organisation - the Instituto Gulbenkian de Ciência

EVOLUTIONARY
GENETICS
Henrique Teotónio Principal Investigator
PhD in Evolutionary Genetics, Universidade de Lisboa, Portugal, 2000
Postdoc, Princeton University
Postdoc, University of Oregon Eugene
Principal Investigator at the IGC since 2003
The study of natural selection and its consequences are central to any understanding
of biology because they provide a framework for the origin, divergence
and maintenance of diversity. We are specifically investigating how the
interactions between mating between individuals and meiotic recombination
determine the evolution of polygenic phenotypes. For this we use populations
of C. elegans with standing diversity and alternative mating systems in demographic
conditions defined by discrete non-overlapping generations at constant
high population sizes. We then manipulate the frequency of environmental
change and follow the evolution of phenotypes and genotypes in real time.
Analysis of data involves computer simulations of experimental evolution under
several selection scenarios.
THE INFLUENCE OF MATING, RECOMBINATION AND NATURAL SELECTION
IN C. elegans EXPERIMENTAL EVOLUTION
Understanding adaptation following an environmental shift is necessary to
explain the evolution of biological diversity. The mechanisms thought to limit
diversity mating among related individuals because they cause inbreeding, meiotic
recombination because they determine extent of gametic linkage among
loci, and the degree of dominance or epistatic gene interactions because they
define natural selection. We aim to resolve the influence of these mechanisms
on the adaptation of large populations by employing an experimental evolution
approach in the androdioecious nematode Caenorhabditis elegans under
varying levels of outcrossing rates, initial standing genetic variation and frequency
of environmental change. During experimental evolution several levels
of structural organization, from fitness-proxy and life history phenotypes to
genome wide RNA expression are characterized in their genetic and environmental
components.
GROUP MEMBERS
Ivo Chelo (Post-doc)
Yoannis Theologidis (Post-doc)
Peter Sandner (Post-doc, started in June)
Sara Carvalho (PhD student)
Bruno Afonso (PhD student)
Christine Goy (Lab Manager)
Judit Nedli (Technician, started in September)
COLLABORATORS
Matt Rockman (New York University, USA)
Boris Shraiman (University of California, Santa Barbara, USA)
FUNDING
European Research Council (ERC), European Commission
Human Frontiers Science Programme (HFSP)
PUBLIC ENGAGEMENT IN SCIENCE
Radio Interview, February
The project also includes hitchhiking mapping of relevant loci, by whole
genome linkage disequilibrium (LD) association mapping and computer simulations
of directional and balancing selection during experimental evolution.
We have completed the characterization of >350 SNPs in experimentally evolved
populations and the characterization of reproduction and viability under several
osmotic and anoxic environmental stress conditions.
ROLE OF GENETIC INTERACTIONS AND RECOMBINATION IN EXPERIMENTAL
EVOLUTION OF C. elegans
Adaptation from standing genetic variation is central to the evolution of phenotypes,
yet its dependence on the molecular details that connect genotype,
phenotype, and fitness is a major unsolved problem in genetics. The effect of
recombination, in particular, is expected to depend on the extent of genetic
interaction among alleles. We propose a multidisciplinary investigation of the
roles of recombination and genetic interactions. We will study laboratory adaptation
of C. elegans populations that start with high genetic variability and are
engineered to have different rates of inbreeding and outcrossing. The project
integrates experimentally determined genome-wide genotype distributions,
multidimensional phenotype (gene expression) measurements, and fitness data
across 100 generations of laboratory populations that differ in their rates of
outcrossing. This integration forms the empirical test bed for theoretical models
of the role of genomic architecture in adaptation.
We will test the predicted positive correlation among non-additive genetic
effects and levels of linkage disequilibrium across the genome. The derivation
of three ancestral populations for experimental evolution with exclusive selfing,
mixed selfing and outcrossing and obligatory outcrossing has been achieved,
as well as derivation of recombinant inbred lines from population at genetic
equilibrium.
IGC ANNUAL REPORT ‘11
RESEARCH GROUPS
65