Search results for "phylogenetic tree"
showing 10 items of 557 documents
Lactobacillus rennini sp. nov., isolated from rennin and associated with cheese spoilage.
2006
Two bacterial strains, DSM 20253T and DSM 20254, isolated from rennin and regarded as causing cheese spoilage, were deposited in the DSMZ as Lactobacillus sp. by J. Stadhouders. The strains show 99·9 % 16S rRNA gene sequence similarity and have less than 94·3 % similarity with any other species of the genus. Lactobacillus coryniformis is their closest phylogenetic neighbour. DNA–DNA hybridization experiments confirmed that the two strains are members of the same species with separate status within the genus Lactobacillus. The strains are homofermentative lactic acid bacteria and can be phenotypically and genotypically distinguished from their closest relatives. 16S rRNA gene-targeted specif…
Recombination in Hepatitis C Virus
2011
Hepatitis C virus (HCV) is a Flavivirus with a positive-sense, single-stranded RNA genome of about 9,600 nucleotides. It is a major cause of liver disease, infecting almost 200 million people all over the world. Similarly to most RNA viruses, HCV displays very high levels of genetic diversity which have been used to differentiate six major genotypes and about 80 subtypes. Although the different genotypes and subtypes share basic biological and pathogenic features they differ in clinical outcomes, response to treatment and epidemiology. The first HCV recombinant strain, in which different genome segments derived from parentals of different genotypes, was described in St. Petersburg (Russia) …
A new subtype of hepatitis C virus genotype 1: complete genome and phylogenetic relationships of an Equatorial Guinea isolate.
2006
Hepatitis C virus (HCV) is the leading cause of chronic liver disease and is associated with hepatocellular carcinoma. However, there have been few studies on the distribution and genetic diversity of HCV isolates in non-developed countries. Here, the complete genome sequence of an HCV genotype 1 isolate from Equatorial Guinea is reported, the first complete HCV-1 genome of African origin. Phylogenetic analysis revealed that this sequence always grouped with sequences of genotype 1, but did not group clearly with any subtype described so far. An analysis of partial NS5B gene sequences with additional sequences of African origin also failed to find close similarities between the new sequenc…
Genome-Wide SNP-Genotyping Array to Study the Evolution of the Human Pathogen Vibrio vulnificus Biotype 3
2014
Vibrio vulnificus is an aquatic bacterium and an important human pathogen. Strains Of V. vulnificus are classified into three different biotypes. The newly emerged biotype 3 has been found to be clonal and restricted to Israel. In the family Vibrionaceae , horizontal gene transfer is the main mechanism responsible for the emergence of new pathogen groups. To better understand the evolution of the bacterium, and in particular to trace the evolution of biotype 3, we performed genome-wide SNP genotyping of 254 clinical and environmental V. vulnificus isolates with worldwide distribution recovered over a 30-year period, representing all phylogeny groups. A custom single-nucleotide polymorphism …
The phylogenetic relationships and evolution of the Canarian laurel forest endemicIxanthus viscosus (Aiton) Griseb. (Gentianaceae): Evidence frommatK…
1999
The phylogenetic relationships of the Canarian laurel forest endemicIxanthus viscosus (Aiton) Griseb. (Gentianaceae) are investigated through a cladistic analysis of sequence variation of parts of the chloroplast genematK and the ITS region of nuclear ribosomal DNA. The floral anatomical and morphological characteristics ofIxanthus based on paraffin sections and SEM studies are also discussed. In the molecular analysesIxanthus is part of a clade of mostly temperate Erythraeinae and Chironiinae sensu Gilg, in which it is sister to the mostly Mediterranean annualBlackstonia. This relationship is supported by farreaching similarities in flower morphology and anatomy, and the shared possession …
Genetic diversity and relationships among Italian and foreign almond germplasm as revealed by microsatellite markers
2013
Abstract Italian germplasm is characterized by a wide diversity rapidly developed determining a massive genetic pool of cultivars in several growing areas. On the whole, regions of southern Italy, and in particular Sicily, were considered as one of the main trade routes along which almond was spread throughout the shores of the Mediterranean Sea. In this work, 9 SSR markers have been used to analyze 113 almond cultivars and accessions coming from ex-situ conservation, including most of almond genotypes spread in Sicily and Apulia and foreign cultivars from Mediterranean, American and Australian areas in order to determine the level of genetic diversity within Italian genotypes and elucidate…
Centennial olive trees as a reservoir of genetic diversity
2011
†Background and Aims Genetic characterization and phylogenetic analysis of the oldest trees could be a powerful tool both for germplasm collection and for understanding the earliest origins of clonally propagated fruit crops. The olive tree (Olea europaea L.) is a suitable model to study the origin of cultivars due to its long lifespan, resulting in the existence of both centennial and millennial trees across the Mediterranean Basin. †Methods The genetic identity and diversity as well as the phylogenetic relationships among the oldest wild and cultivated olives of southern Spain were evaluated by analysing simple sequence repeat markers. Samples from both the canopy and the roots of each tr…
Evolutionary morphology in shape and size of haptoral anchors in 14 Ligophorus spp. (Monogenea: Dactylogyridae).
2017
The search for phylogenetic signal in morphological traits using geometric morphometrics represents a powerful approach to estimate the relative weights of convergence and shared evolutionary history in shaping organismal form. We assessed phylogenetic signal in the form of ventral and dorsal haptoral anchors of 14 species of Ligophorus occurring on grey mullets (Osteichthyes: Mugilidae) from the Mediterranean, the Black Sea and the Sea of Azov. The phylogenetic relationships among these species were mapped onto the morphospaces of shape and size of dorsal and ventral anchors and two different tests were applied to establish whether the spatial positions in the morphospace were dictated by …
First record of Temnosewellia minor (Platyhelminthes, Temnocephalidae) in Sicily, with a plea for a re-examination of the identity of the publicly av…
2021
Author(s): Vecchioni, Luca; Chirco, Pietro; Bazan, Giuseppe; Marrone, Federico; Arizza, Vincenzo; Arculeo, Marco | Abstract: Ectosymbiotic temnocephalan flatworms belonging to the genus Temnosewellia Damborenea and Cannon, 2001 were collected on Cherax destructor Clark, 1936 in an aquaculture farm in Sicily, Italy. This represents the first record of a temnocephalan species for the fauna of the island. Morphological and molecular identification of the collected specimens proved that they belong to the allochthonous species Temnosewellia minor Haswell, 1888, which was introduced along with crayfishes bred in aquaculture farms. The phylogenetic analyses carried out for the molecular identific…
Organ xenografting between rodents: an evolutionary perspective
1994
Rejection times of heart xenografts in several donor-recipient combinations including the guinea pig, rat, hamster, and mouse are examined in light of the paleontological history of rodents and the resulting phylogenetic distances between taxa. This multidisciplinary review at the molecular, chromosomal and morphological levels suggests that xenograft rejection time is inversely proportional to the time divergence or phylogenetic distance, and that the binomial terminology concordant/discordant does not reflect the amplitude of phylogenetic distances.