1706301)。
文摘The potato rot nematode(Ditylenchus destructor) is a very economically important nematode in agronomic and horticultural plants worldwide. In this study, 43 populations of D. destructor were collected from different hosts across China, including 37 populations from Chinese herbal medicine plants. Obtained sequences of ITS-rDNA and D2–D3of 28S-rDNA genes of D. destructor were compared and analyzed. Nine types of significant length variations in ITS sequences were observed among all populations. The differences in ITS1 length were mainly caused by the presence of repetitive elements with substantial base substitutions. Reconstructions of ITS1 secondary structures showed that the minisatellites formed a stem structure. Ten haplotypes were observed in all populations based on mutations and variations of helix H9. Among them, 3 known haplotypes(A–C) were found in 7 populations isolated from potato,sweet potato, and Codonopsis pilosula, and 7 unique haplotypes were found in other 36 populations collected from C. pilosula and Angelica sinensis compared with 7 haplotypes(A–G) according to Subbotin' system. These unique haplotypes were different from haplotypes A–G, and we named them as haplotypes H–N. The present results showed that a total of 14 haplotypes(A–N) of ITS-rDNA have been found in D. destructor. Phylogenetic analyses of ITSrDNA and D2–D3 showed that all populations of D. destructor were clustered into two major clades: one clade only containing haplotype A from sweet potato and the other containing haplotypes B–N from other plants. For further verification, PCR-ITS-RFLP profiles were conducted on 7 new haplotypes. Collectively, our study suggests that D. destructor populations on Chinese medicinal materials are very different from those on other hosts and this work provides a paradigm for relevant researches.
基金supported by grants from the National Basic Research Priorities Programme(973)(Grant No.G1999012007)the National High-Tech Research and Development Program of China(863)(Grant No.2003AA603021)Open-end Funds of Key Laboratory of Fisheris Genetic Resources&Aquaculture,Chinese Academy of Fisheries Sciences(South China Sea Fisheries Research Institute,Chinese Academy of Fishery Sciences)
文摘Through random sequencing, we found a total of 884000 base-pairs (bp) of random genomic sequences in the genome of Chinese shrimp (Fenneropenaeus chinensis). Using bio-soft Tandem Repeat Finder (TRF) software, 2159 tandem repeats were found, in which there were 1714 mi- crosatellites and 445 minisatellites, accounting for 79.4% and 20.6% of repeat sequences, respectively. The cumulative length of repeat sequences was found to be 116685 bp, ac- counting for 13.2% of the total DNA sequence; the cumula- tive length of microsatellites occupied 9.78% of the total DNA sequence, and that of minisatellites occupied 3.42%. In decreasing order, the 20 most abundant repeat sequence classes were as follows: AT (557), AC (471), AG (274), AAT (92), A (56), AAG (28), ATC (27), ATAG (27), AGG (18), ACT (15), C (11), AAC (11), ACAT (11), CAGA (10), AGAA (9), AGGG (7), CAAA (7), CGCA (6), ATAA (6), AGAGAA (6). Dinucleotide repeats, not only in the aspect of the number, but also in cumulative length, were the preponderant repeat type. There were few classes and low copy numbers of repeat units of the pentanucleotide repeat type, which included only three classes: AGAGA, GAGGC and AAAGA. The classes and copy numbers of heptanucleotide, eleven-nucleotide and thirteen-nucleotide primer-number-composed repeats were distinctly less than that of repeat types beside them.
基金supported by the National Natural Science Foundation of China under Grant 61873012.
文摘In this paper,the fault-tolesant attitude aynchronisation aontrol problem for a team of bet-soganua man leatellita in addrsed,subject to multaple actuator faulta and uneertainties in the satellite dynamles.A fully distributed adapSe fault-tokerant controlker,completely inde pendently of the knowledge of the gobal infarmation,is propoaed to achieve the desired attstude aynchranlatin.The attitade tracking aror of the glohal clased-loop eantrol aystem is paoven to onverge into a givan naighborbood of the origin ultimately.Simmlation rasults are givan to validate the afectivenas and advantaga of the propased adaptive controller dor the belerogenaou satellite formation flying team,against the infuenoe of actuator faults and umeertaintin.
