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CDB Seminar - William C. Ratcliff, Georgia Institute of Technology
10 February 2022, 3:00 pm–4:00 pm
Title: Exploring multicellularity via experimental evolution
This event is free.
Event Information
Open to
- All
Availability
- Yes
Cost
- Free
Organiser
-
Michael Wright – Cell and Developmental Biology
Host: Chris Barnes
Talk abstract: The origin of multicellularity was one of the most significant innovations in the history of life. Our understanding of the evolutionary processes underlying this transition remains limited, however, mainly because extant multicellular lineages are ancient and most transitional forms have been lost to extinction. We bridge this knowledge gap by evolving novel multicellularity in vivo, using the 'snowflake yeast' model system. In this talk, I'll focus on our most Multicellularity Long-Term Evolution Experiment (MuLTEE), in which we've put snowflake yeast through ~5,000 generations of selection. We'll examine how snowflake yeast evolve to be ~20,000x larger, and 10,000x biophysically tougher than their ancestors through a clever change in the way that cells interact within the group. Through a combination of multicellular biophysics and synthetic biology, we'll examine how two key steps in this transition: a multicellular life cycle and heritability of multicellular traits, arise 'for free'. If time permits, we'll examine early steps in the evolution of cellular differentiation. Our approach, which allows for the study of macroevolutionary processes over microevolutionary timescales, demonstrates that multicellularity is less evolutionarily constrained than previously thought.
Join Zoom Meeting:
https://ucl.zoom.us/j/99328593083?pwd=K2xVNzhPc1BZWlVSNVp2SXc5aURwQT09
Meeting ID: 993 2859 3083
Passcode: 067261
About the Speaker
William C. Ratcliff
at Georgia Tech
I am an evolutionary biologist broadly interested in the evolution of complex life. My Ph.D. training focused on the evolutionary stability of cooperation in the legume-rhizorium symbiosis. Here I developed new experimental methods to study how among-organism genetic conflict arises and can be mitigated. A similar evolutionary tension lies at the heart of all key events in the origin of complex life, termed the ‘Major Transitions in Evolution’: namely, how do new organisms arise and evolve to be more complex without succumbing to within-organism conflict? Studying the early evolution of multicellular organisms has been particularly difficult because these transitions occurred deep in the past, and transitional forms have largely lost to extinction. As a postdoc, I circumvented this constraint by creating a new approach to study the evolution of multicellularity: we evolved it de novo. Since founding my own research group at Georgia Tech in 2014, I have combined this approach with mathematical modeling and synthetic biology to examine how simple clumps of cells evolve to be more complex. Our research has shown how classical constraints in the origin of multicellularity –e.g., the origin of life cycles, multicellular development, cellular differentiation, and cellular interdependence– can be solved by Darwinian evolution.
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