Dr. Giulia Zancolli

I’m an ecologist by training, an evolutionary biologist by trade rapidly evolving into an Evo-Devo scientist.

When I started doing research, I was fascinated by the interaction between the environment and organisms at different levels, from species distribution to phenotypic and genetic diversity, and their ecological drivers. To be honest, as many students of the Natural Sciences, I hoped to travel to exotic places, like the famous naturalist explorers of the 19th century, and study the incredible biodiversity of those ecosystems. With that goal in mind, I obtained an Excellence Initiative Fellowship from the German Research Foundation (DFG) and designed my PhD project to make it happen! That’s how I found myself studying the amphibian community of Mount Kilimanjaro in Tanzania.
After chasing frogs up and down the roof of Africa, I joined Wolfgang Wüster’s lab to investigate the causes and mechanisms of variation in venom composition in the Mohave rattlesnake (Crotalus scutulatus). Which is how I discovered the wonderful world of animal venoms!
Current project
Venomous animals are found throughout the entire tree of life, where organisms have independently evolved sophisticated apparatuses to produce and deliver potent biochemical weapons. There are more than 200,000 known venomous animal species and, unsurprisingly, they have been subject of public fascination throughout human history for good reason - small and often fragile-looking animals are capable of injecting complex cocktails of bioactive molecules that can result in devastating damage and often death. The evolutionary acquisition of venom therefore remodels the predator-prey interaction from a physical to a biochemical battle enabling small animals to defeat larger organisms. Acquiring such weaponry involves evolving a “factory” for venom production including, for instance, an exocrine gland, ducts and muscular bulbs, as well as a delivery system such as fangs, stingers, harpoons, forcipules among others.
This raises the question: how did animals repeatedly evolve such a successful trait? Within the framework of my Marie Curie project “EVER – Evolution of Venom Regulation” at DEE, I will uncover the secrets of one of nature’s most remarkable examples of convergent evolution: VENOM.

Venomous animals offer an incredible opportunity to investigate the regulation and development of cell and tissue novelty, and to test whether the underlying molecular mechanisms are similar across taxa, thus to contribute to a more general and predictive formulation of evolutionary theories.


(a) Does parallelism underlie the evolutionary convergence of innovative traits?


The recent omics revolution has generated an explosion of venom-gland transcriptomes mainly for biodiscovery and drug development. However, the mechanisms underlying the emergence and regulatory evolution of venom remains unknown. In this first part of the project, I compare transcriptomes of non-homologous venom glands across the major lineages of the animal kingdom to shed light on the processes underpinning the repeated evolution of the venom apparatus.


(b) What makes the venom gland unique?


Secondly, to understand the mechanisms responsible for the evolution of a derived novel structure, I focus on one lineage which includes organisms with and without venom. The study system of choice is the Neogastropoda, an order of marine predatory molluscs that includes the Conoidea (cone snails), characterized by a well-developed venom apparatus, and two other non-venomous clades - the Muricoidea, characterized by the gland of Leiblein, and the Cancellarioidea which possess a mid-oesophageal gland. For this project, I collaborate with Maria Vittoria Modica (Stazione Zoologica Anton Dohrn, Napoli), Sébastien Dutertre (Université de Montpellier), Nicolas Puillandre (Muséum National d'Histoire Naturelle Paris), Alexander Fedosov and Yuri Kantor (Russian Academy of Sciences), and the MNHN New Caledonia expedition (http://www.nouvellecaledonie.laplaneterevisitee.org/fr). By means of comparative transcriptomics of the venom gland and its homologous non-venom structures, I test if novel genes or the differential orchestration of pre-existing genes contribute to the evolution of the venom system, hence which mechanisms underpin the regulatory evolution of innovative traits.


(c) Is the expression pattern of novel cells inherited from the tissue of origin?


Cone snails deploy different sets of toxins for defense or predation. These toxins are differentially expressed and synthesized along the venom duct, with defense-evoked venom produced in the proximal region (P) whereas predation-evoked toxins are synthetized in the distal region (D). Structural differences are also observed along the venom duct. In this last part of the project, I aim to explore the molecular mechanisms responsible for the evolution of progressively derived cell types by analysing gene expression patterns between structurally and functionally different regions along the venom duct.

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