"Single-cell morphometrics reveals ancestral principles of notochord development"

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• Toby Andrews, Department of Zoology, Univeristy of Cambridge
• Monday 07 June 2021, 14:30-15:30
• Online.

If you have a question about this talk, please contact Elena Scarpa.

recording can be found here: https://www.youtube.com/watch?v=Qh_hOcdkup8

Embryonic tissues are sculpted by the dynamic behaviours of their constituent cells. In turn, evolutionary transitions in form arise from tweaks in those behaviours. To define how evolution acts on developmental programmes, new methods are needed to map out morphogenesis across a diversity of organisms, including non-model systems where experimental traction is limited. Here, we have applied a quantitative approach to define how the notochord forms during the development of amphioxus – a basally-branching chordate, used to infer ancestral properties in the phylum. Using a single-cell morphometrics pipeline, we quantify the geometries of thousands of amphioxus notochord cells, and project them into a morphospace, in which they organise into branching trajectories of cell shape change. Focussing on a single region, we first define stepwise cell shape transitions that enforce a constant rate of tissue elongation in the notochord. Within this, we use mathematical modelling to predict a synergistic relationship between intercalation and growth in generating length. By spatially mapping trajectories, we go on to identify conspicuous regional variation, both in developmental timing and trajectory topology. Finally, we show experimentally that posterior cell division modulates notochord length by regulating the number of cells entering each shape trajectory. Our approach offers a new way of seeing in the study of tissue morphogenesis, that enables holistic analysis of cell behaviours defining tissue geometry. It also reveals an unexpectedly complex scheme of notochord morphogenesis that might have operated in the first chordates.

This talk is part of the Morphogenesis Seminar Series series.

This talk is included in these lists:

• Graduate-Seminars
• Morphogenesis Seminar Series
• Online

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