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Notre compréhension de la nature de la vie du royaume d’Haïti, jeune état qui émerge du tumulte de la révolution haïtienne, est masquée par les silences d’une archive historique et littéraire souvent problématiques. Depuis 2015, une équipe internationale de chercheurs des Etats-Unis et d’Haïti a entrepris des recherches archéologiques sur le site de Sans-Souci classé au Patrimoine Mondial de l’Unesco. Le palais royal de Sans-Souci fut une composante matérielle clé des stratégies du pouvoir royal du royaume d’Haïti et a servi de centre de gravité politique durant le règne de Henri Christophe. Malgré le rôle historique, central et important que ce site a joué dans la mémoire historique haïtienne, seule une étude archéologique minime a été conduite au sein du palais. Adoptant une stratégie de recherche multidimensionnelle incluant la modélisation 3D, le radar a pénétration de sol et la fouille ciblée, le Project Archéologique de Milot (Milot Archaeological Project, MAP) apporte un nouvel éclairage sur la chronologie architecturale du site, la nature de la vie matérielle derrière les murs du palais et sur les réseaux économiques, à la fois régionaux et à longue distance, dans lesquels le royaume était intégré. Cet article résume les récents résultats du MAP, soulignant le fort potentiel de la recherche archéologique à répondre aux questions sociales, politiques et économiques sur cette importante expérience de souveraineté politique. 

Balanced mating type polymorphisms offer a distinct window into the forces shaping sexual reproduction strategies. Multiple hermaphroditic genera in Juglandaceae, including walnuts (Juglans) and hickories (Carya), show a 1:1 genetic dimorphism for male versus female flowering order (heterodichogamy). We map two distinct Mendelian inheritance mechanisms to ancient (>37 million years old) genus-wide structural DNA polymorphisms. The dominant haplotype for female-first flowering inJuglanscontains tandem repeats of the 3′ untranslated region of a gene putatively involved in trehalose-6-phosphate metabolism and is associated with increasedcisgene expression in developing male flowers, possibly mediated by small RNAs. TheCaryalocus contains ~20 syntenic genes and shows molecular signatures of sex chromosome–like evolution. Inheritance mechanisms for heterodichogamy are deeply conserved, yet may occasionally turn over, as in sex determination. 

Abstract Mutations fuel evolution while also causing diseases like cancer. Epigenome-targeted DNA repair can help organisms protect important genomic regions from mutation. However, the adaptive value, mechanistic diversity, and evolution of epigenome-targeted DNA repair systems across the tree of life remain unresolved. Here, we investigated the evolution of histone reader domains fused to the DNA repair protein MSH6 (MutS Homolog 6) across over 4,000 eukaryotes. We uncovered a paradigmatic example of convergent evolution: MSH6 has independently acquired distinct histone reader domains; PWWP (metazoa) and Tudor (plants), previously shown to target histone modifications in active genes in humans (H3K36me3) and Arabidopsis (H3K4me1). Conservation in MSH6 histone reader domains shows signatures of natural selection, particularly for amino acids that bind specific histone modifications. Species that have gained or retained MSH6 histone readers tend to have larger genome sizes, especially marked by significantly more introns in genic regions. These patterns support previous theoretical predictions about the co-evolution of genome architectures and mutation rate heterogeneity. The evolution of epigenome-targeted DNA repair has implications for genome evolution, health, and the mutational origins of genetic diversity across the tree of life. 

Abstract BackgroundIn several eukaryotes, DNA methylation occurs within the coding regions of many genes, termed gene body methylation (GbM). Whereas the role of DNA methylation on the silencing of transposons and repetitive DNA is well understood, gene body methylation is not associated with transcriptional repression, and its biological importance remains unclear. ResultsWe report a newly discovered type of GbM in plants, which is under constitutive addition and removal by dynamic methylation modifiers in all cells, including the germline. Methylation at Dynamic GbM genes is removed by the DRDD demethylation pathway and added by an unknown source of de novo methylation, most likely the maintenance methyltransferase MET1. We show that the Dynamic GbM state is present at homologous genes across divergent lineages spanning over 100 million years, indicating evolutionary conservation. We demonstrate that Dynamic GbM is tightly associated with the presence of a promoter or regulatory chromatin state within the gene body, in contrast to other gene body methylated genes. We find Dynamic GbM is associated with enhanced gene expression plasticity across development and diverse physiological conditions, whereas stably methylated GbM genes exhibit reduced plasticity. Dynamic GbM genes exhibit reduced dynamic range indrddmutants, indicating a causal link between DNA demethylation and enhanced gene expression plasticity. ConclusionsWe propose a new model for GbM in regulating gene expression plasticity, including a novel type of GbM in which increased gene expression plasticity is associated with the activity of DNA methylation writers and erasers and the enrichment of a regulatory chromatin state. 

This paper synthesizes recent archaeological research on the Kingdom of Haiti, a short-lived experiment in political sovereignty founded in the years following the Haitian Revolution. I will explore the potential for an archaeology of sovereignty in the Black Atlantic world. Examining both architectural spaces and artifacts recovered from the palace of Sans-Souci, royal residence of King Henry Christophe, this paper highlights a constellation of material practices that fostered an emerging ideology of authority in postrevolution Haiti. Collectively, this research is revealing how political agents drew creatively and strategically from both European material culture and Afro-Caribbean traditions in the practice of political authority in the Kingdom of Haiti, casting new light on the complex nature of sovereignty after slavery in the Age of Revolutions. 

Abstract Genome-wide association studies (GWAS) are integral for studying genotype-phenotype relationships and gaining a deeper understanding of the genetic architecture underlying trait variation. A plethora of genetic associations between distinct loci and various traits have been successfully discovered and published for the model plant Arabidopsis thaliana. This success and the free availability of full genomes and phenotypic data for more than 1,000 different natural inbred lines led to the development of several data repositories. AraPheno (https://arapheno.1001genomes.org) serves as a central repository of population-scale phenotypes in A. thaliana, while the AraGWAS Catalog (https://aragwas.1001genomes.org) provides a publicly available, manually curated and standardized collection of marker-trait associations for all available phenotypes from AraPheno. In this major update, we introduce the next generation of both platforms, including new data, features and tools. We included novel results on associations between knockout-mutations and all AraPheno traits. Furthermore, AraPheno has been extended to display RNA-Seq data for hundreds of accessions, providing expression information for over 28 000 genes for these accessions. All data, including the imputed genotype matrix used for GWAS, are easily downloadable via the respective databases.