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61.
伤齿龙类是手盗龙类中较为独特的一支, 时代从中侏罗世到晚白垩世, 主要分布于亚洲(东部和中部)以及北美地区。本文基于前人的研究成果, 结合新标本, 对中国伤齿龙类的系统分类、骨骼形态、骨组织、系统发育关系和古生物地理等方面进行了全面深入的评估与探讨。 相似文献
62.
假交替单胞菌属归属于交替假单胞菌科。交替假单胞菌N289菌株分离自南极海冰,我们通过二代测序技术获得了其全基因组序列,组装后获得2条染色体和1条质粒,大小分别是3.2M、636kb和1.8kb。全基因组共包含3,589个ORF,GC含量为40.83%。基因功能分析表明,该菌酶活性高,具有很强的环境适应性。这项研究有助于了解生物多样性、该菌株的进化地位和微生物相互作用关系。 相似文献
63.
Guilian Sheng Lianjuan Wu Xindong Hou Junxia Yuan Shenghong Cheng Bojian Zhong Xulong Lai 《Frontiers of Earth Science》2009,3(1):100-106
The evolution of Elephantidae has been intensively studied in the past few years, especially after 2006. The molecular approaches
have made great contribution to the assumption that the extinct woolly mammoth has a close relationship with the Asian elephant
instead of the African elephant. In this study, partial ancient DNA sequences of cytochrome b (cyt b) gene in mitochondrial genome were successfully retrieved from Late Pleistocene Mammuthus primigenius bones collected from Heilongjiang Province in Northeast China. Both the partial and complete homologous cyt b gene sequences and the whole mitochondrial genome sequences extracted from GenBank were aligned and used as datasets for
phylogenetic analyses. All of the phylogenetic trees, based on either the partial or the complete cyt b gene, reject the relationship constructed by the whole mitochondrial genome, showing the occurrence of an effect of sequence
length of cyt b gene on mammoth phylogenetic analyses. 相似文献
64.
65.
We describe the changes in plant cover, species richness, and flowering after rainfall over an entire growing season (September 1989–January 1990) in a southern Atacama Desert site in Chile. One month after the rain, vegetation was dominated by annuals and geophytes which dried out after 19 weeks. Among all species, including shrubs, we found differences of 4–10 weeks in the length and peak of the flowering period. The flowering sequence of the species belonging to the families Brassicaceae, Liliaceae, Onagraceae, and Asteraceae matched closely the sequences described for temperate plant communities, suggesting that this phenological character is phylogenetically determined. 相似文献
66.
Randomly amplified polymorphic DNA (RAPD) technique was applied to assess the genetic variations and phylogenetic relationships
in 4 species ofPorphyra. The samples were collected from the coast of Canada, Vietnam, Zhoushan, Fujian and Qingdao in China. Amplifications with
20 primers were carried out under predetermined optimal reaction conditions (samples were first heated at 94°C for 5 min.
and followed by 45 cycles of 1 min at 94°C, 1 min at 36°C, and 2 min at 72°C, then held at 72°C for 10 min). The amplified
products were scored as present (1) or absent (0) for each DNA sample and an index of genetic similarity (F) was calculated
by using Nei & Li’s matching coefficient method (1979). The value of (1−F) was used to quantify the genetic distances between
species and construct a phylogenetic tree. The relationship indicated by the UPGMA and NJ cluster analysis on the values of
the genetic distance is in good overall agreement with classical taxonomy. The obvious differences between natural and cultivated
population ofP. haitanensi suggest that variation or hybridization with other species occurred during the culture.
Contribution No. 100 from the Experimental Marine Biology Laboratory, IOCAS.
Contribution No. 3289 from the Institute of Oceanology, Chinese Academy of Sciences.
The research supported by the Foundation of the Chinese Academy of Sciences. 相似文献
67.
基于氨基酸的物理化学性质,将氨基酸分为4类,疏水,带电荷,有极性,甘氨酸,在此基础上给出DNA序列一种新的图形表示方法:将1列DNA序列表示为二维空间中的3条特征曲线,利用计算C(i,j)矩阵的主特征值,给出DNA序列的3维特征向量,得到相似距离矩阵.最后计算10种不同物种β-球蛋白第一段外显子的欧式空间距离矩阵D(i,j),并利用UPGMA算法给出了这10种不同物种基于这种相似关系的系统发生树. 相似文献
68.
利用生物信息学方法,从龙须菜(Gracilaria lemaneiformis)公共核苷酸数据库中筛查到8条含有微卫星DNA的序列,并根据筛查出的微卫星DNA序列设计合成了5对引物,此外还使用了细江蓠的4对已知微卫星DNA引物共9对引物在采集自青岛的26株野生龙须菜个体中进行扩增,结果筛选到2对引物可扩增出具有多态性的产物.然后利用5对龙须菜的微卫星引物对6个龙须菜品系和另外2个种外物种细基江蓠和菊花心江蓠进行系统学分析.根据计算得到的不同样品之间Nei氏遗传相似系数进行聚类分析,显示青岛野生龙须菜QD与栽培品系981、石岛的龙须菜样品SD与龙须岛的龙须菜样品LD之间的遗传相似系数最高,而来自委内瑞拉的龙须菜样品LV与青岛野生龙须菜之间的差异远远高于种内水平的差异. 相似文献
69.
Bacterial diversity in sea ice brine samples which collected from four stations located at the Canada Basin, Arctic Ocean was analyzed by PCR-DGGE. Twenty-three 16S rDNA sequences of bacteria obtained from DGGE bands were cloned and sequenced. Phylogenetic analysis clustered these sequences within γ-proteobacteria, Cytophaga-Flexlbacter-Bacteroides （CFB） group, Firmicutes and Actinobacteria. The phylotype of Pseudoalteromonas in the γ-proteobacteria was predominant and members of the CFB group and γ-proteobacteria were highly abundant in studied sea ice brine samples. 相似文献
70.