Search results for "PHYLOGENY"
showing 10 items of 1398 documents
Blattella germanica displays a large arsenal of antimicrobial peptide genes
2020
Defence systems against microbial pathogens are present in most living beings. The German cockroach Blattella germanica requires these systems to adapt to unhealthy environments with abundance of pathogenic microbes, in addition to potentially control its symbiotic systems. To handle this situation, four antimicrobial gene families (defensins, termicins, drosomycins and attacins) were expanded in its genome. Remarkably, a new gene family (blattellicins) emerged recently after duplication and fast evolution of an attacin gene, which is now encoding larger proteins with the presence of a long stretch of glutamines and glutamic acids. Phylogenetic reconstruction, within Blattellinae, suggests …
Inter- and intra-specific genomic divergence in Drosophila montana shows evidence for cold adaptation
2018
This work was supported by the Academy of Finland to AH (projects 132619 and 267244) and to MK (projects 268214 and 272927) and NERC (UK) funding to MGR (grants NE/E015255/1 and NE/J020818/1) and PhD studentship to DJP (NE/I528634/1). The genomes of species that are ecological specialists will likely contain signatures of genomic adaptation to their niche. However, distinguishing genes related to ecological specialism from other sources of selection and more random changes is a challenge. Here we describe the genome of Drosophila montana, which is the most extremely cold-adapted Drosophila species. We use branch tests to identify genes showing accelerated divergence in contrasts between col…
The effect of RNA substitution models on viroid and RNA virus phylogenies.
2018
Abstract Many viroids and RNA viruses have genomes that exhibit secondary structure, with paired nucleotides forming stems and loops. Such structures violate a key assumption of most methods of phylogenetic reconstruction, that sequence change is independent among sites. However, phylogenetic analyses of these transmissible agents rarely use evolutionary models that account for RNA secondary structure. Here, we assess the effect of using RNA-specific nucleotide substitution models on the phylogenetic inference of viroids and RNA viruses. We obtained data sets comprising full-genome nucleotide sequences from six viroid and ten single-stranded RNA virus species. For each alignment, we inferre…
Getting there and around: Host range oscillations during colonization of the Canary Islands by the parasitic nematode Spauligodon
2016
Episodes of expansion and isolation in geographic range over space and time, during which parasites have the opportunity to expand their host range, are linked to the development of host-parasite mosaic assemblages and parasite diversification. In this study, we investigated whether island colonization events lead to host range oscillations in a taxon of host-specific parasitic nematodes of the genus Spauligodon in the Canary Islands. We further investigated whether range oscillations also resulted in shifts in host breadth (i.e., specialization), as expected for parasites on islands. Parasite phylogeny and divergence time estimates were inferred from molecular data with Bayesian methods. H…
Molecular phylogeny and forms of photosynthesis in tribe Salsoleae (Chenopodiaceae).
2016
Evolution of C3–C4 intermediate and C4 lineages are resolved in Salsoleae (Chenopodiaceae), and a model for structural and biochemical changes for the evolution of the Salsoloid form of C4 is considered.
Sugar exchanges in arbuscular mycorrhiza: RiMST5 and RiMST6, two novel Rhizophagus irregularis monosaccharide transporters, are involved in both suga…
2016
SPE IPM INRA UB CT1; International audience; Arbuscular mycorrhizal (AM) fungi are associated with about 80% of land plants. AM fungi provide inorganic nutrients to plants and in return up to 20% of the plant-fixed CO2 is transferred to the fungal symbionts. Since AM fungi are obligate biotrophs, unraveling how sugars are provided to the fungus partner is a key for understanding the functioning of the symbiosis. In this study, we identified two new monosaccharide transporters from Rhizophagus irregularis (RiMST5 and RiMST6) that we characterized as functional high affinity monosaccharide transporters. RiMST6 was characterized as a glucose specific, high affinity H(+) co-transporter. We prov…
Expression properties exhibit correlated patterns with the fate of duplicated genes, their divergence, and transcriptional plasticity in Saccharomyco…
2017
Gene duplication is an important source of novelties and genome complexity. What genes are preserved as duplicated through long evolutionary times can shape the evolution of innovations. Identifying factors that influence gene duplicability is therefore an important aim in evolutionary biology. Here, we show that in the yeast Saccharomyces cerevisiae the levels of gene expression correlate with gene duplicability, its divergence, and transcriptional plasticity. Genes that were highly expressed before duplication are more likely to be preserved as duplicates for longer evolutionary times and wider phylogenetic ranges than genes that were lowly expressed. Duplicates with higher expression lev…
An exhaustive phylogeny of the combtooth blenny genus Salaria (Pisces, Blenniidae) shows introgressive hybridization and lack of reciprocal mtDNA mon…
2019
A comprehensive phylogeny of the genus Salaria based on mitochondrial and nuclear markers grouped the extant species of the genus in well-characterised marine and freshwater clades, thus rejecting the hypothesis of a polytypic origin of the freshwater Salaria populations and supporting the occurrence of a single invasion event of the inland waters by the genus. Based on both mitochondrial and nuclear DNA datasets, the Salaria species of the freshwater clade proved to be vicariant taxa originating from a common ancestor which could possibly spread throughout the circum-Mediterranean inland waters during the late Miocene Messinian salinity crisis, then experiencing a process of allopatric dif…
The evolution of colour pattern complexity: selection for conspicuousness favours contrasting within-body colour combinations in lizards.
2015
Many animals display complex colour patterns that comprise several adjacent, often contrasting colour patches. Combining patches of complementary colours increases the overall conspicuousness of the complex pattern, enhancing signal detection. Therefore, selection for conspicuousness may act not only on the design of single colour patches, but also on their combination. Contrasting long- and short-wavelength colour patches are located on the ventral and lateral surfaces of many lacertid lizards. As the combination of long- and short-wavelength-based colours generates local chromatic contrast, we hypothesized that selection may favour the co-occurrence of lateral and ventral contrasting patc…
Topological congruence between phylogenies of Anacanthorus spp. (Monogenea: Dactylogyridae) and their Characiformes (Actinopterygii) hosts: A case of…
2017
Cophylogenetic studies aim at testing specific hypotheses to understand the nature of coevolving associations between sets of organisms, such as host and parasites. Monogeneans and their hosts provide and interesting platform for these studies due to their high host specificity. In this context, the objective of the present study was to establish whether the relationship between Anacanthorus spp. with their hosts from the upper Paraná River and its tributaries can be explained by means of cospeciation processes. Nine fish species and 14 monogenean species, most of them host specific, were studied. Partial DNA sequences of the genes RAG1, 16S and COI of the fish hosts and of the genes ITS2, …