976 resultados para Phylogenetic


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Chromosomal homologies have been established between the Chinese muntjac (Muntiacus reevesi, MRE, 2n = 46) and five ovine species: wild goat (Capra aegagrus, CAE, 2n = 60), argall (Ovis ammon, OAM, 2n = 56), snow sheep (Ovis nivicola, ONI, 2n = 52), red goral (Naemorhedus cranbrooki, NCR, 2n = 56) and Sumatra serow (Capricornis sumatraensis, CSU, 2n = 48) by chromosome painting with a set of chromosome-specific probes of the Chinese muntjac. In total, twenty-two Chinese muntjac autosomal painting probes detected thirty-five homologous segments in the genome of each species. The chromosome X probe hybridized to the whole X chromosomes of all ovine species while the chromosome Y probe gave no signal. Our results demonstrate that almost all homologous segments defined by comparative painting show a high degree of conservation in G-banding patterns and that each speciation event is accompanied by specific chromosomal rearrangements. The combined analysis of our results and previous cytogenetic and molecular systematic results enables us to map the chromosomal rearrangements onto a phylogenetic tree, thus providing new insights into the karyotypic evolution of these species.

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The Chinese pangolin (Manis pentadactyla), a representative species of the order Pholidota, has been enlisted in the mammalian whole-genome sequencing project mainly because of its phylogenetic importance. Previous studies showed that the diploid number o

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Phylogeny of the specialized schizothoracine fishes (Teleostei: Cypriniformes: Cyprinidae). Zoological Studies 40(2). 147-157. To elucidate phylogenetic relationships within the specialized schizothoracine fishes, we used 41 variable osteological and exte

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A Gram-negative, non-motile, rod-shaped bacterial strain, designated CW-E 2(T), was isolated from a polluted soil sample collected from Jiangsu Province, China. A taxonomic study of the isolate, including phylogenetic analysis based on 16S rRNA gene seque

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Thirteen complete and three partial cDNA sequences were cloned from the constructed king cobra (Ophiophagus hannah) venom gland cDNA library. Phylogenetic analysis of nucleotide sequences of king cobra with those from other snake venoms revealed that obta

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A Gram-negative, non-motile, rod-shaped bacterium, designated strain AKS 1 T, was isolated from a desert soil sample collected from Alkesu, Xin.lang Province, China. A taxonomic study, including phylogenetic analysis based on 16S rRNA gene sequences and p

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A Gram-positive bacterium, designated strain CW 7(T), was isolated from forest soil in Anhui Province, south-east China. Cells were strictly aerobic, motile with peritrichous flagella and rod-shaped. The strain grew optimally at 30-37 degrees C and pH 7.0-8.0. The major fatty acids of strain CW 7(T) were anteiso-C-15:0, iso-C-15:0 and anteiso-C-17:0. The predominant menaquinone was MK-7. The cell-wall peptidoglycan contained meso-diaminopimelic acid. The G + C content of the genomic DNA was 42.3 mol%. Phylogenetic analysis indicated that strain CW 7(T) belonged to a monophyletic cluster within the genus Bacillus and showed 16S rRNA gene sequence similarities of less than 96.5% to recognized species of the genus Bacillus. The results of the polyphasic taxonomic study, including phenotypic, chemotaxonomic and phylogenetic analyses, showed that strain CW 7(T) represents a novel species of the genus Bacillus, for which the name Bacillus pallidus sp. nov. is proposed. The type strain is CW 7(T) (=KCTC 13200(T)=CCTCC AB 207188(T)=LMG 24451(T)).

