Lifemap: Exploring the Entire Tree of Life

International audienceThe Tree of Life (ToL) is meant to be a unique representation of the evolutionary relationships between all species on earth. Huge efforts are made to assemble such a large tree, helped by the decrease of sequencing costs and improved methods to reconstruct and combine phylogenies, but no tool exists today to explore the ToL in its entirety in a satisfying manner. By combining methods used in modern cartography, such as OpenStreetMap, with a new way of representing tree-like structures, I created Lifemap, a tool allowing the exploration of a complete representation of the ToL (between 800,000 and 2.2 million species depending on the data source) in a zoomable interface. A server version of Lifemap also allows users to visualize their own trees. This should help researchers in ecology and evolutionary biology in their everyday work, but may also permit the diffusion to a broader audience of our current knowledge of the evolutionary relationships linking all organisms

La double nature du social: une conversation sur le temps, le transcendantal, la vie, etc. [entretien avec Maurice Bloch]

Can a theory emerge from the thousand ways of being born again by ethnographic research? Is rebirth a specifically human phenomenon? Can we experience rebirth in the absence of ritual? These are the types of questions Maurice Bloch discusses in the interview. He has come across these issues on several occasions during his career and has developed the theory that is the only species with a transcendental approach to the social, that is, with a capacity to construct roles and imaginary communities

Hill Jonathan D., Made-from-bone. Trickster myths, music, and history from the Amazon

Toute mythologie ne se lit pas comme un roman. C’est bien l’intérêt et le succès de ce livre que d’être à ce titre une exception. Pour parvenir à ce résultat que tout ethnographe sait ardu, Jonathan Hill s’est donné en apparence un objectif modeste sur le plan théorique, celui de « fournir un ensemble complet de traductions anglaises des récits Wakuénai sur le passé mythique et ses transformations » (p. i). Dans ce groupe de langue arawak du haut río Negro, la figure mythique centrale est Mad..

L'arbre du vivant: Etat des lieux et visualisation

National audienceL'arbre de la vie représente l'intégralité des liens évolutifs qui unissent les espèces de notre planète. Sa reconstruction fait l'objet de nombreuses études, aidées par l'essor des nouvelles techniques de séquençage à haut débit. Sa visualisation est un véritable défi. L'évolution des espèces depuis plus de 3,5 milliards d'années a conduit à la biodiversité actuelle, dont nous ne connaissons qu'une petite partie. Les liens de parenté, ou liens évolutifs, qui existent entre toutes ces espèces forment un arbre, nommé « arbre de la vie » (ou arbre du vivant), où chaque feuille représente une espèce et chaque noeud un ancêtre, à la manière des arbres généalogiques

Brunei

The placing of energy under the direct authority of the Sultan, then the ministerial reshuffle of May 2022, marked the desire to better control the ministers in an increasingly changing international and energetic context, while redefining its security. The pandemic-induced economic crisis, which spared the Sultanate in 2020, hit it hard in 2021, resulting in the departure of some temporary workers. A sign of the times, the government has taken advantage of Brunei’s presidency of ASEAN to promote the creation of a regional Center for Climate Change, based in the Sultanate, and women occupy a growing place in the senior administration

Tanglegrams are misleading for visual evaluation of tree congruence

Evolutionary Biologists are often faced with the need to compare phylogenetic trees. One popular method consists in visualizing the trees face to face with links connecting matching taxa. These tanglegrams are optimized beforehand so that the number of lines crossing (the entanglement) is minimal. This representation is implicitly justified by the expectation that the level of entanglement is correlated with the level of similarity (or congruence) between the trees compared. Using simulations, we show that this correlation is actually very weak, which should preclude the use of such technique for getting insight into the level of congruence between trees

“Ant” and “Grasshopper” Life-History Strategies in Saccharomyces cerevisiae

From the evolutionary and ecological points of view, it is essential to distinguish between the genetic and environmental components of the variability of life-history traits and of their trade-offs. Among the factors affecting this variability, the resource uptake rate deserves particular attention, because it depends on both the environment and the genetic background of the individuals. In order to unravel the bases of the life-history strategies in yeast, we grew a collection of twelve strains of Saccharomyces cerevisiae from different industrial and geographical origins in three culture media differing for their glucose content. Using a population dynamics model to fit the change of population size over time, we estimated the intrinsic growth rate (r), the carrying capacity (K), the mean cell size and the glucose consumption rate per cell. The life-history traits, as well as the glucose consumption rate, displayed large genetic and plastic variability and genetic-by-environment interactions. Within each medium, growth rate and carrying capacity were not correlated, but a marked trade-off between these traits was observed over the media, with high K and low r in the glucose rich medium and low K and high r in the other media. The cell size was tightly negatively correlated to carrying capacity in all conditions. The resource consumption rate appeared to be a clear-cut determinant of both the carrying capacity and the cell size in all media, since it accounted for 37% to 84% of the variation of those traits. In a given medium, the strains that consume glucose at high rate have large cell size and low carrying capacity, while the strains that consume glucose at low rate have small cell size but high carrying capacity. These two contrasted behaviors may be metaphorically defined as “ant” and “grasshopper” strategies of resource utilization. Interestingly, a strain may be “ant” in one medium and “grasshopper” in another. These life-history strategies are discussed with regards to yeast physiology, and in an evolutionary perspective

Éditorial

À l’heure où l’anthropologie et l’histoire de l’art se retrouvent sur la question des images pour répudier le paradigme de la signification et de la représentation mimétique, il n’est pas inutile de reposer la question, classique dans les deux disciplines, de la figuration de l’invisible. C’est en effet souvent parce que les images établissent un rapport complexe entre visible et invisible, et plus largement entre perçu et non perçu, qu’elles peuvent manifester certaines des propriétés qui le..

Oakdale Suzanne, I foresee my life. The ritual performance of autobiography in an Amazonian community, University of Nebraska Press, Lincoln, 2005, xvi + 206 p., bibl., index

En s’appuyant sur l’ethnographie de trois rituels différents qui, tous, engagent une mise en récit d’un épisode autobiographique, Suzanne Oakdale cherche à reconstruire une définition du « sujet » chez les Kayabi (groupe Tupi du Brésil central), dans sa constitution au cours de la vie individuelle comme lors de performances rituelles ponctuelles. Par « autobiographie » il ne faut pas entendre, comme elle le souligne dans l’introduction, un récit de vie complet, mais bien l’énonciation d’un ép..