5,565 research outputs found
Heterogeneity in Ty1-copia group of retroelements in chickpea (Cicer arietinum) genome
No full textRetrotransposons constitute a major fraction of plant genomes and these elements may have played a significant role in evolution and sequence organization of genomes. In order to access the diversity of Ty1-copia group of retroelements, reverse transcriptase (RT) sequences were amplified from chickpea genome, using the primers derived from two conserved domains of RT region. Thirty-six RT regions from independent amplicons were cloned and sequenced. On the basis of homology of deduced amino acids, the RT sequences could be grouped into three major families. The intra-family divergence at amino acid level ranges from 2 to 19%. Though intra-family RT sequences were conserved but no two sequences were identical. The results indicate a high degree of heterogeneity among the Ty1-copia group of retroelements from chickpea. It was possible to isolate RT specific sequences from RNA isolated from stressed seedlings, indicating that some of the retroelements may be functional under certain stress conditions
LTR-retrotransposons in R. exoculata and other crustaceans
No full textTransposable elements are major constituents of eukaryote genomes and have a great impact on genome structure and stability. They can contribute to the genetic diversity and evolution of organisms. Knowledge of their distribution among several genomes is an essential condition to study their dynamics and to better understand their role in species evolution. LTR-retrotransposons have been reported in many diverse eukaryote species, describing a ubiquitous distribution. Given their abundance, diversity and their extended ranges in C-values, environment and life styles, crustaceans are a great taxon to investigate the genomic component of adaptation and its possible relationships with TEs. However, crustaceans have been greatly underrepresented in transposable element studies. Using both degenerate PCR and in silico approaches, we have identified 35 Copia and 46 Gypsy families in 15 and 18 crustacean species, respectively. In particular, we characterized several full-length elements from the shrimp Rimicaris exoculata that is listed as a model organism from hydrothermal vents. Phylogenic analyses show that Copia and Gypsy retrotransposons likely present two opposite dynamics within crustaceans. The Gypsy elements appear relatively frequent and diverse whereas Copia are much more homogeneous, as 29 of them belong to the single GalEa clade, and species- or lineage-dependent. Our results also support the hypothesis of the Copia retrotransposon scarcity in metazoans compared to Gypsy elements. In such a context, the GalEa-like elements present an outstanding wide distribution among eukaryotes, from fishes to red algae, and can be even highly predominant within a large taxon, such as Malacostraca. Their distribution among crustaceans suggests a dynamics that follows a "domino days spreading" branching process in which successive amplifications may interact positively
A comparative investigation of nuclear DNA content and its phenotypic impacts in Silene marizii and S. latifolia
No full textConsiderable variation exists both within and between species in nuclear DNA content. Despite there being no obvious functional role for much of this DNA, many studies have reported phenotypic correlations with genome size at various taxonomic levels. This suggests that DNA plays a functional role beyond the traditionally understood mechanisms. One such example of a phenotypic correlation with DNA content is present in the genus Silene, where a negative correlation between DNA content and flower size exists within and between species. This relationship is consistent with the direction of sexual dimorphism in DNA content (caused by heteromorphic sex-chromosomes) and flower size in the most studied species in the genus: S. latifolia.
This thesis takes a comparative approach between two closely related species in the genus (S. latifolia and S. marizii), which differ markedly in their nuclear DNA content, in order to investigate the nature and phenotypic impacts of variation in DNA content.
A phenotypic survey from a number of S. marizii populations reveals that the pattern of DNA content variation in this species is very different to that in S. latifolia. In particular, phenotypic correlations with DNA content appear be much weaker, whilst sexual dimorphism in DNA content, when present, appears to occur in either direction. A survey of interspecific hybrids suggests that this may be due to an enlarged S. marizii X-chromosome and that DNA content in hybrids may be biased with regard to their parents. Repetitive elements may be significant constituents of plant genomes. A study of Ty1-copia class retrotransposons in the two species reveals that they are present as a large and highly heterogeneous population. Phylogenetic analysis of these elements suggests a substantial degree of genetic isolation between the two species. Finally, an assessment of the flow-cytometric method, used to estimate DNA content, reveals substantial error associated with the method, but only limited evidence for stoichiometric effects
Erasmi libros de duplici copia. 2, De duplici copia verborum ac rerum commentarius / non minus utilis quam eruditus M. Veltkirchii,...
No full text[De duplici copia verborum ac rerum (latin)]Collection : French books before 1601 ; 61.1Collection : French books before 1601 ; 61.
Continuous infusion idarubicin and intravenous busulphan as conditioning regimen to autologous stem cell transplantation for patients with acute myeloid leukaemia
No full textErasmi libros de duplici copia. 3, De copia verborum Erasmi Roterodami : quam ratio varandiae orationis exemplis atque, explanationibus paulo apertioribus traditur
No full text[De duplici copia verborum ac rerum (latin)]Collection : French books before 1601 ; 61.1Collection : French books before 1601 ; 61.
FLT3 mutations have no prognostic impact in elderly patients with acute myeloid leukemia and normal karyotype.
No full textTreatment of chronic myeloid leukemia in the blastic phase with fludarabine, cytosine arabinoside and G-CSF (FLAG)
No full textComplete remission of refractory anemia following a single high dose of cyclophosphamide.
No full textImmunophenotypic analysis enables the correct prediction of t(8;21) in acute myeloid leukaemia.
No full text- …
