Microplankton communities of three coastal sites of Qingdao,Shandong Province,China were investigated using RAPD（random amplified polymorphic DNA） molecular markers and morphological observations.Eight RAPD-primers ...Microplankton communities of three coastal sites of Qingdao,Shandong Province,China were investigated using RAPD（random amplified polymorphic DNA） molecular markers and morphological observations.Eight RAPD-primers were selected to amplify the DNA polymorphy.The genetic distances inferred from the pairwise similarities were calculated for the phylogenetic tree construction.Meantime,the traditional microscopic determination,a way of visualizing the species composition,was performed to detect the major taxa of microplanktons from all samples.Results showed that：（1） the band sharing index values were in the range of 0.504 2-0.763 2 among samples from the same sampling site at different time scales,while 0.406 5-0.685 7 among the samples from different stations at the same time scales,indicating that spatial variations of microplankton communities were more pronounced than temporal ones;（2） samples from the same station basically clustered together,corresponding to the geographic distribution of the sampling sites;（3） diversity derived from genetic and morphological data did not correspond with each other well.展开更多
Genetic diversity among and between 16 cultivars of pigeonpea (Cajanus cajan (L) Millsp.) and its wild relatives (C. albicans and C. lineatus) analysed using RAPD. Twenty two random primers with an average of 71.2% po...Genetic diversity among and between 16 cultivars of pigeonpea (Cajanus cajan (L) Millsp.) and its wild relatives (C. albicans and C. lineatus) analysed using RAPD. Twenty two random primers with an average of 71.2% polymorphism produced 151 polymorphic bands. Cluster analysis based on these 151 RAPD markers revealed relatively low level (0.434 - 0.714) of genetic diversity among cultivars and high level of diversity between cultivars and wild relatives. C. albicans and C. lineatus showed only 0.231 similarity with each other and C. albicans showed relatively higher similarity with C. cajan cultivars than that showed by C. lineatus. In dendrogram the 16 cultivars grouped into two distinct clusters comprising of seven and nine genotypes each while the wild species form out groups. Bootstrap analysis of the dendrogram was performed and resulted in significant bootstrap values. Principal components analysis (PCA) also revealed the similar results that of unweighted pair group method with arithmetic mean (UPGMA). The first, second and third PCs contributed 55.9%, 5.9%, and 5.6% of the variation, respectively, with cumulative variation of the first three PCs was 67.4%.展开更多
Recently we applied randomly amplified polymorphic DNA (RAPD) fingerprinting to detect clonal variability among individual cercariae within daughter sporocysts and rediae of 10 digenean trematodes (Platyhelminthes: Tr...Recently we applied randomly amplified polymorphic DNA (RAPD) fingerprinting to detect clonal variability among individual cercariae within daughter sporocysts and rediae of 10 digenean trematodes (Platyhelminthes: Trematoda). The most variable RAPD patterns were obtained for Schistosomatidae representative-avian schistosome Trichobilharzia szidati. In this work, 50 polymorphic DNA fragments of approximately 300-1500 bp from RAPD patterns of individual T. szidati cercariae were cloned and sequenced. As a result genomic DNA sequences (total length of approximately 41,000 bp) revealing clonal variability in T. szidati cercariae were obtained and analyzed. The analysis indicated that these sequences contained tandem, inverted and dispersed repeats as well as regions homological to retroelements of two human parasites, Schistosoma mansoni and S. japonicum. Tandem and inverted repeats constituted 8.9% and 22.1% respectively, while the percentage of dispersed repeats was 21.0%. The average content of these components was 41.7% with the average AT content being 59.0%. About 40% of sequences included regions ranging in length from 96 to 1005 bp which displayed amino acid homology with open reading frame pol products of S. mansoni and S. japonicum retroelements: non-long terminal repeat retrotransposons (nLTRs, 76%), long terminal repeat retrotransposons (LTRs, 14%), and Penelope-like elements (PLEs, 10%). Most of these regions (86.4%) contained frameshifts, gaps, and stop-codons. The largest portion of them was homological to nLTRs of the RTE clade (67%). The number of sequences homologous to the members of CR1 lineage was 7 times smaller (9%). Homology with LTRs of Gypsy/Ty3 and BEL clades was revealed in 5% and 9% of cases respectively. We assume that the repetitive elements including retroelement-like sequences described in the current study may serve as the source of clonal variability detected previously in T. szidati and other digenean trematodes. Such genome regions rapidly accumulate mutations and thus may play an important functional role in the life history of the species.展开更多
Hyalomma dromedarii ticks are important disease vectors to camels in the UAE and worldwide. Ticks can be identified using DNA-based techniques. In addition, such techniques could be utilized to study the intraspecific...Hyalomma dromedarii ticks are important disease vectors to camels in the UAE and worldwide. Ticks can be identified using DNA-based techniques. In addition, such techniques could be utilized to study the intraspecific genetic diversity in tick populations. In this study, the genetic diversity of four H. dromedarii populations was investigated using mitochondrial cytochrome c oxidase subunit I (COI) gene and randomly amplified polymorphic DNA polymerase chain reaction (RAPD-PCR). The results showed that both of the aforementioned techniques produced similar grouping patterns. Moreover, they revealed that the four tick populations had high levels of genetic similarity. However, one population was slightly different from the three other populations. The current study demonstrated that H. dromedarii ticks in the UAE are very similar at the genetic level and that investigating more locations and screening larger numbers of ticks could reveal larger genetic differences.展开更多
基金The National Natural Science Foundation of China under contract Nos 30570236,U0633006,40506033 and 40676076the Program for New Century Excellent Talents in Universities of China under contract No. NCET05-0595
文摘Microplankton communities of three coastal sites of Qingdao,Shandong Province,China were investigated using RAPD（random amplified polymorphic DNA） molecular markers and morphological observations.Eight RAPD-primers were selected to amplify the DNA polymorphy.The genetic distances inferred from the pairwise similarities were calculated for the phylogenetic tree construction.Meantime,the traditional microscopic determination,a way of visualizing the species composition,was performed to detect the major taxa of microplanktons from all samples.Results showed that：（1） the band sharing index values were in the range of 0.504 2-0.763 2 among samples from the same sampling site at different time scales,while 0.406 5-0.685 7 among the samples from different stations at the same time scales,indicating that spatial variations of microplankton communities were more pronounced than temporal ones;（2） samples from the same station basically clustered together,corresponding to the geographic distribution of the sampling sites;（3） diversity derived from genetic and morphological data did not correspond with each other well.
