Search results for "phylogenetic"
showing 10 items of 1179 documents
Les Gonorynchiformes fossiles : distribution et diversité.
2007
8 pages; Longtemps placés dans les clupéiformes, les Gonorynchiformes ont rejoint les Ostariophysi au sein desquels ils représentent le groupe-frère des Otophysi. La monophylie du groupe est maintenant bien établie tant par les données morphologiques que moléculaires. De nos jours, quatre familles sont représentées par sept genres (dont cinq d'eau douce) et 35 espèces (dont 28 d'eau douce). Les Gonorynchiformes fossiles sont connus depuis le Crétacé basal (soit 145-140 millions d'années) jusqu'au Miocène basal (soit 23,5-20 millions d'années), et plusieurs taxons ont de grandes extensions temporelles. Ils sont représentés par environ 18 genres et 34 espèces. Avec moins de 50 localités fossi…
A mathematical method for determining genome divergence and species delineation using AFLP.
2002
The delineation of bacterial species is presently achieved using direct DNA-DNA relatedness studies of whole genomes. It would be helpful to obtain the same genomically based delineation by indirect methods, provided that descriptions of individual genome composition of bacterial genomes are obtained and included in species descriptions. The amplified fragment length polymorphism (AFLP) technique could provide the necessary data if the nucleotides involved in restriction and amplification are fundamental to the description of genomic divergences. Firstly, in order to verify that AFLP analysis permits a realistic exploration of bacterial genome composition, the strong correspondence between …
A multigene phylogenetic study of Tuber aestivum/uncinatum
2011
International audience; Tuber aestivum and Tuber uncinatum share a complicated common history from a taxonomic point of view. Indeed, different previous studies have shown contradictory conclusions. For some authors, Tuber aestivum and Tuber uncinatum are one species and for others, they are two different species. In those studies, few phylogenetic markers have been used, mainly the ITS marker. However, it has become the standard in phylogenetic studies to combine several genes to obtain a more robust phylogenetic representation. In our study, we used 9 molecular markers and sampled fruiting bodies from different European populations including 14 Tuber “aestivum” types and 14 “uncinatum” ty…
Crustacés amphipodes de surface (Gammares d'eau douce)
2012
EA MERS CT3; National audience; L’ouvrage de Piscart & Bollache présente une clef de détermination actualisée des amphipodes de surface de la France métropolitaine. Les espèces natives et invasives sont décrites, avec une carte de la répartition de chaque espèce. L’ouvrage est agrémenté d’une partie décrivant l’écologie des amphipodes, leur comportement et leurs pathogènes les plus fréquemment rencontrés.
Two new species of the genus Ochroconis, O. lascauxensis and O. anomala isolated from black stains in Lascaux Cave, France
2012
In the year 2001, some conspicuous black stains appeared on the walls of Lascaux Cave in France, which progressively disseminated throughout the cave. These black stains were so evident by 2007 that they have become one of the cave's major problems. In a mycological study of the black stains, Ochroconis strains were abundant among the isolates and constituted the major group of melanised fungi. Two new species of the genus Ochroconis, O. lascauxensis and O. anomala, were isolated and described. The description is based on the morphology of the fungi and the phylogenetic relationships of two of its gene regions internal transcribed spacer (ITS) and RNA polymerase II subunit B (RPB2). In addi…
Linking species interactions with phylogenetic and functional distance in European bird assemblages at broad spatial scales
2017
Aim: Understanding the relative contribution of different species interactions in shaping community assembly has been a pivotal aim in community ecology. Biotic interactions are acknowledged to be important at local scales, although their signal is assumed to weaken over longer distances. We examine the relationship between positive, neutral and negative pairwise bird abundance distributions and the phylogenetic and functional distance between these pairs after first controlling for habitat associations. Location: France and Finland. Time period: 1984 to 2011 (Finland), 2001 to 2012 (France). Major Taxa studied: Birds. Methods: We used results from French and Finnish land bird monitoring pr…
PCR survey ofXenoturbella bockiHox genes
2007
Xenoturbella bocki has recently been identified as one of the most basal deuterostomes, although an even more basal phylogenetic position cannot be ruled out. Here we report on a polymerase chain reaction survey of partial Hox homeobox sequences of X. bocki. Surprisingly, we did not find evidence for more than five Hox genes, one clear labial/PG1 ortholog, one posterior gene most similar to the PG9/10 genes of Ambulacraria, and three central group genes whose precise assignment to a specific paralog group remains open. We furthermore report on a re-evaluation of the available published evidence of Hox genes in other basal deuterostomes.
Number, identity, and sequence of the Drosophila head segments as revealed by neural elements and their deletion patterns in mutants.
1994
The development of the insect head tagma involves massive rearrangements and secondary fusions of segment anlagen during embryogenesis. Due to the lack of reliable morphological markers, the number, identity, and sequence of the head segments, particularly in the pregnathal region, are still a matter of ongoing debates. We examined the complex array of internal structures of the embryonic Drosophila melanogaster head such as the sensory structures and nerves of the peripheral and stomatogastric nervous systems, and we used embryonic head mutations causing a lack of overlapping segment anlagen to unravel the segmental identity and the sequence of the neural elements. Our results provide evid…
Globin genes are present in Ciona intestinalis.
2003
The key position of the Ciona intestinalis basal to the vertebrate phylogenetic tree brings up the question of which respiratory proteins are used by the tunicate to facilitate oxygen transport and storage. The publication of the Ciona draft genome sequence suggests that globin genes are completely missing and that-like some molluscs and arthropods-the sea squirt uses hemocyanin instead of hemoglobin for respiration. However, we report here the presence and expression of at least four distinct globin gene/protein sequences in Ciona. This finding is in agreement with the ancestral phylogeny of the vertebrate globins. Moreover, it seems likely that the Ciona hemocyanin-like sequences have enz…
Traits and phylogenies modulate the environmental responses of wood-inhabiting fungal communities across spatial scales
2022
Identifying the spatial scales at which community assembly processes operate is fundamental for gaining a mechanistic understanding of the drivers shaping ecological communities. In this study, we examined whether and how traits and phylogenetic relationships structure fungal community assembly across spatial scales. We applied joint species distribution modelling to a European-scale dataset on 215 wood-inhabiting fungal species, which includes data on traits, phylogeny and environmental variables measured at the local (log-level) and regional (site-level) scales. At the local scale, wood-inhabiting fungal communities were mostly structured by deadwood decay stage, and the trait and phyloge…