Accueil > Communication > Actualités scientifiques > Publications scientifiques

Publications scientifiques RSS des Publications scientifiques

Page(s) : < | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | ... | 304 |

19 octobre 2018

Correlated Evolution of Two Copulatory Organs via a Single cis-Regulatory Nucleotide Change [Current Biology]

Keywords : pleiotropy, cis-regulatory, sensory organ, Drosophila, copulation, genitalia, hypandrium, sex comb, microevolution, scute, Abd-B

Diverse traits often covary between species. The possibility that a single mutation could contribute to the evolution of several characters between species is rarely investigated as relatively few cases are dissected at the nucleotide level. Drosophila santomea has evolved additional sex comb sensory teeth on its legs and has lost two sensory bristles on its genitalia. We present evidence that a single nucleotide substitution in an enhancer of the scute gene contributes to both changes. The mutation alters a binding site for the Hox protein Abdominal-B in the developing genitalia, leading to bristle loss, and for another factor in the developing leg, leading to bristle gain. Our study suggests that morphological evolution between species can occur through a single nucleotide change affecting several sexually dimorphic traits.

Lire la suite

19 octobre 2018

Biodiversity increases and decreases ecosystem stability [Nature]

Keywords : biodiversity, community ecology

Losses and gains in species diversity affect ecological stability and the sustainability of ecosystem functions and services. Experiments and models have revealed positive, negative and no effects of diversity on individual components of stability, such as temporal variability, resistance and resilience. How these stability components covary remains poorly understood. Similarly, the effects of diversity on overall ecosystem stability, which is conceptually akin to ecosystem multifunctionality, remain unknown. Here we studied communities of aquatic ciliates to understand how temporal variability, resistance and overall ecosystem stability responded to diversity (that is, species richness) in a large experiment involving 690 micro-ecosystems sampled 19 times over 40 days, resulting in 12,939 samplings.Species richness increased temporal stability but decreased resistance to warming. Thus, two stability components covaried negatively along the diversity gradient.(...)

Lire la suite

19 octobre 2018

Density-dependent adult recruitment in a low-density tropical tree [PNAS]

Keywords : Bayesian state–space, density dependence, Janzen Connell, population dynamics, remote sensing

The Janzen–Connell hypothesis is a well-known explanation for why tropical forests have large numbers of tree species. A fundamental prediction of the hypothesis is that the probability of adult recruitment is less in regions of high conspecific adult density, a pattern mediated by density-dependent mortality in juvenile life stages. Although there is strong evidence in many tree species that seeds, seedlings, and saplings suffer conspecific density-dependent mortality, no study has shown that adult tree recruitment is negatively density dependent. Density-dependent adult recruitment is necessary for the Janzen–Connell mechanism to regulate tree populations. Here, we report density-dependent adult recruitment in the population of Handroanthus guayacan, a wind-dispersed Neotropical canopy tree species. We use data from high-resolution remote sensing to track individual trees with proven capacity to flower in a lowland moist forest landscape in Panama and analyze these data in a Bayesian framework similar to capture–recapture analysis.(...)

Lire la suite

19 octobre 2018

Genome and evolution of the arbuscular mycorrhizal fungus Diversispora epigaea (formerly Glomus versiforme) and its bacterial endosymbionts [New Phytologist]

Keywords : arbuscular mycorrhizal (AM) fungi, Diversispora epigaea, endobacteria, endosymbiosis, fungal evolution, fungal genomics, Glomus versiforme, Mollicutes/Mycoplasma‐related endobacteria (MRE)

Arbuscular mycorrhizal (AM) fungi form endosymbioses with most plants, and they themselves are hosts for Mollicutes/Mycoplasma‐related endobacteria (MRE). Despite their significance, genomic information for AM fungi and their MRE are relatively sparse, which hinders our understanding of their biology and evolution.
We assembled the genomes of the AM fungus Diversispora epigaea (formerly Glomus versiforme) and its MRE and performed comparative genomics and evolutionary analyses.(...)

Lire la suite

19 octobre 2018

Variation in ectomycorrhizal fungal communities associated with Silver linden (Tilia tomentosa) within and across urban areas [FEMS Microbiology Ecology]

Keywords : next generation sequencing, heavy metal pollution, urbanization, EcM, ectomycorrhiza, environmental drivers

Trees in urban areas face harsh environmental conditions. Ectomycorrhizal fungi (EcM) form a symbiosis with many tree species and provide a range of benefits to their host through their extraradical hyphal network. Although our understanding of the environmental drivers and large scale geographical variation of EcM communities in natural ecosystems is growing, our knowledge of EcM communities within and across urban areas is still limited. Here we characterized EcM communities using Illumina miseq sequencing on 175 root samples of the urban tree Tilia tomentosa from three European cities, namely Leuven (Belgium), Strasbourg (France) and Porto (Portugal).(...)

Lire la suite

Page(s) : < | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | ... | 304 |