BEGIN:VCALENDAR VERSION:2.0 PRODID:-//Talks.cam//talks.cam.ac.uk// X-WR-CALNAME:Talks.cam BEGIN:VEVENT SUMMARY:Matteusz: "\;Insights into the mechanism and evolution of glia l ensheathment"\; Renske: "\;Evolution of selfish multicellula rity: changes in gene regulation at the origin of multicellularity"\; - Renske Vroomans\; Matteusz Trylinski DTSTART:20211025T133000Z DTEND:20211025T143000Z UID:TALK162508@talks.cam.ac.uk CONTACT:102604 DESCRIPTION:*Matteusz Trylinski*\nCoordination of cellular behaviours enab les both the formation of tissues and complex organs during development an d the appearance of new structures during evolution. One of such events is the emergence of glial wrapping during Metazoan history\, which among oth ers increased the speed and the precision of information transfer along ax ons. Although we have a good understanding on the current mechanisms regul ating this process\, little is known about their evolutionary origin. \nH ere\, we address this question by using an evolutionary-conserved sensory organ\, the Drosophila thoracic microchaete. These organs are made of four lineage-related cells – two outer structural cells and two inner sensor y cells – that are organised in a concentric\, or “onion-like”\, fas hion. Given that homologous structures can be found in Tardigrades\, which have diverged from Arthropods over 500 million years ago\, we speculate t hat the mechanisms involved in the successive ensheathments during microch aete morphogenesis might be reminiscent of the ancestral state. \nIn part icular\, we investigate how\, following the first lineage division that gi ves rise to the outer-cell and inner-cell progenitors\, the future structu ral-sensory interface is generated\, and how the inner-cell progenitor is enwrapped by the outer-cell progenitor. Our preliminary results suggest th at this wrapping event combines both non-transcriptional effectors related to asymmetric cell division and transcriptional targets expressed by the inner-cell progenitor. \n\n*Renske Vroomans*\nMost multicellular organisms undergo some form of development and morphogenesis. Recent studies have s hown that many of the genetic tools to regulate these processes were alrea dy present in their unicellular ancestor. This suggests that the most ubiq uitous developmental processes may also be traced back all the way to the emergence of multicellularity itself. Furthermore\, the evolutionary trans ition to multicellularity may have predominantly required changes in regul ation and coordination\, more than changing the gene content. \nWe use evo lutionary models to study the evolution of cell adhesion and gene regulati on at the onset of multicellularity. We find that the physical properties of cell clusters can be sufficient to drive selection for cell adhesion. O nce cells evolve adhesion however\, their regulatory dynamics evolve as we ll: while cells evolve adhesion to survive collectively\, within such cohe sive clusters\, intercellular competition drives cells to behave "selfishl y" by dividing sooner and perform the collective task later. \nThe model d emonstrates how the transition to multicellularity may have driven a drast ic switch in cell behaviour\, leading to complex coordinated dynamics comp ared to the unicellular cousins\, without changing the genetic toolkit. LOCATION:Online END:VEVENT END:VCALENDAR