[Objective] The genetic diversity of major mango cultivars in China was analyzed by using SSR markers, and their fingerprints were constructed so as to provide theoretical basis for germplasm innovation and breeding o...[Objective] The genetic diversity of major mango cultivars in China was analyzed by using SSR markers, and their fingerprints were constructed so as to provide theoretical basis for germplasm innovation and breeding of mango. [Method] With 115 pairs of SSR primers, genetic diversity analysis and cluster analysis were performed for 30 mango cultivars, among which the genetic relationships were analyzed. [Result] Total 64 pairs of polymorphic primers were screened out from the 115 pairs of primers, and total 343 bands were amplified from the 30 cultivars with 73.2% of polymorphic bands. On average, 3.9 allelic loci were detected for each pair of primers with genetic diversity index of 0.5, Shannon's diversity index of 1.00 and polymorphism information content of 0.49, indicating higher genetic diversity. The cluster analysis showed that the 30 major cultivars could be classified into four categories. The first category included 14 cultivars; the second category included 11 cultivars, most of which were introduced from abroad; the third category included 4 cultivars, Le., Miansan, Parayinda, Baiyu and Hongxiangya: the fourth category included only one cultivar Maqiesu.By using 7 pairs of SSR markers, i.e., M42, M49, M54, M55, M96, M99 and M103, digital fingerprints were constructed for the 30 mango cultivars. [Conclusion] The 30 mango cultivars present more complex genomic genetics and abundant genetic information, and they have higher genetic diversity.展开更多
The total organic carbon (TOC) content series from the lake sediment of Minqin Basin (100°57′–104°57′E, 37°48′–39°17′N) in northwestern China, which has a 10 000-year-long paleo-climatic prox...The total organic carbon (TOC) content series from the lake sediment of Minqin Basin (100°57′–104°57′E, 37°48′–39°17′N) in northwestern China, which has a 10 000-year-long paleo-climatic proxy record, was used to analyze the Holocene climate changes in the local region. The proxy record was established in the Sanjiaocheng (SJC), Triangle Town in Chinese, Section (103°20′25″E, 39°00′38″N), which is located at the northwestern boundary of the present Asian summer monsoon in China, and is sensitive to global environmental and climate changes. Applying singular spectrum analysis (SSA) to the TOC series, principal climatic oscillations and periodical changes were studied. The results reveal 3 major patterns of climate change regulated by reconstructed components (RCs). The first pattern is natural long-term trend of climatic change in the local area (Minqin Basin), indicating a relatively wetter stage in early Holocene (starting at 9.5 kaBP), and a relatively dryer stage with a strong lake desiccation and a declined vegetation cover in mid-Holocene (during 7–6 kaBP). From 4.0 kaBP to the present, there has been a gradually decreasing trend in the third reconstructed component (RC3) showing that the local climate changed again into a dryer stage. The second pattern shows millennial-centennial scale oscillations containing cycles of 1 600 and 800 years that have been present throughout almost the entire Holocene period of the last 10 000 years. The third pattern is a millennial-centennial scale variation with a relatively smaller amplitude and unclear cycles showing a nonlinear interaction within the earth’s climate systems.展开更多
Using digital wave data recorded by the Barkam station, source parameters for 93 earthquakes with ML2.5 - 5.0 in the Barkam area are determined by spectral analysis. PreHmiuary analysis of the source parameters show t...Using digital wave data recorded by the Barkam station, source parameters for 93 earthquakes with ML2.5 - 5.0 in the Barkam area are determined by spectral analysis. PreHmiuary analysis of the source parameters show that there is a high correlation between seismic moment Mo and local scale ML, which is lgtoMo = 0.92ML + 10.24,correlation coefficient R is 0.86; Investigation of the relationship between stress drop and local scale ML indicates that the stress drop seems to be independent of ML.展开更多
The sporadotrichid ciliates are an especially diverse group. A number of investigators have studied the morphological, morphogenetic, and molecular relationships among members of this group. Despite this, a consistent...The sporadotrichid ciliates are an especially diverse group. A number of investigators have studied the morphological, morphogenetic, and molecular relationships among members of this group. Despite this, a consistent classification is still lacking and several important questions about the phylogenetic relationships within this group remain unsolved. To improve our understanding of these relationships, we constructed phylogenetic trees using the nucleotide sequences of the small-subunit rRNA (SSrRNA) gene and amino acid sequences of actin I and α-tubulin. Analyses of SSrRNA gene sequences indicated that: 1) the Sporadotrichida sensu Lynn (2008) and the Oxytrichidae are polyphyletic; 2) the Uroleptus species, which are classified to urostylids, formed a sister group with the oxytrichids; 3) Halteria grandinella, which is grouped morphologically with oligotrich species, clustered within the oxytrichids. These results are congruent with previous studies based on SSrRNA gene sequences. However, the amino acid sequences of actin I and α-tubulin yielded different topologies. The main results are: 1) in all phylogenetic trees, the genus Oxytricha was paraphyletic; 2) Uroleptus was sister to a subset of Urostyla and Holosticha, albeit with low supporting values; 3) Halteria grandinella was separated distantly from the Oxytrichidae in trees inferred from actin I amino acid sequences but clustered with oligotrichids in the α-tubulin analysis. The inconsistency among the trees inferred from these different molecular markers may be caused by rapidly accumulated genetic characterizations of ciliates. Further studies with additional molecular markers and sampling of more taxa are expected to better address the relationships among sporadotrichids.展开更多
基金Supported by Natural Science Foundation of Hainan Province(34128)Fundamental Scientific Research Funds of Chinese Academy of Tropical Agricultural Sciences(1630032013031)~~
文摘[Objective] The genetic diversity of major mango cultivars in China was analyzed by using SSR markers, and their fingerprints were constructed so as to provide theoretical basis for germplasm innovation and breeding of mango. [Method] With 115 pairs of SSR primers, genetic diversity analysis and cluster analysis were performed for 30 mango cultivars, among which the genetic relationships were analyzed. [Result] Total 64 pairs of polymorphic primers were screened out from the 115 pairs of primers, and total 343 bands were amplified from the 30 cultivars with 73.2% of polymorphic bands. On average, 3.9 allelic loci were detected for each pair of primers with genetic diversity index of 0.5, Shannon's diversity index of 1.00 and polymorphism information content of 0.49, indicating higher genetic diversity. The cluster analysis showed that the 30 major cultivars could be classified into four categories. The first category included 14 cultivars; the second category included 11 cultivars, most of which were introduced from abroad; the third category included 4 cultivars, Le., Miansan, Parayinda, Baiyu and Hongxiangya: the fourth category included only one cultivar Maqiesu.By using 7 pairs of SSR markers, i.e., M42, M49, M54, M55, M96, M99 and M103, digital fingerprints were constructed for the 30 mango cultivars. [Conclusion] The 30 mango cultivars present more complex genomic genetics and abundant genetic information, and they have higher genetic diversity.
