Special seminar - Georg Hochberg: Chance and purpose in the evolution of protein complexes
- Datum: 25.11.2019
- Uhrzeit: 14:00 - 15:00
- Vortragende(r): Georg Hochberg vom MPI für terrestrische Mikrobiologie in Marburg
- Ort: MPI Plön
- Raum: Hörsaal
- Gastgeber: Paul Rainey
Abstract (auf Englisch):
The role of
chance has a rich and controversial history in evolutionary
theory. On one side
of the spectrum lies extreme adaptionism, which assigns purpose
to all features
of organisms, assuming that they are highly optimized by natural
selection.
Chance plays a minimal role in this view, because selection so
powerful that it
always finds globally optimal solutions. On the other side of
the spectrum lies
Stephen Jay Gould’s view that evolution is so dominated by
random chance
events, that if we were to ‘replay the tape of life’, evolution
would take an almost
unrecognizably different path from our own. We use the evolution
of protein
complexes as a model system to empirically study the role of
chance and purpose
in their evolution. Using ancestral sequence reconstruction and
biochemical
characterization of resurrected protein complexes I will show
that a universal
mutational ratchet entrenches and preserves protein complexes,
even if they
serve no functional purpose. Further, I will present a
phylogenetic method to
directly quantify the rate at which protein-protein interactions
change due to
chance alone and present data showing that this occurs at a
remarkably uniform
rate in a family of dimeric transcription factors. Taken
together, these
results imply that chance plays a surprising and important role
in molecular
evolution that makes evolution somewhat predictable on very long
time-scales.