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The genetic diversity and phylogeny of 26 isolates of Bursaphelenchus xlophilus from China, Japan, Portugal and North America were investigated based on the D2/3 domain of 28S rDNA, nuclear ribosomal Internal Transcribed Spacer (ITS) sequences, and random amplified polymorphic DNA (RAPD) analysis. The genetic diversity analysis showed that the D2/3 domain of 28S rDNA of isolates of B. xlophilus from China, Portugal, Japan and the US were identical and differed at one to three nucleotides compared to those from Canada. ITS sequences of isolates from China and Portugal were the same; they differed at one or two nucleotides compared to those of Japanese isolates and at four and 23 nucleotides compared to those front the US and Canada, respectively. The phylogenetic analysis indicated that Chinese isolates share a common ancestor with one of the two Japanese clades and that the Canadian isolates form a sister group of the clade comprised of isolates from China, Portugal,Japan, and the US. The relationship between Japanese isolates and those from China was closer than with the American isolates. The Canadian isolates were the basal group of B. xylophilus. This suggests that B. xlophilus originated in North America and that the B. xylphilus that occurs in China could have been first introduced from Japan. Further analysis based on RAPD analysis revealed that the relationship among isolates from Guangdong, Zhejiang, Shandong, Anhui provinces and Nanjing was the closest, which suggests that pine wilt disease in these Chinese locales was probably dispersed from Nanjing, where this disease first occurred in China.

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During a recent soil sample survey in Eastern China, a new entomopathogenic nematode species, collected from the Chongming Islands in the southern-eastern area of Shanghai, was discovered. Morphological characteristics of different developmental stages of the nematode combined with molecular data showed that this nematode is a new genus of Rhabditidae, and described as Heterorhabditidoides chongmingensis gen. nov., sp. nov., for that it shares more morphological characteristics with heterorhabditids than with ste-inernematids. For males, the papillae formula of bursa is 1, 2, 3, 3, with constant papillae number in the terminal group, stoma tubular-shaped and about 1.5 head width; cheilorhabdions cuticularized, esophageal collar present and long, median bulb present. For infective juveniles, EP = 90 (80-105) mu m, ES = 104 (92-120) mu m, tail length = 111 (89-159) mu m, and a = 19.1 (15-21). The percentages of the nucleotides A, T, C and G in the ITS1 regions of the new species are significantly different from those of heterorhabditids and other rhabditids. Molecular phylogenetic trees based on 18S rDNA and the internal transcribed spacer (ITS) sequences data revealed that the new entomopathogenic nematode species forms a monophyletic group, which is a sister group of the clade comprised of some genera of Rhabditidae. (c) 2008 Elsevier Inc. All rights reserved.

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A novel strain, D3(T), isolated from a field-soil sample obtained from Anhui Province, PR China, was characterized taxonomically by using a polyphasic approach. The cells were Gram-negative, yellow-pigmented rods devoid of flagella, but showing gliding motility. The organism was able to grow at 5-37 degrees C and at pH 4.0-10.0. A comparative 16S rRNA gene sequence analysis indicated that strain D3(T) is a member of the genus Flavobacterium, sharing highest sequence similarity with the type strain of Flavobacterium defluvii (96.7 %). The major isoprenoid quinone was MK-6 and the predominant fatty acids were iso-C-15:0, summed feature 3 (C-16:1 omega 7c and/or iso-C-15:0 2-OH) and C-16:0. The DNA G + C content was 31.4 mol%. On the basis of phylogenetic and phenotypic data, strain D3(T) represents a novel species within the genus Flavobacterium, for which the name Flavobacterium anhuiense sp. nov. is proposed. The type strain is D3(T) (=KCTC 22128(T)= CGIVICC 1.6859(T)).

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Mitochondrial DNA control region segment I sequences and melanocortin 1 receptor (MC1R) gene polymorphism were examined in ethnic populations in the silk road region of China. Both the frequencies of the MC1R variants and the results of mtDNA data in this region presented intermediate values between those of Europe and East and Southeast Asia, which suggested extensive gene admixture in this area and was in general agreement with previous studies. Phylogenetic analysis of the ethnic populations in the Silk Road region that based on mtDNA data didn't show expected cluster pattern according to their ethnogenesis. We suspect that a high migration rate in female among these closely related populations and other three demographic events might account for it.

