I am an evolutionary geneticist, interested
in questions of how the interactions among genes evolve,
and how those interactions in turn affect processes of
evolution. My work has both empirical and theoretical components,
and one of my constant goals is to integrate the two as
much as possible, so that theoretical results generate
predictions for experiments, while experimental results
help focus future theoretical work.
I have three main areas of research:
The evolution of recombination rates in laboratory
populations of the roundworm Caenorhabditis elegans. Because
the effective recombination rate of C. elegans can
be manipulated at several levels, we are able to
test evolutionary models of recombination by exposing
populations with different recombination rates to
environmental or genetic perturbations that would
be predicted to provide an advantage to recombination. For
example, one broad class of models predicts that populations
with high recombination rates should adapt more quickly
to novel environments. If fitness increases
more rapidly in high-recombination populations of C. elegans than
in low-recombination populations when both are subjected
to the same new environment, then this class of models
is supported. Molecular approaches for determining
what loci are involved in adaptation can then be
applied to help determine what specific processes
are involved in providing an advantage to recombination.
The evolution of fitness via compensatory mutations
in C. elegans. If a genotype has
had its fitness reduced due to mutations, is it more
likely to encounter mutations at other loci that increase
its fitness? In
other words, can mutations, which might otherwise be
neutral or deleterious, increase fitness by compensating
for the disadvantageous effects of mutations at other
loci? How
common are such “compensatory mutations;” what
are their effects; and to what extent do their effects
depend on the genetic specifics of the original fitness-reducing
mutations? The answer to this question has implications
for our understanding of the degree to which genomes
are integrated, which in turn informs our understanding
of processes like speciation and the evolution of sex. In
addition, this question has implications for species
conservation, since endangered populations are expected to
accumulate fitness-reducing mutations; if such populations
have a high rate of compensatory mutation, they may be more
likely to survive than we originally thought. We
address such questions by allowing strains of C. elegans that
are “knockouts” at
arbitrarily chosen loci (i.e., they’ve had stretches
of protein-coding DNA excised completely) to evolve. Any
increases in fitness are then due to compensatory mutations
at other loci. Using a combination of statistical
and genetic approaches, we can estimate the numbers
and effects of compensatory mutations across large
numbers of lines.
Theoretical models of the evolution of sex and recombination.
I use computer simulation as well as numerical and
analytical approaches to achieve two ends: (1) to generate
experimentally useful predictions from the wide array of models
currently available to explain sex and recombination; and (2)
to integrate these models into a common, modern model
framework – a
stochastic framework explicitly considering the probability
of fixation of alleles that affect the rate of sex
or recombination.
I am interested in graduate students who are driven by conceptual
issues in evolutionary biology, and who want to bring
together some combination of laboratory evolution, genetics,
and mathematical/computational techniques to address those issues.
I encourage independence, and therefore don’t require
that students’ interests
and plans perfectly mirror my own; but, of course,
the more overlap there is, the better I am able to act as an
advisor.
Haag, E. S., H. Chamberlin, A. Coghlan,
D. H. A. Fitch, A. D. Peters, & H. Schulenburg. 2007. Caenorhabditis
evolution: If they all look alike, you aren’t
looking hard enough! Trends in Genetics,
in press.
Peters, A. D. & C. M. Lively. 2007. Short-
and long-term benefits and detriments to recombination
under antagonistic coevolution. Journal
of Evolutionary Biology, in press.
adpeters1@wisc.edu
