نتایج جستجو برای: taxonomic units

تعداد نتایج: 197687  

Journal: :Systematic biology 2014
Bailey D McKay Herman L Mays Cheng-Te Yao Dongmei Wan Hiroyoshi Higuchi Isao Nishiumi

Species designations are critically important scientific hypotheses that serve as the foundational units in a wide range of biological subdisciplines. A growing realization that some classes of data fail to delimit species under certain conditions has led to increasingly more integrative taxonomies, whereby species discovery and hypothesis testing are based on multiple kinds of data (e.g., morp...

G.L. Zhang H.M. Hou, L.M. Sun M.L. Gao Y. Liu

The intestinal bacterial diversity of Stichopus japonicus was investigated using 16S ribosomal RNA gene (rDNA) clone library and Polymerase Chain Reaction/Denaturing Gradient Gel Electrophoresis (PCR-DGGE). The clone library yielded a total of 188 clones, and these were sequenced and classified into 106 operational taxonomic units (OTUs) with sequence similarity ranging from 88 to 100%. The cov...

Journal: :Molecular phylogenetics and evolution 1999
M A Garrido-Ramos R de la Herrán M Jamilena R Lozano C Ruiz Rejón M Ruiz Rejón

In this paper, we use the EcoRI centromeric satellite DNA family conserved in Sparidae as a taxonomic and a phylogenetic marker. The analyses of 56 monomeric units (187 bp in size) obtained by means of cloning and PCR from 10 sparid species indicate that this repetitive DNA evolves by concerted evolution. Different phylogenetic inference methods, such as neighbor-joining and UPGMA, group the 56...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه زابل - دانشکده کشاورزی 1391

زنبور پارازیتویید lipolexis gracilis پارازیتویید اولیه تعداد زیادی از شته های زیان آور گیاهی است.در این تحقیق خصوصیات مرفولوژیک زنبور پارازیتویید lipolexis gracilis(hym, braconidae, aphidiinae) در مناطق مختلف جهان مورد بررسی قرار گرفت. این خصوصیات شامل،شمارش تعداد بندهای شاخک، نسبت طول به عرض بندهای اول و دوم فلاژلوم، نسبت طول بند اول فلاژلوم به بند دوم آن،شمارش تعداد صفحات حسی روی آنها، تعداد ...

Journal: :FEMS microbiology ecology 2006
Tingfen Yan Qi Ye Jizhong Zhou Chuanlun L Zhang

Methanotrophs are ubiquitous in soil, fresh water and the open ocean, but have not been well characterized in deep-sea hydrocarbon seeps and gas hydrates, where methane is unusually abundant. Here we report the presence of new functional genes for the aerobic oxidation of methane by methanotrophs in marine sediments associated with gas hydrates and hydrocarbon seeps in the Gulf of Mexico. Sampl...

Journal: :Proceedings of the Royal Society B: Biological Sciences 2008
J Rach R DeSalle I.N Sarkar B Schierwater H Hadrys

DNA barcoding has become a promising means for identifying organisms of all life stages. Currently, phenetic approaches and tree-building methods have been used to define species boundaries and discover 'cryptic species'. However, a universal threshold of genetic distance values to distinguish taxonomic groups cannot be determined. As an alternative, DNA barcoding approaches can be 'character b...

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