[ Objective] This study aimed to conduct the karyotype analysis of Rabdosia lophanthoides var. gerardians and R. lophanthoides Hara var. gracilifloruschromosomes. [ Method] Vigorously growing shoot tips of R. lophanth...[ Objective] This study aimed to conduct the karyotype analysis of Rabdosia lophanthoides var. gerardians and R. lophanthoides Hara var. gracilifloruschromosomes. [ Method] Vigorously growing shoot tips of R. lophanthoides var. gerardianus and R. lophanthoides Hara var. graciliflorus were stained for section preparation to observe and analyze the chromosomes. [ Result] Karyotype formula of R. lophanthoides var. gerardianus is K （2n） =2x =24 = 18m ＋4Sm, sugges- ting that this species belongs to category 2A of Stebbins; karyotype formula of R. lophanthoides Hara var. graciliflorus is K （2n） =2x =24 = 16m ＋8Sm, sugges- ting that this species belongs to category 1B of Stebbins. [Conclusion] R. lophanthoides var. gerardianus is more primitive compared with R. lophanthoides Hara var. graciliflorus.展开更多
Objeclive The aim of this study was to investigate R-band of Cervus nippon hortulorum chromosomes and to provide references for genetic variation and gene location of Cervus nippon hortulorum. [Metbod] Cell division w...Objeclive The aim of this study was to investigate R-band of Cervus nippon hortulorum chromosomes and to provide references for genetic variation and gene location of Cervus nippon hortulorum. [Metbod] Cell division was synchronized by the pepripheral blood lymphocyte culture and the excessive dosage of thymine deoxyribonucleoside, and R-band of Cervus nippon hortulorum chromosomes was also analyzed by RBG-banding technique. Result The number of haploid chromosome banding increased to 400. The R-band of No. 1, No. 2, No. 3, No. 4, chromosome X and Y were almost just opposite to the high-resolution G band of them. The terminal of chromosomes except No. 21, No. 24 and No. 28 were all pos- itive deeply stained. E Conclusion] R-band of Cervus nippon hortulorum chromosomes can be manifested by RBG-binding technique.展开更多
Segmental duplications on rice (Oryza sativa L.) chromosomes 8, 9, 11, and 12 were studied by examining the distributions of sequences resolved by 13 probes detecting multiple copies of DNA sequences. Four of the hyb...Segmental duplications on rice (Oryza sativa L.) chromosomes 8, 9, 11, and 12 were studied by examining the distributions of sequences resolved by 13 probes detecting multiple copies of DNA sequences. Four of the hybridization bands detected by a repetitive sequence probe, rTRS, were mapped to the ends of all the four chromosomes. Two or three of the bands detected by each of the other 12 probes were also mapped to different chromosomes. The bands detected by the same probe usually occurred in similar locations of different chromosomes. Loci detected by different DNA probes were often similarly arranged on different chromosomes. Chromosomes 8 and 9 showed colinearity of marker loci arrangement indicating a possible common origin. A segment on chromosome 9 was also very similar to the previously reported duplicated fragments on the ends of chromosomes 11 and 12 which were also detected in this study, indicating a likely common origin. Moreover, the various degrees of distributional similarity of the segments suggest a complex relationship among the chromosomes in the evolution of the rice genome. These results support the proposition that chromosome duplication and diversification may be a mechanism for the origin and evolution of the chromosomes in the rice genome.展开更多
Common bean is an important but often a disease-susceptible legume crop of temperate,subtropical and tropical regions worldwide. The crop is affected by bacterial, fungal and viral pathogens. The strategy of resistanc...Common bean is an important but often a disease-susceptible legume crop of temperate,subtropical and tropical regions worldwide. The crop is affected by bacterial, fungal and viral pathogens. The strategy of resistance-gene homologue(RGH) cloning has proven to be an efficient tool for identifying markers and R(resistance) genes associated with resistances to diseases. Microsatellite or SSR markers can be identified by physical association with RGH clones on large-insert DNA clones such as bacterial artificial chromosomes(BACs). Our objectives in this work were to identify RGH-SSR in a BAC library from the Andean genotype G19833 and to test and map any polymorphic markers to identify associations with known positions of disease resistance genes. We developed a set of specific probes designed for clades of common bean RGH genes and then identified positive BAC clones and developed microsatellites from BACs having SSR loci in their end sequences. A total of 629 new RGH-SSRs were identified and named BMr(bean microsatellite RGH-associated markers). A subset of these markers was screened for detecting polymorphism in the genetic mapping population DOR364 × G19833. A genetic map was constructed with a total of 264 markers,among which were 80 RGH loci anchored to single-copy RFLP and SSR markers. Clusters of RGH-SSRs were observed on most of the linkage groups of common bean and in positions associated with R-genes and QTL. The use of these new markers to select for disease resistance is discussed.展开更多
文摘[ Objective] This study aimed to conduct the karyotype analysis of Rabdosia lophanthoides var. gerardians and R. lophanthoides Hara var. gracilifloruschromosomes. [ Method] Vigorously growing shoot tips of R. lophanthoides var. gerardianus and R. lophanthoides Hara var. graciliflorus were stained for section preparation to observe and analyze the chromosomes. [ Result] Karyotype formula of R. lophanthoides var. gerardianus is K （2n） =2x =24 = 18m ＋4Sm, sugges- ting that this species belongs to category 2A of Stebbins; karyotype formula of R. lophanthoides Hara var. graciliflorus is K （2n） =2x =24 = 16m ＋8Sm, sugges- ting that this species belongs to category 1B of Stebbins. [Conclusion] R. lophanthoides var. gerardianus is more primitive compared with R. lophanthoides Hara var. graciliflorus.
