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Cellular and genetic bases of neural circuits evolution

Project description

Flies may not speak or have noses but they can tell us a lot about olfactory evolution

Evolution is the process by which populations of organisms change over time due to genetic variations. It is relatively straightforward to grasp the significance of evolution with regard to structural changes such as fins becoming feet, and even functional implications such as being able to walk on land. However, it is more complicated to grasp how evolutionary structural changes in the brain affect context-dependent sensory-evoked behaviours, many of which are critical to reproduction and survival. The EU-funded EvolutioNeuroCircuit project is hot on the trail of answers to these mysteries. The team is studying the developing olfactory system of four different species of the fly Drosophila melanogaster with evolutionarily different odour-evoked behaviours. The sweet smell of success is in the air.

Objective

Sensory systems encode the world around us to produce context-dependent appropriate behaviours. However, we know little about the way new sensory evoked behaviours arise as neural circuits are re-shaped during evolution. Tackling this question requires a deep understanding of the circuits underlying specific behaviours and integration of this knowledge with tools from other fields, including evolutionary and developmental biology. Recent technological advancements on neural circuit interrogation and genome editing have put progress on this fundamental biological question within reach.
The olfactory system of the larval stage of the fly Drosophila melanogaster and related species is an ideal model for investigating these questions because (i) D. melanogaster has pioneered both the fields of population genetics and neurogenetics and (ii) its olfactory system is one of the best-characterised neural circuits. We will address the question of how olfactory circuits evolve by studying four species with divergent odour-guided behaviours through the following multidisciplinary aims:
1. Which olfactory pathways are targeted in the evolution of ecological specialisation? – Combining high-throughput behavioural assays, optogenetics and calcium imaging in the larva of all four species we will determine whether/which olfactory pathways have switched valences or sensitivity.
2. How have central neural circuits diverged? – We will address this question at unprecedented resolution through whole-brain calcium imaging and serial electron microscopy reconstruction.
3. What are the molecular and genetic bases of neural circuits rewiring during evolution? – Using transcriptomic profiling we will identify differentially expressed genes in conserved and divergent circuits across species, and functionally probe selected candidates to establish causality.
4. How do evolutionary forces shape olfactory circuits? – We will investigate this question using field studies and population genetics

Host institution

THE FRANCIS CRICK INSTITUTE LIMITED
Net EU contribution
€ 1 312 500,00
Address
1 MIDLAND ROAD
NW1 1AT London
United Kingdom

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Region
London Inner London — West Camden and City of London
Activity type
Research Organisations
Links
Total cost
€ 1 312 500,00

Beneficiaries (1)