Speaker
Bartlomiej Waclaw
(University of Edinburgh)
Description
Migration between different habitats is ubiquitous among
biological populations. Here I will discuss a simple model
for evolution of asexual organisms in two different habitats
coupled by one-way migration as well as the network of
possible mutations. This gives rise to clusters of closely
related genotypes — "quasispecies". The habitats are assumed
to have different fitness landscapes, i.e., organisms which
are well-adapted in the primary habitat are likely to be
maladapted in the secondary habitat. The model undergoes a
dynamical phase transition: at a critical value of the
migration rate, the time to reach the steady state diverges.
Above the transition, the population is dominated by
immigrants from the primary habitat. Below the transition,
the genetic composition of the population is highly
non-trivial, with multiple coexisting "quasispecies" which
are not native to either habitat. Using results from
localization theory, I will show that the critical migration
rate may be very small — demonstrating that evolutionary
outcomes can be very sensitive to even a small amount of
migration.
