Search results for "phylogenetic"
showing 10 items of 1179 documents
Increased circulating and intrahepatic T-cell-specific chemokines in chronic hepatitis C: relationship with the type of virological response to pegin…
2004
Summary Aims : To determine the serum and intrahepatic levels of T-helper-1-associated chemokines in patients with chronic hepatitis C before, during and after peginterferon plus ribavirin combination therapy and to search for correlations with baseline characteristics of hepatitis C virus-related chronic liver disease and type of therapeutic response. Methods : Serum chemokine levels were determined by enzyme-linked immunosorbent assays and intrahepatic chemokine messenger RNA and protein levels were tested by ribonuclease protection assay and immunohistochemistry. Results : Serum and intrahepatic chemokine levels were elevated in all patients with chronic hepatitis C and showed a marked d…
The Chemokine Networks in Sponges: Potential Roles in Morphogenesis, Immunity and Stem Cell Formation
2003
Porifera (sponges) are now well accepted as the phylum which branched off first from the common ancestor of all metazoans, the Urmetazoa. The transition to the Metazoa became possible because during this phase, cell-cell as well as cell-matrix adhesion molecules evolved which allowed the formation of a colonial stage of animals. The next prerequisite for the evolution to the Urmetazoa was the establishment of an effective immune system which, flanked by apoptosis, allowed the formation of a first level of individuation.
Molecular evolution and complete genome sequences in forensic analysis: Neisseria gonorrhoeae in a transmission case
2019
Molecular epidemiology and phylogenetic analyses are frequently used in the investigation of viral transmission cases in forensic contexts. Here, we present the methods and results of the analysis of a bacterial transmission in an alleged child abuse case using complete genome sequences obtained by high-throughput sequencing (HTS) methods.
Phylogeny of long-tailed tits and allies inferred from mitochondrial and nuclear markers (Aves: Passeriformes, Aegithalidae)
2010
Abstract In this paper we provide a molecular phylogeny based on three mitochondrial and three nuclear markers for all long-tailed tit species of the genus Aegithalos including several doubtful subspecies (17 taxa) plus three close allies of SE Asian Leptopoecile and North American Psaltriparus . Genus Aegithalos is divided into three major clades, two of them showing only minor differentiation. Separation of two mitchondrial haploytpe clusters in the N Palearctic Long-tailed Tit, Ae. caudatus , was dated back to the Late Pleistocene, however, descendants from both lineages underwent a rapid post-Pleistocene range expansion and largely mixed over the entire distribution area. The Chinese po…
Biosystematic studies on the genus Polygonatum (Convallariaceae) IV. Molecular phylogenetic analysis based on restriction site mapping of the chlorop…
1997
Phylogenetic relationships of 14 species and one variety of the genus Polygonatum as well as three species of the genus Disporopsis and Heteropolygonatum roseolum were analyzed based on mapped restriction site variation in a PCR-amplified chloroplast genome region, trnK. In agreement with earlier taxonomic treatments it was found that Disporopsis and Heteropolygonatum should be distinguished from Polygonatum at generic level, and that P. sect. Polygonatum can be recognized as a monophyletic group. Earlier series concepts in P. sect. Polygonatum based on chromosome number and characteristics of staminal filaments are not supported by the molecular data. The molecular data suggest that satell…
Transition from Protozoa to Metazoa: An Experimental Approach
1998
Until recently, stromatolites were thought to be the oldest fossils on earth that were very abundant 2000 to 3000 Ma (million years) ago (Walter 1994). Recently, the biological origin of these fossils has been questioned (Walter 1996). The universal phylogenetic tree exhibits a tripartite division of the living world into Bacteria (“eubacterial”), Archaea (“archebacterial”), and Eucarya [“eukaryotic” (Woese 1987; Woese et al. 1991)]. Based on comparisons of amino acid (aa) sequence data from enzymes, it has been proposed that the common ancestor of prokaryotes and eukaryotes lived about 2000 Ma ago (Doolittle et al. 1996). Phylogenetic analysis of the 70kDa heat-shock proteins suggested tha…
Phylogenetic relationship of the green alga Nanochlorum eukaryotum deduced from its chloroplast rRNA sequences.
1995
The marine green coccoidal alga Nanochlorum eukaryotum (N.e.) is of small size with an average diameter of 1.5 microns. It is characterized by primitive-appearing biochemical and morphological properties, which are considerably different from those of other green algae. Thus, it has been proposed that N.e. may be an early developed algal form. To prove this hypothesis, DNA of N.e. was isolated by a phenol extraction procedure, and the chloroplast DNA separated by preparative CsCl density-gradient centrifugation. The kinetic complexity of the nuclear and of the chloroplast DNA was evaluated by reassociation kinetics to 3 x 10(7) bp and 9 x 10(4) bp, respectively. Several chloroplast genes, i…
Chromosome painting of the pygmy tree shrew shows that no derived cytogenetic traits link primates and scandentia.
2012
We hybridized human chromosome paints on metaphases of the pygmy tree shrew (<i>Tupaia minor</i>, Scandentia). The lack of the ancestral mammalian 4/8 association in both Primates and Scandentia was long considered a cytogenetic landmark that phylogenetically linked these mammalian orders. However, our results show that the association 4/8 is present in <i>Tupaia </i>along with not previously reported associations for 1/18 and 7/10. Altogether there are 11 syntenic associations of human chromosome segments in the pygmy tree shrew karyotype: 1/18, 2/21, 3/21, 4/8, 7/10, 7/16, 11/20, 12/22 (twice), 14/15 and 16/19. Our data remove any cytogenetic evidence that Scandent…
Eight million years of maintained heterozygosity in chromosome homologs of cercopithecine monkeys
2020
In the Cercopithecini ancestor two chromosomes, homologous to human chromosomes 20 and 21, fused to form the Cercopithecini specific 20/21 association. In some individuals from the genus Cercopithecus, this association was shown to be polymorphic for the position of the centromere, suggesting centromere repositioning events. We set out to test this hypothesis by defining the evolutionary history of the 20/21 association in four Cercopithecini species from three different genera. The marker order of the various 20/21 associations was established using molecular cytogenetic techniques, including an array of more than 100 BACs. We discovered that five different forms of the 20/21 association w…
Positive selection in development and growth rate regulation genes involved in species divergence of the genus Radix
2015
AbstractBackgroundLife history traits like developmental time, age and size at maturity are directly related to fitness in all organisms and play a major role in adaptive evolution and speciation processes. Comparative genomic or transcriptomic approaches to identify positively selected genes involved in species divergence can help to generate hypotheses on the driving forces behind speciation. Here we use a bottom-up approach to investigate this hypothesis by comparative analysis of orthologous transcripts of four closely related EuropeanRadixspecies.ResultsSnails of the genusRadixoccupy species specific distribution ranges with distinct climatic niches, indicating a potential for natural …