文摘The level of genetic variation among individuals may affect performance by reducing the ability of prey to detect and escape from predators if lack of genetic variation reduces flight ability directly or indirectly through reduced parasite resistance. We investigated vulnerability of common avian prey species to predation by the sparrowhawk Accipiter nisus and the goshawk A. gentilis in relation to an index of genetic similarity among adults of potential prey species. We estimated a prey vulnerability in- dex that reflects the abundance of prey relative to the expected abundance according to local population density, and related this index to band sharing coefficients based on analyses of minisatellites for adults in local breeding populations. The prey vulnera- bility index was positively correlated with the band sharing coefficient in both predators, even when controlling for potentially confounding variables. These findings indicate that prey species with high band sharing coefficients, and hence low levels of genetic variation, are more readily caught by avian predators. Therefore, predation may constitute a major cost of low levels of genetic variation in extant populations of prey [Current Zoology 61（1）： 1-9, 2015].
基金supported by the Main Direction Program of Knowledge Innovation of Chinese Academy of Sciences for Distinguished Young Scholar(KZCX2-EW-QN114)the National Natural Science Foundation of China(41004006,41131067,11173049 and 41274041)+7 种基金the Merit-based Scientific Research Foundation of the State Ministry of Human Resources and Social Security of China for Returned Overseas Chinese Scholars(Z01101)the Open Research Fund Program of the Key Laboratory of Geospace Environment and Geodesy,Ministry of Education,China(11-01-02)the Open Research Fund Program of the Key Laboratory of Geo-Informatics of National Administration of Surveying,Mapping and Geoinformation of China(201322)the Open Research Fund Program of the State Key Laboratory of Geoinformation Engineering,China(SKLGIE2013-M-1-5)the Main Direction Program of Institute of Geodesy and Geophysics,Chinese Academy of Sciences(Y309451045)the Research Fund Program of State Key Laboratory of Geodesy and Earth's Dynamics,China(Y309491050)the Research Fund of the National Civilian Space Infrastructure Project(Y419341034)the Research Fund of the Lu Jiaxi Young Talent and the Youth Innovation Promotion Association of Chinese Academy of Science(Y305171017)
文摘Firstly, the Earth＇s gravitational field from the past Challenging Minisatellite Payload （CHAMP） mission is determined using the energy conservation principle, the combined error model of the cumulative geoid height influenced by three instrument errors from the current Gravity Recovery and Climate Experiment （GRACE） and future GRACE Follow-On missions is established based on the semi-analytical method, and the Earth＇s gravitational field from the executed Gravity Field and Steady-State Ocean Circulation Explorer （GOCE） mission is recovered by the space-time-wise approach. Secondly, the cumulative geoid height errors are 1.727 × 10^-1 m, 1.839 × 10^-1 m and 9.025 × 10^ -2 m at degrees 70,120 and 250 from the implemented three-stage satellite gravity missions consisting of CHAMP, GRACE and GOCE, which preferably accord with those from the existing earth gravity field models involving EIGEN-CHAMP03S, EICEN-GRACE02S and GO_CONS GCF 2 DIR R1. The cumulative geoid height error is 6.847 × 10 ^-2 m at degree 250 from the future GRACE Follow-On mission. Finally, the complementarity among the four-stage satellite gravity missions including CHAMP, GRACE, GOCE and GRACE Follow-On is demonstrated contrastively.
基金supported by the National Natural Science Foundation of China(31991212,31920103006)。
文摘Centromeres play a vital role in cellular division by facilitating kinetochore assembly and spindle attachments.Despite their conserved functionality,centromeric DNA sequences exhibit rapid evolution,presenting diverse sizes and compositions across species.The functional significance of rye centromeric DNA sequences,particularly in centromere identity,remains unclear.In this study,we comprehensively characterized the sequence composition and organization of rye centromeres.Our findings revealed that these centromeres are primarily composed of long terminal repeat retrotransposons(LTR-RTs)and interspersed minisatellites.We systematically classified LTR-RTs into five categories,highlighting the prevalence of younger CRS1,CRS2,and CRS3 of CRSs(centromeric retrotransposons of Secale cereale)were primarily located in the core centromeres and exhibited a higher association with CENH3 nucleosomes.The minisatellites,mainly derived from retrotransposons,along with CRSs,played a pivotal role in establishing functional centromeres in rye.Additionally,we observed the formation of R-loops at specific regions of CRS1,CRS2,and CRS3,with both rye pericentromeres and centromeres exhibiting enrichment in R-loops.Notably,these R-loops selectively formed at binding regions of the CENH3 nucleosome in rye centromeres,suggesting a potential role in mediating the precise loading of CENH3 to centromeres and contributing to centromere specification.Our work provides insights into the DNA sequence composition,distribution,and potential function of R-loops in rye centromeres.This knowledge contributes valuable information to understanding the genetics and epigenetics of rye centromeres,offering implications for the development of synthetic centromeres in future plant modifications and beyond.
