Analysis of the P. lividus sea urchin genome highlights contrasting trends of genomic and regulatory evolution in deuterostomes

Sea urchins are emblematic models in developmental biology and display several characteristics that set them apart from other deuterostomes. To uncover the genomic cues that may underlie these specificities, we generated a chromosome-scale genome assembly for the sea urchin Paracentrotus lividus and an extensive gene expression and epigenetic profiles of its embryonic development. We found that, unlike vertebrates, sea urchins retained ancestral chromosomal linkages but underwent very fast intrachromosomal gene order mixing. We identified a burst of gene duplication in the echinoid lineage and showed that some of these expanded genes have been recruited in novel structures (water vascular system, Aristotle's lantern, and skeletogenic micromere lineage). Finally, we identified gene-regulatory modules conserved between sea urchins and chordates. Our results suggest that gene-regulatory networks controlling development can be conserved despite extensive gene order rearrangement

Numerical investigation of an experimental Kyropoulos process to grow silicon ingots for photovoltaic application

International audienc

Crystal Growth of Silicon for Photovoltaics

International audienc

Sexualidade e conjugalidade: a redefinição das relações de gênero na França contemporânea Sexuality and conjugality: the redefinition of gender relations in contemporary France

Um laço novo se estabeleceu entre sexualidade e vida conjugal nas últimas décadas do século XX. Tradicionalmente o direito à atividade sexual era adquirido com o estatuto de sujeito casado; hoje em dia, o intercâmbio sexual passou a ser o motor interno da conjugalidade. No entanto, esta inversão não gerou uma transformação completa das relações de gênero. A análise das mudanças dos comportamentos na França contemporânea mostra sem dúvida uma aproximação das trajetórias sexuais femininas e masculinas, e o desenvolvimento dum valor de reciprocidade entre parceiros. Mas o exame mais preciso do confronto dos homens e das mulheres nas várias etapas do intercâmbio sexual sugere a permanência de uma divergência de gênero: tanto a socialização adolescente como o curso da vida conjugal continuam sustentando interpretações muito assimétricas da sexualidade, nas quais o desejo feminino tem menos legitimidade do que o masculino.<br>The relation between sexuality and conjugality has been deeply redefined in the last decades of the XXth century. Whereas sex was traditionally a right and an attribute of married people, sexual exchange has presently become the inner driving force in contemporary conjugality. Nevertheless, this reversal has not brought about radical shifts in gender relations. An analysis of trends in sexual behaviours in France doubtless shows the closing of the gap between male and female sexual trajectories and the rise of a value of reciprocity between partners. But a closer examination of the confronting of men and women at the various stages of sexual exchange suggests the permanence of a strong gender divergence: teen age socialization, as well as the very course of conjugal sex life continue fostering very assimetrical interpretations of sexuality, in which female desire is always less legitimate than the male one