Le droit suisse des sociétés en 2017: modifications législatives, jurisprudence et doctrine

La contribution présente, sous une forme synthétique, les principales modifications législatives, entrées en vigueur et en cours, la jurisprudence ainsi que la doctrine publiée en droit suisse des sociétés en 2017. Les modifications législatives (I.) accordent une large place à la présentation de la révision projetée du droit de la société anonyme, tout en s’intéressant également à d’autres thèmes, tel que l’initiative populaire « Entreprises responsables - pour protéger l’être humain et l’environnement ». Les résumés de jurisprudence sont classés par forme de société et décrivent en premier lieu les arrêts publiés (II.). Finalement, la doctrine est présentée en fonction du thème traité (III.)

Vitellogenin gene family in vertebrates: evolution and functions

The vitellogenin gene family is constituted of variable gene numbers encoding for polypeptides that are precursors of yolk proteins and derivatives in oviparous and ovoviviparous vertebrates. The comprehension of which mechanisms have shaped the evolution of vtg gene family represents an attractive field of research. The primary intent of this review is to summarize the evolutionary hypotheses that have been proposed over recent decades, highlighting the differences between the proposed models. Overall in vertebrates the evolutionary history of this gene family is the result of complex modifications deeply influenced by events such as Whole Genome Duplications (WGDs), lineage-specific gene losses and duplications. Interestingly the last hypothesis allowed to date the vitellogenin gene cluster origin in the common ancestor of gnathostomes. In addition, in the last decades, several works evidenced non-nutritional functions such as antibacterial, immunological and antioxidant activities overcoming its classical view as a simple source of nourishment for the developing embryos

Transposable elements in vertebrates: species evolution and environmental adaptation

The evolutionary success of species is strictly related to their genome in terms of composition and functionality. Transposable elements (TEs) represent a considerable fraction of the nuclear DNA content, and given to their ability to spread throughout the genome, they are able to create genetic diversity at sequence, gene structure, and chromosome level. Vertebrates represent a highly successful taxon and its lineages are characterized by a variable TE content suggesting a different impact on the genome. In this manuscript, we highlight the importance of TEs in creating new regulatory sequences and genetic innovations extremely useful for diversification of vertebrates. Moreover, an increasing number of evidence suggests a link between TEs and environment. Indeed, given the richness of species adapted to a wide range of habitats and conditions, vertebrates are exposed to several ecological pressures with consequent effects on evolutionary adaptation

Shedding light upon the complex net of genome size, genome composition and environment in chordates

The nucleotype theory has been advanced on the basis of studies regarding genome size and composition in various plant and animal species, i.e. the influence that genome can have on the phenotype independently of the informational content of DNA. It has also been noted that during evolution various interactions between different environmental factors and genome structural and functional parameters would have occurred. In this review, changes in genome size, transposon content, and base composition occurred during the evolution of chordates were examined. Many environmental stresses, such as temperature, can act on transposons and through these on genome size. Temperature is also one of the most important elements of natural selection able to interact both with base composition and genome size. It has been evidenced that temperature exerts a direct influence on base composition and its increase would have led to an higher content of genome GC-rich components during the evolution of chordates, in particular in endotherms. Temperature would have controlled the rate of biosynthesis in G1 phase and consequently the cell cycle duration which in turn would have interacted with genome size. The combined action of temperature, base composition, and genome size would also have been very important in controlling the metabolic rate. Finally, another important aspect of the nucleotypic effect is the influence that genome size and cell cycle duration, in correlation with environmental temperature, would have exert on embryo and larval development, very important for environmental adaptation. In conclusion, studies here reviewed to confirm the existence in chordates of a mutual influence between environment and genome non-coding components that would have played an important role in the evolution of these animals especially in environmental adaptation processes

Karyological and genetic variation in Middle Eastern lacertid lizards, Lacerta laevis and the Lacerta kulzeri complex: a case of chromosomal allopatric speciation

Abstract Karyological (standard and C, Ag-NOR and Alu-I banding methods) and mtDNA analyses (cytochrome b and 12S rRNA) were conducted on specimens from eight allopatric populations of the Lacerta kulzeri complex. Parallel analyses were performed for comparison on Lacerta laevis specimens. Karyological and molecular studies support the morphological and ethological evidence indicating the speci¢c separation between Lacerta laevis and Lacerta kulzeri. In the Lacerta kulzeri complex, chromosomal analysis substantiated an interpopulation di¡erentiation roughly along a north^south trend, mainly regarding the sex chromosome morphology and heterochromatin. The cytochrome b and 12S rRNA gene analyses showed minor genetic di¡erences that were considerably smaller than those commonly found in genetically isolated populations. The L. kulzeri populations from Barouk, Druze and Hermon show a mean genetic distance that, in other saurians, characterises subspecies. The conditions found in L. laevis and L. kulzeri are reminiscent of King's model of chromosomal primary allopatry and support the hypothesis that in these lacertid lizards chromosome variations can become ¢xed before the accumulation of the genetic mutations

