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How is adaptation shaped by interactions between abiotic and biotic factors
In my current position, I am investigating the impact of interspecific interactions and cadmium pollution on the phenotypic and genomic changes during adaptation. For that I am using experimental evolution populations of T. urticae and T. evansi adapting alone or together to heterogeneous environments. By measuring eco-evolutionary responses at several biological scales (genes, phenotypes, communities) I aim to disentangle the impact of adaptation and ecological interactions on the ability of species to persist, colonize and invade new environments. |
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Tug of war between history, chance and selection during adaptation to new environments
The ability to respond to new environmental challenges is critical to survival. A major player in the adaptive process is natural selection, as it is one of the strongest driving forces in genetic or phenotypic changes in populations. However, other players, such as genetic drift and historical differentiation are often overlooked. During my PhD, with Prof. Margarida Matos and Mauro Santos, I focused on quantifying the importance of history, chance and selection in the adaptive process at several levels. For that I used a very simple scenario with Drosophila subobscura populations adapting to the laboratory environment, using experimental evolution to characterise the phenotypic and karyotypic trajectories in real time. Currently I am studying how spider mites adapt to cadmium in presence or absence of competitors (see more below). |
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Predictability and repeatability of evolution is contingent on time and biological level studied
Fitness landscapes are a powerful tool to visualize and study this problem. In fact, during my first postdoc at Dr. Claudia Bank's lab, I used a combination of theoretical modelling and statistical analyses of experimental data to investigate how changing environments affected the evolutionary paths available and the potential for adaptation. Namely, I demonstrated that synonymous mutations, usually considered neutral in population genetics, can impact adaptation to new environments by opening new evolutionary paths in more stressful environments. Finally, I am also working on quantifying the predictability and repeatability of adaptive evolution in Drosophila. Together with Margarida Matos' team, we showed that longer-term patterns of convergence can be obtained from transient periods of divergence, illustrating the dangers of using short-term evolution patterns to predict long-term evolution. |
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Distribution of fitness effects of new mutations is (not always) environment-dependent.
I have also investigated how environmental changes affect the distribution of fitness effects of new mutations and the adaptive potential of yeast populations using Hsp90. In collaboration with Dan Bolon’s team we observed that mutations that were robust to environmental changes were also those present in Hsp90 natural sequence. This suggests that in the long-term, selection purges mutations that are sensitive to fluctuating environments, leading to robustness under a variety of conditions. Furthermore, we also investigated the adaptive potential of Hsp90’s middle domain (which is involved in client binding and protein folding) under different environmental stresses. Here we observed that deleterious mutations showed a similar signal across environmental stresses, implying that potential costs of adaptation are not pervasive. Moreover, we observed that most beneficial mutations were only present in specific environments, and were potentially involved in changing Hsp90's clients. |
Eco-evolutionary feedbacks during adaptation |
How do abiotic and biotic interactions shape adaptation and the probability of coexistence
In my second postdoc I investigated the role of interspecific interactions during adaptation to metal pollution, using experimental evolution (as part of the team of COMPCON - consolidator grant attributed to Prof. Sara Magalhães). For that I started to work with Tetranychus urticae and T. evansi populations co-evolving on tomato plants exposed to high and low cadmium concentrations. My focus was to understand how adaptation to a new stress, in the presence and absence of a competitor, shaped the probability of coexistence between competing species and how it affects the potential to respond to new environmental challenges. |