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The phylogenetic relationships among worldwide species of genus Ochotona were investigated by sequencing mitochondrial cytochrome b and ND4 genes. Parsimony and neighbor-joining analyses of the sequence data yielded congruent results that strongly indicated three major clusters: the shrub-steppe group, the northern group, and the mountain group. The subgeneric classification of Ochotona species needs to be revised because each of the two subgenera in the present classification contains species from the mountain group. To solve this taxonomic problem so that each taxon is monophyletic, i.e., represents a natural clade, Ochotona could be divided into three subgenera, one for the shrub-steppe species, a second for the northern species, and a third for the mountain species. The inferred tree suggests that the differentiation of this genus in the Palearctic Region was closely related to the gradual uplifting of the Tibet (Qinghai-Xizang) Plateau, as hypothesized previously, and that vicariance might have played a major role in the differentiation of this genus on the Plateau, On the other hand, the North American species, O. princeps, is most likely a dispersal event, which might have happened during the Pliocene through the opening of the Bering Strait. The phylogenetic relationships within the shrub-steppe group are worth noting in that instead of a monophyletic shrub-dwelling group, shrub dwellers and steppe dwellers are intermingled with each other. Moreover, the sequence divergence within the sister tars of one steppe? dweller and one shrub dweller is very low. These findings support the hypothesis that pikes have entered the steppe environment several times and that morphological similarities within steppe dwellers were due to convergent evolution. (C) 2000 Academic Press.

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Partial sequences of cytochrome b (Cyt b) and 16S ribosomal RNA (16S rRNA) mitochondrial genes were used for species identification and estimating phylogenetic relationship among three commercially important Ompok species viz. O. Pabda, O. pabo and O. bimaculatus. The sequence analysis of Cyt b (1118bp) and 16S rRNA (569 & 570bp) genes revealed that O. pabda, O. pabo & 0. bimaculatus were genetically distinct species and they exhibited identical phylogenetic relationship. The present study discussed usefulness of mtDNA genes (Cyt b & 16S rRNA) in resolving taxonomic ambiguity and estimating phylogenetics relationship.

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Three 26 kDa proteins, named as TJ-CRVP, NA-CRVP1 and NA-CRVP2, were isolated from the venoms of Trimeresurus jerdonii and Naja atra, respectively. The N-terminal sequences of TJ-CRVP and NA-CRVPs were determined. These components were devoid of the enzymatic activities tested, such as phospholipase A(2), arginine esterase, proteolysis, L-amino acid oxidase, 5' nucleotidase, acetylcholinesterase. Furthermore, these three components did not have the following biological activities: coagulant and anticoagulant activities, lethal activity, myotoxicity, hemorrhagic activity, platelet aggregation and platelet aggregation-inhibiting activities. These proteins are named as cysteine-rich venom protein (CRVP) because their sequences showed high level of similarity with mammalian cysteine-rich secretory protein (CRISP) family. Recently, some CRISP-like proteins were also isolated from several different snake venoms, including Agkistrodon blomhoffi, Trimeresurus flavoviridis, Lanticauda semifascita and king cobra. We presumed that CRVP might be a common component in snake venoms. Of particular interest, phylogenetic analysis and sequence alignment showed that NA-CRVP1 and ophanin, both from elapid snakes, share higher similarity with CRVPs from Viperidae snakes. (C) 2003 Elsevier Ltd. All rights reserved.

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A new metalloproteinase-disintegrin, named Jerdonitin, was purified from Trimeresurus jerdonii venom with a molecular weight of 36 kDa on SDS-PAGE. It dose-dependently inhibited ADP-induced human platelet aggregation with IC50 of 120 nM. cDNA cloning and sequencing revealed that Jerdonitin belonged to the class II of snake venom metalloproteinases (SVMPs) (P-II class). Different from other P-II class SVMPs, metalloproteinase and disintegrin domains of its natural protein were not separated, confirmed by internal peptide sequencing. Compared to other P-II class SVMPs, Jerdonitin has two additional cysteines (Cys219 and Cys238) located in the spacer domain and disintegrin domain, respectively. They probably form a disulfide bond and therefore the metalloproteinase and disintegrin domains cannot be separated by posttranslationally processing. In summary, comparison of the amino acid sequences of Jerdonitin with those of other P-II class SVMPs by sequence alignment and phylogenetic analysis, in conjunction with natural protein structure data, suggested that it was a new type of P-II class SVMPs. (C) 2003 Elsevier Inc. All rights reserved.