Chinese shrimp （Fenneropenaeus chinensis） is an economically important aquaculture species in China. However, cytogenetic and genomic data is limited in the organism partly because the chromosomes are difficult to i...Chinese shrimp （Fenneropenaeus chinensis） is an economically important aquaculture species in China. However, cytogenetic and genomic data is limited in the organism partly because the chromosomes are difficult to isolate and analyze. In this study, fluorescence in-situ hybridization （FISH） was used to identify the chromosomes of F. chinensis. The 5S ribosomal RNA gene （rDNA） of F. chinensis was isolated, cloned and then used as a hybridization probe. The results show that the 5S rDNA was located on one pair of homologous chromosomes in F chinensis. In addition, triploid shrimp were used to evaluate the feasibility of chromosome identification using FISH and to validate the method. It was confirmed that 5S rDNA can be used as a chromosome-specific probe for chromosome identification in E chinensis. The successful application ofFISH in E chinensis shows that chromosome-specific probes can be developed and this finding will facilitate further research on the chromosomes ofpenaeid shrimps.展开更多
Meiotic recombination is a deeply conserved process within eukaryotes that has a profound effect on patterns of natural genetic variation. During meiosis homologous chromosomes pair and undergo DNA double strand break...Meiotic recombination is a deeply conserved process within eukaryotes that has a profound effect on patterns of natural genetic variation. During meiosis homologous chromosomes pair and undergo DNA double strand breaks generated by the Spo11 endonuclease. These breaks can be repaired as crossovers that result in reciprocal exchange between chromosomes. The frequency of recombination along chromosomes is highly variable, for example, crossovers are rarely observed in heterochromatin and the centromeric regions. Recent work in plants has shown that crossover hotspots occur in gene promoters and are associated with specific chromatin modifications, including H2 A.Z. Meiotic chromosomes are also organized in loop-base arrays connected to an underlying chromosome axis, which likely interacts with chromatin to organize patterns of recombination.Therefore, epigenetic information exerts a major influence on patterns of meiotic recombination along chromosomes, genetic variation within populations and evolution of plant genomes.展开更多
The combined lines having both phKL and Ph2-deficiency were obtained in the genetic background of common wheat (Triticum aestivum L.) landrace. These lines had normal fertility. In the wheat combined lines X Aegilops ...The combined lines having both phKL and Ph2-deficiency were obtained in the genetic background of common wheat (Triticum aestivum L.) landrace. These lines had normal fertility. In the wheat combined lines X Aegilops variabilis Eig. (or rye), a significant increase in the chiasmata of homoeologous pairing was shown by the phKL+Ph2(-) plants with respect to their phKL+Ph2 sibs, which indicates that Ph2-deficiency and phKL showed an additive effect on promoting pairing. The effects were shown in the increment of rod bivalents, ring bivalents and trivalents and reduction of univalents, of which, reduction of univalents was mainly due to the increment of rod bivalents. The combined lines are probably more desirable materials for alien gene transferring than phKL or Ph2(-) lines alone. In comparison with that of ph1b X Ae. variabilis (or rye), phKL+Ph2(-) X Ae. variabilis (or rye) show higher (or similar) numbers of rod bivalents, while the total chromosome pairing level significantly reduced that ascribed to the decrement in ring bivalents and multivalents. These results probably indicate the different genetic mechanisms for Ph1 and Ph2 or phKL on controlling homoeologous pairing.展开更多
Meiosis comprises two rounds of nuclear division following a single phase of DNA replication, leading to the production of haploid gametes and is essential for sexual reproduction in eukaryotes. Unlike mitosis, meiosi...Meiosis comprises two rounds of nuclear division following a single phase of DNA replication, leading to the production of haploid gametes and is essential for sexual reproduction in eukaryotes. Unlike mitosis, meiosis involves homologous chromosome pairing, synapsis, and recombination during prophase I. Meiotic recombination not only ensures the accurate segregation of homologs, but also redistributes alleles among offspring. DNA synthesis is a critical process during meiotic recombination, but our understanding of the proteins that execute and regulate it is limited. This review summarizes the recent advances in defining the role of DNA synthesis in meiotic recombina- tion through analyses of DNA synthesis genes, with specific emphasis on DNA polymerases （e.g., Pole and PolS）, replication processivity factor RFC1 and translesion polymerases （e.g., Pol~）. We also present a new double strand break repair model for meiotic recombination, which includes lagging strand DNA synthesis and leading strand elongation. Finally, we propose that DNA synthesis is one of critical factors for discriminating meiotic recombination pathways and that this differentiation may be conserved among eukaryotes.展开更多
W952684 杂种小麦:现代杂种的表现和生产[会,英]/Wilson,P.//Wheat Breeding-into the secondcentury.Proceedings of The Seventh AssemblyWheat Breeding Society of Australia,The Universityof Adelaide,25～30 Sep.1994/Paull,J.…...W952684 杂种小麦:现代杂种的表现和生产[会,英]/Wilson,P.//Wheat Breeding-into the secondcentury.Proceedings of The Seventh AssemblyWheat Breeding Society of Australia,The Universityof Adelaide,25～30 Sep.1994/Paull,J.….-Ade-laide,Australia:Wheat Breeding Society of Australi-a,1994.展开更多
基金Supported by the Key Program of the National Natural ScienceFoundation of China(No.30730071)the National High-Tech Researchand Development Program of China(863 program)(No.2007AA09Z430)the General Program of National Natural Science Foundation of China(Nos.30471347&40706048)
文摘Chinese shrimp （Fenneropenaeus chinensis） is an economically important aquaculture species in China. However, cytogenetic and genomic data is limited in the organism partly because the chromosomes are difficult to isolate and analyze. In this study, fluorescence in-situ hybridization （FISH） was used to identify the chromosomes of F. chinensis. The 5S ribosomal RNA gene （rDNA） of F. chinensis was isolated, cloned and then used as a hybridization probe. The results show that the 5S rDNA was located on one pair of homologous chromosomes in F chinensis. In addition, triploid shrimp were used to evaluate the feasibility of chromosome identification using FISH and to validate the method. It was confirmed that 5S rDNA can be used as a chromosome-specific probe for chromosome identification in E chinensis. The successful application ofFISH in E chinensis shows that chromosome-specific probes can be developed and this finding will facilitate further research on the chromosomes ofpenaeid shrimps.