基金supported by Chongqing Normal University Fund (XLY012)Natural Science Foundation of Chongqing Science and Technology Commission (CSTC 2006BB1260)
文摘Objeclive The aim of this study was to investigate R-band of Cervus nippon hortulorum chromosomes and to provide references for genetic variation and gene location of Cervus nippon hortulorum. [Metbod] Cell division was synchronized by the pepripheral blood lymphocyte culture and the excessive dosage of thymine deoxyribonucleoside, and R-band of Cervus nippon hortulorum chromosomes was also analyzed by RBG-banding technique. Result The number of haploid chromosome banding increased to 400. The R-band of No. 1, No. 2, No. 3, No. 4, chromosome X and Y were almost just opposite to the high-resolution G band of them. The terminal of chromosomes except No. 21, No. 24 and No. 28 were all pos- itive deeply stained. E Conclusion] R-band of Cervus nippon hortulorum chromosomes can be manifested by RBG-binding technique.
文摘Segmental duplications on rice (Oryza sativa L.) chromosomes 8, 9, 11, and 12 were studied by examining the distributions of sequences resolved by 13 probes detecting multiple copies of DNA sequences. Four of the hybridization bands detected by a repetitive sequence probe, rTRS, were mapped to the ends of all the four chromosomes. Two or three of the bands detected by each of the other 12 probes were also mapped to different chromosomes. The bands detected by the same probe usually occurred in similar locations of different chromosomes. Loci detected by different DNA probes were often similarly arranged on different chromosomes. Chromosomes 8 and 9 showed colinearity of marker loci arrangement indicating a possible common origin. A segment on chromosome 9 was also very similar to the previously reported duplicated fragments on the ends of chromosomes 11 and 12 which were also detected in this study, indicating a likely common origin. Moreover, the various degrees of distributional similarity of the segments suggest a complex relationship among the chromosomes in the evolution of the rice genome. These results support the proposition that chromosome duplication and diversification may be a mechanism for the origin and evolution of the chromosomes in the rice genome.
文摘Common bean is an important but often a disease-susceptible legume crop of temperate,subtropical and tropical regions worldwide. The crop is affected by bacterial, fungal and viral pathogens. The strategy of resistance-gene homologue(RGH) cloning has proven to be an efficient tool for identifying markers and R(resistance) genes associated with resistances to diseases. Microsatellite or SSR markers can be identified by physical association with RGH clones on large-insert DNA clones such as bacterial artificial chromosomes(BACs). Our objectives in this work were to identify RGH-SSR in a BAC library from the Andean genotype G19833 and to test and map any polymorphic markers to identify associations with known positions of disease resistance genes. We developed a set of specific probes designed for clades of common bean RGH genes and then identified positive BAC clones and developed microsatellites from BACs having SSR loci in their end sequences. A total of 629 new RGH-SSRs were identified and named BMr(bean microsatellite RGH-associated markers). A subset of these markers was screened for detecting polymorphism in the genetic mapping population DOR364 × G19833. A genetic map was constructed with a total of 264 markers,among which were 80 RGH loci anchored to single-copy RFLP and SSR markers. Clusters of RGH-SSRs were observed on most of the linkage groups of common bean and in positions associated with R-genes and QTL. The use of these new markers to select for disease resistance is discussed.
