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81.
Cryphonectria havanensis is a fungus associated with Eucalyptus species in Cuba and Florida (U.S.A.). Until recently, there have been no living cultures of C. havanensis and it has thus not been possible to assess its taxonomic status. Isolates thought to represent this fungus have, however, emerged from surveys of Eucalyptus in Mexico and Hawaii (U.S.A.). Results of this study showed that these isolates represent C. havanensis but reside in a genus distinct from Cryphonectria sensu stricto, which is described here as Microthia. Isolates of an unidentified fungus occurring on Myrica faya in the Azores and Madeira also grouped in Microthia and were identical to other M. havanensis isolates. Cryphonectria coccolobae, a fungus occurring on sea grape (Coccoloba uvifera) in Bermuda and Florida, was found to be morphologically identical to Microthia and is transferred to this genus, but as a distinct species. Surveys for M. coccolobae on sea grape in Florida, yielded a second diaporthalean fungus from this host. This fungus is morphologically and phylogenetically distinct from M. coccolobae and other closely related taxa and is described as Ursicollum fallax gen. et sp. nov. Phylogenetic analyses in this study have also shown that isolates of C. eucalypti, a pathogen of Eucalyptus in South Africa and Australia, group in a clade separate from all other groups including that representing Cryphonectria sensu stricto. This difference is supported by the fact that Cryphonectria eucalypti has ascospore septation different to that of all other Cryphonectria species. A new genus, Holocryphia, is thus erected for C. eucalypti.Taxonomic novelties: Microthia Gryzenh. & M.J. Wingf. gen. nov., Microthia havanensis (Bruner) Gryzenh. & M.J. Wingf. comb. nov., Microthia coccolobae (Vizioli) Gryzenh. & M.J. Wingf. comb. nov., Holocryphia Gryzenh. & M.J. Wingf. gen. nov., Holocryphia eucalypti (M. Venter & M.J. Wingf.) Gryzenh. & M.J. Wingf. comb. nov., Ursicollum Gryzenh. & M.J. Wingf. gen. nov., Ursicollum fallax Gryzenh. & M.J. Wingf. sp. nov.  相似文献   
82.
测定了江苏山羊品种的细胞色素b基因全序列1 140 bp,并引用10个山羊品种(群体)细胞色素b基因全序列进行比较,分析碱基组成和变异情况以及核苷酸序列差异.以绵羊为外群,分别采用邻近法、最大简约法和最大似然法构建分子系统树,得到的拓扑结构一致,初步提示了江苏山羊品种的系统进化关系:长江三角洲白山羊和黄淮山羊的亲缘关系较近,可能来自同一个母系;它们与日本山羊可能在较早的世代具有共同的祖先.本研究结果也支持将东亚、南亚和东南亚固有山羊群体划分为"东亚"和"南亚"两大亲缘系统的观点.  相似文献   
83.
The phylogenetic position of Diplura within Hexapoda has been controversial. There are three major lineages in Diplura: Campodeoidea, Projapygoidea, and Japygoidea. However, most of the previous studies were restricted to Campodeoidea and Japygoidea. Until now, only preliminary morphological study on Projapygoidea was reported, and no sequence data from Projapygoidea was available. The main aim of the present study was to investigate the phylogenetic position of Octostigmatidae, one of the three families of Projapygoidea, in Diplura and to test if Diplura are monophyletic. The complete 18S rRNA gene sequences of Octostigma sinensis (Projapygoidea: Octostigmatidae) from subtropical China, together with representative species of Campodeoidea and Japygoidea, and several species of Protura and Collembola were analyzed. The phylogenetic trees were obtained by different methods (neighbor-joining, maximum parsimony, and maximum likelihood) with a chelicerate species as outgroup. Our results suggested that Octostigma was closer to the genus Parajapyx (Japygoidea: Parajapygidae) than to the representative genus of Campodeidae (Campodeoidea). All phylogenetic trees supported the monophyly of Diplura.  相似文献   
84.