文摘Meiotic recombination is a deeply conserved process within eukaryotes that has a profound effect on patterns of natural genetic variation. During meiosis homologous chromosomes pair and undergo DNA double strand breaks generated by the Spo11 endonuclease. These breaks can be repaired as crossovers that result in reciprocal exchange between chromosomes. The frequency of recombination along chromosomes is highly variable, for example, crossovers are rarely observed in heterochromatin and the centromeric regions. Recent work in plants has shown that crossover hotspots occur in gene promoters and are associated with specific chromatin modifications, including H2 A.Z. Meiotic chromosomes are also organized in loop-base arrays connected to an underlying chromosome axis, which likely interacts with chromatin to organize patterns of recombination.Therefore, epigenetic information exerts a major influence on patterns of meiotic recombination along chromosomes, genetic variation within populations and evolution of plant genomes.
文摘The combined lines having both phKL and Ph2-deficiency were obtained in the genetic background of common wheat (Triticum aestivum L.) landrace. These lines had normal fertility. In the wheat combined lines X Aegilops variabilis Eig. (or rye), a significant increase in the chiasmata of homoeologous pairing was shown by the phKL+Ph2(-) plants with respect to their phKL+Ph2 sibs, which indicates that Ph2-deficiency and phKL showed an additive effect on promoting pairing. The effects were shown in the increment of rod bivalents, ring bivalents and trivalents and reduction of univalents, of which, reduction of univalents was mainly due to the increment of rod bivalents. The combined lines are probably more desirable materials for alien gene transferring than phKL or Ph2(-) lines alone. In comparison with that of ph1b X Ae. variabilis (or rye), phKL+Ph2(-) X Ae. variabilis (or rye) show higher (or similar) numbers of rod bivalents, while the total chromosome pairing level significantly reduced that ascribed to the decrement in ring bivalents and multivalents. These results probably indicate the different genetic mechanisms for Ph1 and Ph2 or phKL on controlling homoeologous pairing.
基金Acknowledgments We apologize to colleagues whose work could not be cited owing to space constraints. J.H., H.M. and Y.W. are supported by the Ministry of Science and Technology of China （2011CB944603）, the National Natural Science Foundation of China （31370347）, and by funds from Fudan University and Rijk Zwaan. G.P.C. is supported by the US National Science Foundation （MCB- 1121563） and Rijk Zwaan.
文摘Meiosis comprises two rounds of nuclear division following a single phase of DNA replication, leading to the production of haploid gametes and is essential for sexual reproduction in eukaryotes. Unlike mitosis, meiosis involves homologous chromosome pairing, synapsis, and recombination during prophase I. Meiotic recombination not only ensures the accurate segregation of homologs, but also redistributes alleles among offspring. DNA synthesis is a critical process during meiotic recombination, but our understanding of the proteins that execute and regulate it is limited. This review summarizes the recent advances in defining the role of DNA synthesis in meiotic recombina- tion through analyses of DNA synthesis genes, with specific emphasis on DNA polymerases （e.g., Pole and PolS）, replication processivity factor RFC1 and translesion polymerases （e.g., Pol~）. We also present a new double strand break repair model for meiotic recombination, which includes lagging strand DNA synthesis and leading strand elongation. Finally, we propose that DNA synthesis is one of critical factors for discriminating meiotic recombination pathways and that this differentiation may be conserved among eukaryotes.
文摘W952684 杂种小麦:现代杂种的表现和生产[会,英]/Wilson,P.//Wheat Breeding-into the secondcentury.Proceedings of The Seventh AssemblyWheat Breeding Society of Australia,The Universityof Adelaide,25～30 Sep.1994/Paull,J.….-Ade-laide,Australia:Wheat Breeding Society of Australi-a,1994.
