Speaker
Masahiko Ueda
(Department of Basic Science, The University of Tokyo)
Description
Stronger selection implies faster evolution---that is, the greater the
force, the faster the change. This apparently self-evident proposition,
however, is derived under the assumption that genetic variation within a
population is primarily supplied by mutation (i.e. mutation-driven
evolution). Here, we show that this proposition does not actually hold
for recombination-driven evolution, i.e. evolution in which genetic
variation is primarily created by recombination rather than mutation.
By numerically investigating population genetics models of
recombination, migration and selection, we demonstrate
that stronger selection can slow down evolution on a perfectly smooth
fitness landscape. Through simple analytical calculation, this apparently
counter-intuitive result is shown to stem from two opposing effects of
natural selection on the rate of evolution. On the one hand, natural
selection tends to increase the rate of evolution by increasing
the fixation probability of fitter genotypes. One the other hand,
however, it tends to decrease the rate of evolution by
decreasing the chance of recombination between immigrants and resident
individuals. As a consequence of these opposing effects, there is a
finite selection pressure maximizing the rate of evolution; hence, the
``change'' depends on the ``force'' non-monotonically.
Primary author
Masahiko Ueda
(Department of Basic Science, The University of Tokyo)
Co-authors
Kunihiko Kaneko
(Department of Basic Science, The University of Tokyo)
Nobuto Takeuchi
(Department of Basic Science, The University of Tokyo)