The Complete Mitochondrial Genomes of Six Heterodont Bivalves (Tellinoidea and Solenoidea): Variable Gene Arrangements and Phylogenetic Implications

BACKGROUND: Taxonomy and phylogeny of subclass Heterodonta including Tellinoidea are long-debated issues and a complete agreement has not been reached yet. Mitochondrial (mt) genomes have been proved to be a powerful tool in resolving phylogenetic relationship. However, to date, only ten complete mitochondrial genomes of Heterodonta, which is by far the most diverse major group of Bivalvia, have been determined. In this paper, we newly sequenced the complete mt genomes of six species belonging to Heterodonta in order to resolve some problematical relationships among this subclass. PRINCIPAL FINDINGS: The complete mt genomes of six species vary in size from 16,352 bp to 18,182. Hairpin-like secondary structures are found in the largest non-coding regions of six freshly sequenced mt genomes, five of which contain tandem repeats. It is noteworthy that two species belonging to the same genus show different gene arrangements with three translocations. The phylogenetic analysis of Heterodonta indicates that Sinonovacula constricta, distant from the Solecurtidae belonging to Tellinoidea, is as a sister group with Solen grandis of family Solenidae. Besides, all five species of Tellinoidea cluster together, while Sanguinolaria diphos has closer relationship with Solecurtus divaricatus, Moerella iridescens and Semele scaba rather than with Sanguinolaria olivacea. CONCLUSIONS/SIGNIFICANCE: By comparative study of gene order rearrangements and phylogenetic relationships of the five species belonging to Tellinoidea, our results support that comparisons of mt gene order rearrangements, to some extent, are a useful tool for phylogenetic studies. Based on phylogenetic analyses of multiple protein-coding genes, we prefer classifying the genus Sinonovacula within the superfamily Solenoidea and not the superfamily Tellinoidea. Besides, both gene order and sequence data agree that Sanguinolaria (Psammobiidae) is not monophyletic. Nevertheless, more studies based on more mt genomes via combination of gene order and phylogenetic analysis are needed to further understand the phylogenetic relationships in subclass Heterodonta

Analysis of the African coelacanth genome sheds light on tetrapod evolution

It was a zoological sensation when a living specimen of the coelacanth was first discovered in 1938, as this lineage of lobe-finned fish was thought to have gone extinct 70 million years ago. The modern coelacanth looks remarkably similar to many of its ancient relatives, and its evolutionary proximity to our own fish ancestors provides a glimpse of the fish that first walked on land. Here we report the genome sequence of the African coelacanth, Latimeria chalumnae. Through a phylogenomic analysis, we conclude that the lungfish, and not the coelacanth, is the closest living relative of tetrapods. Coelacanth protein-coding genes are significantly more slowly evolving than those of tetrapods, unlike other genomic features . Analyses of changes in genes and regulatory elements during the vertebrate adaptation to land highlight genes involved in immunity, nitrogen excretion and the development of fins, tail, ear, eye, brain, and olfaction. Functional assays of enhancers involved in the fin-to-limb transition and in the emergence of extra-embryonic tissues demonstrate the importance of the coelacanth genome as a blueprint for understanding tetrapod evolution

Hox and ParaHox genes in bivalves molluscs.

In this study, we sought the presence and analysed the sequences of the Hox and ParaHox genes in bivalve molluscs. The clustered Hox genes play a central role in anterior-posterior axial patterning in bilaterian metazoa, whereas the ParaHox gene cluster is a paralogue (evolutionary sister) of the Hox cluster. Using polymerase chain reaction (PCR)-based approaches, we isolated nine different sequences in five species belonging to three of the main bivalve subclasses: Ensis ensis and Tapes philippinarum (Heterodonta), Pecten maximus and Mytilus galloprovincialis (Pteriomorphia), and Yoldia eightsi (Protobranchia). Comparison with the Hox and ParaHox genes of other bilaterians, particularly lophotrochozoans, allowed us to attribute six of these sequences to the Hox gene cluster (one to paralog group [PG] 3 class, and five to the central class), two to the ParaHox cluster and one to the Gbx gene family. The results of our investigation seem to indicate that homeotic Hox and ParaHox gene clusters are homogeneous for both presence and characteristics in molluscs. © 2003 Elsevier B.V. All rights reserved