郑小艳  曹家树  滕元文 《园艺学报》2009,36(12):1827-1836
 近20年来, DNA序列已被广泛应用于植物各分类阶元的系统学研究中, 为解决长期有争议 的和亟待解决的系统进化问题提供了有力的证据。现以蔷薇科为例, 概述了应用DNA片段进行植物分子系统研究的现状, 详细剖析了应用DNA序列进行植物系统发育研究时常见的问题及其原因, 提出了对存在多倍化、杂交起源和快速分化等复杂进化史的植物类群进行系统学分析时选用DNA序列的策略和注意事项。  相似文献   
85.
蝇害已经成为危害规模化畜禽养殖的重要问题。文章回顾了防治蝇害的三代杀虫剂的发展过程和存在的问题 ;展望了作为新一代环境友好防治蝇害药物的昆虫生长调节剂的开发前景。  相似文献   
86.
Sequence comparisons and phylogenetic analysis of the 16S rRNA genes and the 16S/23S spacer regions of the phytoplasmas associated with Australian grapevine yellows, papaya dieback and Phormium yellow leaf diseases revealed minimal nucleotide differences between them resulting in the formation of a monophyletic group. Therefore, along with Australian grapevine yellows, the phytoplasmas associated with Phormium yellow leaf and papaya dieback should also be considered as Candidatus Phytoplasma australiense.  相似文献   
87.
ABSTRACT

1. The objectives of the current study were to investigate the mitochondrial genome and molecular phylogeny of Lueyang black-bone chicken, and provide molecule base to preserve and explore the specific chicken strain.

2. Based on sequencing and clustering, the complete mitochondrial DNA map and sequences of Lueyang black-bone chicken were revealed, and two phylogenetic trees of Lueyang black-bone chickens based on D-loop sequences and the mitochondrial genome were constructed.

3. The results showed that the complete mitochondrial genome of Lueyang black-bone chickens is 16,784bp in size, consisting of 22 transfer RNA genes, two ribosomal RNA genes, 13 protein-coding genes, and one non-coding control region. The base composition of the complete mtDNA sequence is 30.28% for A, 23.78% for T, 32.42% for C, 13.52% for G. Additionally, 10 haplotypes of D-loop sequences in 32 Lueyang black-bone chickens were detected, which were distributed into 4 clades (A, B, C and E).

4. It was concluded that genetic diversity is wide in Lueyang black-bone chickens, and this strain has multiple maternal origins from different regions in China and neighbouring regions.  相似文献   
88.
Leishmania infantum causes human and canine leishmaniosis. The parasite, transmitted by phlebotomine sand flies, infects species other than dogs and people, including wildlife, although their role as reservoirs of infection remains unknown for most species. Molecular typing of parasites to investigate genetic variability and evolutionary proximity can help understand transmission cycles and designing control strategies. We investigated Leishmania DNA variability in kinetoplast (kDNA) and internal transcribed spacer 2 (ITS2) sequences in asymptomatically infected wildlife (n = 58) and symptomatically and asymptomatically infected humans (n = 38) and dogs (n = 15) from south‐east Spain, using single nucleotide polymorphisms (SNPs) and in silico restriction fragment length polymorphism (RFLP) analyses. All ITS2 sequences (n = 76) displayed a 99%–100% nucleotide identity with a L. infantum reference sequence, except one with a 98% identity to a reference Leishmania panamensis sequence, from an Ecuadorian patient. No heterogeneity was recorded in the 73 L. infantum ITS2 sequences except for one SNP in a human parasite sequence. In contrast, kDNA analysis of 44 L. infantum sequences revealed 11 SNP genotypes (nucleotide variability up to 4.3%) and four RFLP genotypes including B, F and newly described S and T genotypes. Genotype frequency was significantly greater in symptomatic compared to asymptomatic individuals. Both methods similarly grouped parasites as predominantly or exclusively found in humans, in dogs, in wildlife or in all three of them. Accordingly, the phylogenetic analysis of kDNA sequences revealed three main clusters, two as a paraphyletic human parasites clade and a third including dogs, people and wildlife parasites. Results suggest that Leishmania infantum genetics is complex even in small geographical areas and that, probably, several independent transmission cycles take place simultaneously including some connecting animals and humans. Investigating these transmission networks may be useful in understanding the transmission dynamics, infection risk and therefore in planning L. infantum control strategies.  相似文献   
89.
