Search results for "Phenotype"
showing 10 items of 1875 documents
Does trait-based joint species distribution modelling reveal the signature of competition in stream macroinvertebrate communities?
2021
1. The occupancy and abundance of species are jointly driven by local factors, such as environmental characteristics and biotic interactions, and regional‐scale factors, such as dispersal and climate. Recently, it has been shown that biotic interactions shape species occupancies and abundances beyond local extents. However, for small ectothermic animals, particularly for those occurring in freshwater environments, the importance of biotic interactions remains understudied. Species‐to‐species associations from joint species distribution models (i.e. species associations while controlling for environmental characteristics) are increasingly used to draw hypotheses of which species possibly sho…
When less means more: evolutionary and developmental hypotheses in rodent molars.
2012
10 pages; International audience; Tooth number in rodents is an example of reduction in evolution. All rodents have a toothless diastema lacking canine and most premolars present in most other mammals. Whereas some rodent lineages retained one premolar (p4), many others lost it during evolution. Recently, an 'inhibitory cascade' developmental model (IC) has been used to predict how the first molar (m1) influences the number and relative sizes of the following distal molars (m2 and m3). The model does not, however, consider the presence of premolars, and here we examine whether the premolar could influence and constrain molar proportions during development and evolution. By investigating a l…
Adaptation of turnip mosaic potyvirus to a specific niche reduces its genetic and environmental robustness
2020
Robustness is the preservation of the phenotype in the face of genetic and environmental perturbations. It has been argued that robustness must be an essential fitness component of RNA viruses owed to their small and compacted genomes, high mutation rates and living in ever-changing environmental conditions. Given that genetic robustness might hamper possible beneficial mutations, it has been suggested that genetic robustness can only evolve as a side-effect of the evolution of robustness mechanisms specific to cope with environmental perturbations, a theory known as plastogenetic congruence. However, empirical evidences from different viral systems are contradictory. To test how adaptation…
DNA polymorphism at the FRIGIDA gene in Arabidopsis thaliana : extensive nonsynonymous variation is consistent with local selection for flowering time
2002
FRIGIDA (FRI) is a major gene involved in the regulation of flowering time in Arabidopsis thaliana. Nucleotide variation at this gene was investigated by sequencing 25 field ecotypes collected from western Europe. Genetic diversity at FRI was characterized by a high number of haplotypes and an excess of low-frequency polymorphisms. A large excess of intraspecific nonsynonymous variation associated with low synonymous variation was detected along the first exon in the FRI gene. In contrast, no excess of nonsynonymous divergence was detected between A. thaliana and A. lyrata. The Tajima and McDonald and Kreitman tests, however, suggested that this gene has evolved in a nonneutral fashion. Non…
Time to split Salvia s.l. (Lamiaceae) - New insights from Old World Salvia phylogeny.
2017
Abstract Aims Salvia L. is widely known as the largest genus in the mint family. A morphological modification of the androecium (lever-like stamens) was used to support this genus. However, molecular data revealed that Salvia is polyphyletic. Since phylogenetic studies largely underrepresented Old World Salvia species, we filled this gap and combined new data with existing sequences. The aim of our study was the identification of well-supported clades that provide the basis for evolutionary and taxonomic conclusions. Methods We included ITS data (internal transcribed spacer) from 220 Salvia species, 86 of which were sequenced for the first time. Additionally, the highly variable plastid mar…
Selection for reproduction under short photoperiods changes diapause-associated traits and induces widespread genomic divergence.
2019
The work has been supported by the Academyof Finland to A.H. (project 267244) and Natural Environment Research Council (NERC) funding (NE/J020818/1 to M.G.R.; NE/L501852/1 to R.A.W.W.). The incidence of reproductive diapause is a critical aspect of life history in overwintering insects from temperate regions. Much has been learned about the timing, physiology and genetics of diapause in a range of insects, but how the multiple changes involved in this and other photoperiodically regulated traits are inter-related is not well understood. We performed quasinatural selection on reproduction under short photoperiods in a northern fly species, Drosophila montana, to trace the effects of photoper…
Interactions between dark septate endophytes, ectomycorrhizal fungi and root pathogens in vitro
2019
ABSTRACT Dark septate endophytes (DSEs) are widely distributed worldwide and can promote plant growth. Therefore, they are considered potentially important plant allies, especially in stressful environments. Previous studies have reported that DSEs cohabit roots with other microorganisms such as ectomycorrhizal (ECM), endophytic and pathogenic fungi/oomycetes. However, interactions between different DSE species have not yet been reported, and studies on the interactions between DSEs and other fungi are scarce. Using a simple and reproducible pairwise growth assay in vitro, we studied the synergistic/antagonistic interactions between eight DSEs, two ECM fungi and three root pathogens. Most o…
Distinct protoconchs recognised in three of the larger Mediterranean Cerithium species (Caenogastropoda: Cerithiidae)
2017
The gastropod genus Cerithium includes several polymorphic species which are hardly distinguishable using a morphological approach based on teleoconch characters. Here we show that protoconch characters can be reliably used to identify the larger Mediterranean species (Cerithium alucastrum, C. repandum and C. vulgatum), and to assess their intraspecific variability. Based on a large amount of morphological data, we show that a multispiral, strongly sculptured protoconch (traditionally associated with C. vulgatum) is found in C. alucastrum. This species originated in the Pliocene. A multispiral, weakly sculptured protoconch, not observed previously, is reported for C. vulgatum. A paucispiral…
Large Spatial Scale of the Phenotype-Environment Color Matching in Two Cryptic Species of African Desert Jerboas (Dipodidae: Jaculus)
2014
We tested the camouflage hypothesis, or the linkage between animal (Saharan rodent) and habitat coloration, on the largest geographical scale yet conducted. We aimed to determine whether phenotypic variation is explained by micro-habitat variation and/or genetic polymorphism to determine 1) the strength of linkage between fur color and local substrate color, and 2) the divergence in fur coloration between two genetic clades, representing cryptic species, throughout the complete range of the African desert jerboas (Jaculus jaculus). We used a combination of museum and field-collected specimens, remote sensing tools, satellite and digital photography and molecular genetic and phylogenetic met…
Parasite-induced behavioral change: mechanisms.
2010
Animal behavior and parasitism are more tightly linked than commonly thought. One of the most astonishing phenomena in host–parasite antagonistic interactions is ‘host manipulation,’ that is, the ability of a parasite to alter the behavior of its host in ways that appear to increase parasite fitness at the expense of host fitness. The mechanisms by which a parasite hijacks the behavior of its host have been explored using ethopharmacological and immunocytochemical approaches or carrying out a large-scale proteomic study on manipulated host’s brain. These few mechanistic studies have confirmed both the complexity of host manipulation by parasites and the importance of understanding the molec…