organisation - the Instituto Gulbenkian de Ciência

EVOLUTIONARY
BIOLOGY
Isabel Gordo Principal Investigator
PhD in Evolutionary Biology, Edinburgh, 2002
Principal Investigator at IGC since 2004
link to external website
All natural populations have to adapt to new environments. Knowledge of the
genetics of adaptation should provide the centrepiece of a unified theory of
evolution. Despite its extreme importance, the process of adaptation is far from
being understood. For example: What is the rate at which positive Darwinian
selection occurs? Does the rate of adaptation depend on genetic background?
What is the distribution of fitness effects of mutations? Does adaptation involve
the fixation of mutations with small or large effects? How do mutations interact?
What are the relative costs and benefits in bacterial cells with high mutation
rates? These are some of the questions that we try to address.
ANTIBIOTIC RESISTANCE AND THE GEOMETRY OF COMPENSATORY EVOLUTION
The distribution of effects of beneficial mutations is key to our understanding
of biological adaptation. Fisher geometrical model of adaptation predicts
that this distribution should have a given functional form and should depend
on the genotype. Yet empirical estimates of this distribution are scarce and its
functional form is largely unknown. Here we study the rate and distribution of
adaptive mutations that compensate for the effect of a single deleterious mutation,
which causes antibiotic resistance.
GROUP MEMBERS
Ana Margarida Sousa (Post-doc)
Patrícia Brito (Post-doc)
João Batista (PhD student)
Migla Miskinyte (PhD student)
Sandra Trindade (PhD student)
Catarina Bourgard (Technician)
Maria Azevedo (Technician)
COLLABORATORS
Jocelyne Demengeot (IGC, Portugal)
Karina Xavier (IGC, Portugal)
Miguel Godinho Ferreira (IGC, Portugal)
Paulo Campos (Universidade Federal Rural de Pernambuco, Brasil)
FUNDING
Fundação para a Ciência e a Tecnologia (FCT), Portugal
European Research Council (ERC); European Commission
The following manuscripts have resulted form work carried out up to an including
2011: Sousa, Magalhães and Gordo 2011, Cost of resistance and the geometry
of adaptation Molecular Biology and Evolution; Trindade, Sousa and Gordo
Robustness in Antibiotic Resistance (submitted). Silva RF, Mendonça SC, Carvalho
LM, Reis AM, Gordo I, Trindade S, Dionisio F. PLoS Genet. 2011 Jul; 7(7):e1002181.
ADAPTATION WITHIN ECOSYSTEMS
Experimental evolution with bacteria presents us with the opportunity to directly
measure key parameters and to test theoretical predictions about the
genetic basis of adaptive evolution in increasingly complex ecosystems. As
Dobzansky pointed out “The greater the diversity of inhabitants in a territory,
the more adaptive opportunities exist in it.” The main goal of this research project
is to measure rates and effects of adaptive mutations, as well as patterns of
epistasis amongst beneficial mutations in different environments with different
strengths of abiotic versus biotic interactions. In this way the importance of
ecology is increasingly emphasized so as to understand its impact on the statistical
laws governing adaptation.
The following manuscripts have been completed: Trindade, Sousa and Gordo
(submitted), Robustness and Stress in Antibiotic Resistance; Gordo and Campos
(submitted), Evolution of clonal populations approaching a fitness peak; Batista,
Sousa, Bergman, Xavier, Demengeot and Gordo, Adaptation of Escherichia coli
in its natural ecosystem, and M Miskinyte, ML Bergman, I Caramalho, S Magalhães,
J Demengeot and I Gordo Rapid microbial adaptation to escape the sentinels
of innate immunity.
ADAPTATION OF COMMENSAL BACTERIA TO THE MAMMALIAN GUT
The conduction of this project will for the first time determine the dynamics
of adaptation of E. coli in mice bearing a normal immune system and a complex
microbiota and determine the importance of clonal interference during
adaptation in vivo. Next, it will determine the contribution of the microflora on
these dynamics. Finally, the possible double-edged contribution of the immune
system, an original hypothesis, will be formally tested. This work will also open
new avenues for the community and for the three groups involved. Future investigations
will likely address the nature of the mutations, the effect of specific
bacterial species and variants and the precise immune mechanism behind the
selective pressure. This project was started in 2011
IGC ANNUAL REPORT ‘11
RESEARCH GROUPS
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