BEGIN:VCALENDAR VERSION:2.0 PRODID:-//Talks.cam//talks.cam.ac.uk// X-WR-CALNAME:Talks.cam BEGIN:VEVENT SUMMARY:When Turing meets Waddington: Theory of mechanochemical patterning in biphasic biological tissues - Dr Adrien Hallou\, Gurdon Institute & \; Cavendish Laboratory DTSTART:20211104T130000Z DTEND:20211104T140000Z UID:TALK165172@talks.cam.ac.uk CONTACT:Dr Sandra Petrus-Reurer DESCRIPTION:The starting point of a research project is usually a hypothes is or a model prediction that one would like to confirm or infirm\, or may be an observation that one would like to rationalize with the help of a mo del. However\, the foundation of the research I shall present in my talk\, was none of these\, but a letter (AMT/D/5\, Alan Turing Archive\, King’ s College Archive Centre\, Cambridge) sent by the famous biologist Conrad Waddington to Alan Turing in 1952! In this letter\, Waddington thanks Turi ng for sending a reprint of his seminal paper "The chemical basis of morph ogenesis" (Philosophical Transactions of the Royal Society of London\, vol . 237\,​ 1952\, p. 37-72) and raise several concerns about the applicabi lity of Turing’s reaction-diffusion model to biological developmental sy stems\, questioning its limitation to reproduce some observed behaviours i n embryonic development such as pattern scaling with tissue size or the ge neration of a spatial pattern of discrete cell types. Unfortunately\, it s eems that this letter remained unanswered\, certainly due to the untimely death of Turing. In my talk\, I will present a minimal model trying to ans wer Waddington objections to Turing’s model and which combines tissue me chanics with morphogen turnover and transport to explore new routes to pat terning. This active description couples morphogen reaction and diffusion\ , which impact cell differentiation and tissue mechanics\, to a two-phase poroelastic rheology\, where one tissue phase consists of a poroelastic ce ll network and the other one of a permeating extracellular fluid\, which p rovides feedback by actively transporting morphogens. While this model enc ompasses previous theories approximating tissues to inert monophasic media \, such as Turing’s reaction–diffusion model\, it overcomes some of th eir key limitations permitting pattern formation via any two-species bioch emical kinetics due to mechanically induced cross diffusion flows. Moreove r\, I will describe a qualitatively different advection-driven Keller–Se gel like instability which allows for the formation of patterns with a sin gle morphogen and whose fundamental mode pattern robustly scales with tiss ue size. I will discuss the potential relevance of these findings for tiss ue morphogenesis. LOCATION:King Richard Room\, Darwin College END:VEVENT END:VCALENDAR