PhD defence by Garazi Martin-Bideguren
Microbe-driven adaptation in vertebrates - Insights from common wall lizards (Podarcis muralis)
Garazi Martin-Bideguren will defend her PhD thesis on the 25th of June, Wednesday. The defence will take place in the CSS 18.01.11 auditorium at 9.30am. Garazi has carried out her thesis on lizard microbiomes at the Section for Hologenomics during the last three years, after two years of research assistant work in HoloFood.
Microbe-driven adaptation in vertebrates
Insights from common wall lizards (Podarcis muralis)
Supervisor: Associate Professor Antton Alberdi and Co-supervisor: Professor Tobias Uller
The current biodiversity crisis is accelerating environmental changes at an unprecedented rate,
placing increasing pressure on animals to adapt rapidly. In this context, phenotypic plasticity—the
ability of organisms to adjust their traits in response to environmental conditions—plays a crucial
role in short-term acclimation of vertebrates. Traditionally, phenotypic plasticity has been viewed as
the result of interactions between the host genome and the environment, however, evidence
indicates that the genomes of the associated gut microorganisms may also contribute to modulate
those phenotypes. In light of this, the microbe-driven adaptation hypothesis posits that gut
microorganisms may contribute significantly to host adaptability. Testing this hypothesis in
non-model wild organisms not only expands our knowledge of the relevance of microorganisms in
vertebrate ecology and evolution, but also carries important implications for animal conservation in
the face of climate change.
In this thesis, I explored the role of gut microbes in vertebrates’ adaptation to new environmental
conditions, using Podarcis muralis lizards as a study system. First, I addressed the existing body of
research on the microbe-driven adaptation hypothesis by conducting a quantitative synthesis of the
literature. I then examined the variation in the gut microbiota of wild P . muralis lizards across four
elevational transects in the Pyrenees mountain range, focusing on both taxonomic and functional
features. Following this, I conducted a captivity experiment involving wild Podarcis individuals from
two populations exposed to distinct environmental conditions. In this experiment, I performed
faecal microbiota manipulation and investigated its effects on the thermal physiology of the
reptiles. Finally, I explored the methodological details of the faecal microbiota transplantation
approach used in the captivity experiment.
Collectively, this thesis advances our understanding of host–microbiota interactions in lizards,
provides methodological insights into manipulating gut microbiota in non-model wild organisms,
and contributes valuable perspectives for further exploring the microbe-driven adaptation
hypothesis.