Freitag, 11.01.2019, 16ct, V3-204: Christiane Fuchs (Universität Bielefeld)
Stochastic Modelling and Inference of Cellular Processes
The molecular biology of life seems inaccessibly complex, and gene expression is an essential part of it. It is subject to random variation and not exactly predictable. Still, mathematical models and statistical inference pave the way towards the identification of underlying gene regulatory processes. In contrast to deterministic models, stochastic processes capture the randomness of natural phenomena and result in more reliable predictions of cellular dynamics. Stochastic models and their parameter estimation have to take into account the nature of molecular-biological data, including experimental techniques and measurement error.
This talk presents according modelling and estimation techniques and their applications: the derivation of mRNA contents in single cells; the identification of differently regulated cells from heterogeneous populations using mixed models; and parameter estimation for stochastic differential equations to understand translation kinetics after mRNA transfection.
Freitag, 19.10.2018, 16ct, V3-204: Philip Gerrish, Atlanta/Bielefeld
Is there sex on other planets?
We ask the question: if an alien system of self-replicating
entities were discovered, should we expect sex and/or recombination to
be features of this system? Put differently, is there something about
mutation and natural selection that inherently promotes the evolution of
sex and recombination? Current theory finds many special circumstances
in which sex and recombination might be expected to evolve, but this
“patchwork of special cases” (with many holes) does not seem to fit the
observations: in nature, sex and recombination are everywhere — spanning
all environments and all levels of organismal size and complexity.
Increasingly, even species traditionally thought to be asexual have been
caught “having sex on the sly”. The observations, therefore, seem to
call for an encompassing feature common to living things in general that
promotes the evolution of sex and recombination. And we think we may
have a candidate! We think this general feature might be none other than
natural selection itself. I will show you what we’re thinking and how it
works, will go through the case of structured populations which has a
nice intuitive “visual proof” as well as a presentable “simplest case”
proof, and will show you how far we’ve gotten with the full problem,
with hopes for some nice feedback.
This is joint work with Ben Sprung (Philadelphia), Julien Chevallier
(Grenoble), and Bernard Ycart (Grenoble).