Phylogeographical structure of vairone Telestes muticellus (Teleostei, Cyprinidae) within three European peri-Mediterranean districts

The phylogeographical pattern of vairone ( Telestes muticellus ) populations was assessed to test the biogeographical distinction of three peri-Mediterranean ichthyogeographical districts: Padano-Venetian (PV), Tuscano-Latium (TL) and southern France (SF), evaluating the role of Alpine and Apennine barriers in shaping distinct evolutionary lineages. A fragment of mitochondrial DNA (mtDNA) cytochrome b (cyt b ) was sequenced in 153 specimens from 14 north-western Italian populations, collected in 10 tributaries of Po River and in four rivers on the Tyrrhenian slope of Ligury, and 32 haplotypes were identified. The phylogenetic analyses confirmed the presence of two distinct clades, an 'Italian clade' ( T. muticellus ) and a 'French clade' ( T. souffia ), showing an average genetic distance of 12.9% (± 1.3 SD) and allopatric distribution. The Nested Clade Analysis (NCA) and the Analysis of Molecular Variance ( amova ) revealed an isolated gene pool in eastern basins on the Tyrrhenian slope of Ligury. The phylogeographical findings suggest: (i) the lack of permeability of Alpine barrier towards the dispersion across Italian and French hydrographical systems; and (ii) partial permeability of Mediterranean Alps and Apennines through river captures crossing lower watersheds.     

Protein-based phylogenies support a chimeric origin for the eukaryotic genome

The phylogenetic position of the archaebacteria and the place of eukaryotes in the history of life remain a question of debate. Recent studies based on some protein-sequence data have obtained unusual phylogenies for these organisms. We therefore collected the protein sequences that were available with representatives from each of the major forms of life: the gram-negative bacteria, gram-positive bacteria, archaebacteria, and eukaryotes. Monophyletic, unrooted phylogenies based on these sequence data show that seven of 24 proteins yield a significant gram-positive-archaebacteria clade/gram-negative- eukaryotic clade. The phylogenies for these seven proteins cannot be explained by the traditional three-way split of the eukaryotes, archaebacteria, and eubacteria. Nine of the 24 proteins yield the traditional gram-positive-gram-negative clade/archaebacteria-eukaryotic clade. The remaining eight proteins give phylogenies that cannot be statistically distinguished. These results support the hypothesis of a chimeric origin for the eukaryotic cell nucleus formed from the fusion of an archaebacteria and a gram-negative bacteria.      

The mosaic nature of the eukaryotic nucleus

The phylogenies for each of the protein-coding genes from the Methanococcus jannaschii genome were surveyed to determine the history of the major groups of life. For each gene, homologous sequences from other archaea, eucarya, and Gram-positive and Gram-negative bacteria were collected and aligned, and a phylogeny was reconstructed with a maximum-likelihood algorithm. The majority of significant phylogenies favor the eucarya and the archaca as sister groups. A smaller, but still substantial, portion of these significant phylogenies favor an eucarya/Gram-negative clade. These results indicate that support for the early history of life is not unequivocal. A chimeric origin of eukaryotes or an ancient, massive horizontal transfer of genes from Gram-negative bacteria to eucarya can explain many of the observed phylogenies.      

Lipofection of Purified Adeno-Associated Virus Rep68 Protein: toward a Chromosome-Targeting Nonviral Particle

Adeno-associated virus (AAV) integrates very efficiently into a specific site (AAVS1) of human chromosome 19. Two elements of the AAV genome are sufficient: the inverted terminal repeats (ITRs) and the Rep78 or Rep68 protein. The incorporation of the AAV integration machinery in nonviral delivery systems is of great interest for gene therapy. We demonstrate that purified recombinant Rep68 protein is functionally active when directly delivered into human cells by using the polycationic liposome Lipofectamine, promoting the rescue-replication of a codelivered ITR-flanked cassette in adenovirus-infected cells and its site-specific integration in noninfected cells. The sequencing of cloned virus-host DNA junctions confirmed that lipofected Rep68 protein triggers site-specific integration at the same sites in chromosome 19 already characterized in cells latently infected with AAV.