Infections with influenza A viruses (IAV) are highly prevalent in swine populations, and stable cocirculation of at least three lineages has been well documented in European swine – till 2009. However, since the emergence of the human pandemic pdmH1N1 virus in 2009, which has been (re)introduced into individual swine herds worldwide, the situation has been changing. These variations in the respective IAV pools within pig populations are of major interest, and the zoonotic potential of putative emerging viruses needs to be evaluated. As data on recent IAV in swine from southern Germany were relatively sparse, the purpose of this study was to determine the major IAV subtypes actually present in this region. To this aim, from 2010 to 2013, 1417 nasal swabs or lung tissue samples from pigs with respiratory disease were screened for IAV genomes. Overall, in 130 holdings IAV genomes were detected by real‐time RT‐PCR targeting the matrix protein gene. For further analyses, several PCR protocols were adapted to quickly subtype between H1, pdmH1, H3, N1 and N2 sequences. Taken together, cocirculation of the three stable European lineages of IAV was confirmed for Bavaria. H1N1 sequences were identified in 59, whereas H1N2 genomes were only diagnosed in 14, and H3N2 in 9 of the holdings analysed. However, pdmH1 in combination with N1 was detected in 2010, 2012 and 2013 confirming a presence, albeit in low prevalence, likewise pdmH1N2 reassortant viruses. Interestingly, individual cases of coinfections with more than one subtype were diagnosed. Partial genome sequences were determined and phylogenetic analyses performed. Clearly other than in the human population classically circulating IAV have not been displaced by pdmH1N1 in Bavarian swine. However, some interesting viruses were detected. Further surveillance of these viruses in the Bavarian pig population will be of major importance, to monitor future developments.  相似文献   
90.
The study aimed to explore the phylogeny and genetic diversity of 3 hare species in Xinjiang by molecular genetics methods, define the relationship and taxonomy status, assess diversity level of Lepus in Xinjiang, and provide the basic data for conservation genetics of hares in Xinjiang and even in China. Three mitochondrial DNA genes, COI, ND4 and 16S rRNA, were used as molecular markers, and the sequences of 3 genes of 57 samples collected from 8 different regions (4 geographic groups) in Xinjiang were determined by PCR amplification and sequencing technology. After the sequences of COI, ND4 and 16S rRNA of each sample were revised and pooled together, data were analyzed with softwares such as MEGA 7, DNAsp 6, Arlequin 3.1 and MrBayes 3.2. A total of 43 haplotypes were detected from the combined sequences of 3 genes of 57 hare samples. Five distinct clades (A-E) and 3 clusters were clearly showed in phylogenetic tree and median-joining network (MJN). Furthermore, the genetic distance between 3 clusters reached the level of species (4.21%-9.09%). However, the genetic distance between hares from northern Xinjiang (Clade E) and those from central Xinjiang (Clade D) were not up to the level of species (≤2.26%) in the third cluster. The haplotype diversity (h) of Lepus yarkandensis, Lepus tibetanus pamirensis and Lepus tolai lehmanni were higher(0.979±0.014, 0.972±0.064 and 0.972±0.064, respectively), while the nucleotide diversity (π) of the L. t. lehmanni and L. t. centrasiaticus were higher (0.033±0.018 and 0.023±0.015, respectively). Based on comprehensive analysis of 3 genes of mitochondrion and reference with published research, it is suggested that hares from southwestern Pamir Plateau of Xinjiang should belong to L. t. pamirensis. Meanwhile,hares distributed in northern and central Xinjiang might be considered as L. t. lehmanni and L. t. centrasiaticus. Moreover, there is abundant genetic diversity in the 3 hare species in Xinjiang, and the obvious phylogeographic pattern is showed.  相似文献   
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