基金the National Natural Science Foundation of China (NSFC) (No. 40571169)the NSFC’s Innovation Team Project (No. 40421101), and the NSFC’s Key Program Project (No. 90502008)
文摘The total organic carbon (TOC) content series from the lake sediment of Minqin Basin (100°57′–104°57′E, 37°48′–39°17′N) in northwestern China, which has a 10 000-year-long paleo-climatic proxy record, was used to analyze the Holocene climate changes in the local region. The proxy record was established in the Sanjiaocheng (SJC), Triangle Town in Chinese, Section (103°20′25″E, 39°00′38″N), which is located at the northwestern boundary of the present Asian summer monsoon in China, and is sensitive to global environmental and climate changes. Applying singular spectrum analysis (SSA) to the TOC series, principal climatic oscillations and periodical changes were studied. The results reveal 3 major patterns of climate change regulated by reconstructed components (RCs). The first pattern is natural long-term trend of climatic change in the local area (Minqin Basin), indicating a relatively wetter stage in early Holocene (starting at 9.5 kaBP), and a relatively dryer stage with a strong lake desiccation and a declined vegetation cover in mid-Holocene (during 7–6 kaBP). From 4.0 kaBP to the present, there has been a gradually decreasing trend in the third reconstructed component (RC3) showing that the local climate changed again into a dryer stage. The second pattern shows millennial-centennial scale oscillations containing cycles of 1 600 and 800 years that have been present throughout almost the entire Holocene period of the last 10 000 years. The third pattern is a millennial-centennial scale variation with a relatively smaller amplitude and unclear cycles showing a nonlinear interaction within the earth’s climate systems.
基金This project was sponsored by the National Key Basic Research and Development Programof China (2004CB418404)
文摘Using digital wave data recorded by the Barkam station, source parameters for 93 earthquakes with ML2.5 - 5.0 in the Barkam area are determined by spectral analysis. PreHmiuary analysis of the source parameters show that there is a high correlation between seismic moment Mo and local scale ML, which is lgtoMo = 0.92ML + 10.24,correlation coefficient R is 0.86; Investigation of the relationship between stress drop and local scale ML indicates that the stress drop seems to be independent of ML.
基金Supported by the National Natural Science Foundation of China (No. 30870264, 40976075)a grant from the Center of Excellence in Biodiversity, King Saud Universitya Marie Curie Incoming International Fellowship within the 7th European Community Framework Programme
文摘The sporadotrichid ciliates are an especially diverse group. A number of investigators have studied the morphological, morphogenetic, and molecular relationships among members of this group. Despite this, a consistent classification is still lacking and several important questions about the phylogenetic relationships within this group remain unsolved. To improve our understanding of these relationships, we constructed phylogenetic trees using the nucleotide sequences of the small-subunit rRNA (SSrRNA) gene and amino acid sequences of actin I and α-tubulin. Analyses of SSrRNA gene sequences indicated that: 1) the Sporadotrichida sensu Lynn (2008) and the Oxytrichidae are polyphyletic; 2) the Uroleptus species, which are classified to urostylids, formed a sister group with the oxytrichids; 3) Halteria grandinella, which is grouped morphologically with oligotrich species, clustered within the oxytrichids. These results are congruent with previous studies based on SSrRNA gene sequences. However, the amino acid sequences of actin I and α-tubulin yielded different topologies. The main results are: 1) in all phylogenetic trees, the genus Oxytricha was paraphyletic; 2) Uroleptus was sister to a subset of Urostyla and Holosticha, albeit with low supporting values; 3) Halteria grandinella was separated distantly from the Oxytrichidae in trees inferred from actin I amino acid sequences but clustered with oligotrichids in the α-tubulin analysis. The inconsistency among the trees inferred from these different molecular markers may be caused by rapidly accumulated genetic characterizations of ciliates. Further studies with additional molecular markers and sampling of more taxa are expected to better address the relationships among sporadotrichids.