文摘Genetic diversity among and between 16 cultivars of pigeonpea (Cajanus cajan (L) Millsp.) and its wild relatives (C. albicans and C. lineatus) analysed using RAPD. Twenty two random primers with an average of 71.2% polymorphism produced 151 polymorphic bands. Cluster analysis based on these 151 RAPD markers revealed relatively low level (0.434 - 0.714) of genetic diversity among cultivars and high level of diversity between cultivars and wild relatives. C. albicans and C. lineatus showed only 0.231 similarity with each other and C. albicans showed relatively higher similarity with C. cajan cultivars than that showed by C. lineatus. In dendrogram the 16 cultivars grouped into two distinct clusters comprising of seven and nine genotypes each while the wild species form out groups. Bootstrap analysis of the dendrogram was performed and resulted in significant bootstrap values. Principal components analysis (PCA) also revealed the similar results that of unweighted pair group method with arithmetic mean (UPGMA). The first, second and third PCs contributed 55.9%, 5.9%, and 5.6% of the variation, respectively, with cumulative variation of the first three PCs was 67.4%.
文摘Recently we applied randomly amplified polymorphic DNA (RAPD) fingerprinting to detect clonal variability among individual cercariae within daughter sporocysts and rediae of 10 digenean trematodes (Platyhelminthes: Trematoda). The most variable RAPD patterns were obtained for Schistosomatidae representative-avian schistosome Trichobilharzia szidati. In this work, 50 polymorphic DNA fragments of approximately 300-1500 bp from RAPD patterns of individual T. szidati cercariae were cloned and sequenced. As a result genomic DNA sequences (total length of approximately 41,000 bp) revealing clonal variability in T. szidati cercariae were obtained and analyzed. The analysis indicated that these sequences contained tandem, inverted and dispersed repeats as well as regions homological to retroelements of two human parasites, Schistosoma mansoni and S. japonicum. Tandem and inverted repeats constituted 8.9% and 22.1% respectively, while the percentage of dispersed repeats was 21.0%. The average content of these components was 41.7% with the average AT content being 59.0%. About 40% of sequences included regions ranging in length from 96 to 1005 bp which displayed amino acid homology with open reading frame pol products of S. mansoni and S. japonicum retroelements: non-long terminal repeat retrotransposons (nLTRs, 76%), long terminal repeat retrotransposons (LTRs, 14%), and Penelope-like elements (PLEs, 10%). Most of these regions (86.4%) contained frameshifts, gaps, and stop-codons. The largest portion of them was homological to nLTRs of the RTE clade (67%). The number of sequences homologous to the members of CR1 lineage was 7 times smaller (9%). Homology with LTRs of Gypsy/Ty3 and BEL clades was revealed in 5% and 9% of cases respectively. We assume that the repetitive elements including retroelement-like sequences described in the current study may serve as the source of clonal variability detected previously in T. szidati and other digenean trematodes. Such genome regions rapidly accumulate mutations and thus may play an important functional role in the life history of the species.
文摘Hyalomma dromedarii ticks are important disease vectors to camels in the UAE and worldwide. Ticks can be identified using DNA-based techniques. In addition, such techniques could be utilized to study the intraspecific genetic diversity in tick populations. In this study, the genetic diversity of four H. dromedarii populations was investigated using mitochondrial cytochrome c oxidase subunit I (COI) gene and randomly amplified polymorphic DNA polymerase chain reaction (RAPD-PCR). The results showed that both of the aforementioned techniques produced similar grouping patterns. Moreover, they revealed that the four tick populations had high levels of genetic similarity. However, one population was slightly different from the three other populations. The current study demonstrated that H. dromedarii ticks in the UAE are very similar at the genetic level and that investigating more locations and screening larger numbers of ticks could reveal larger genetic differences.
