Structure and function of sensory Ionotropic Receptors
Since our discovery in 2009 of Ionotropic Receptors (IRs) – a subclade of the ionotropic glutamate receptor superfamily of ligand-gated ion channels – as a novel family of insect olfactory receptors, we and others have shown that these proteins have evolved diverse roles in olfaction, gustation, hygrosensation and thermosensation across insects. IRs form heteromeric complexes of “tuning” receptors, which define stimulus specificity, and one or more co-receptor subunits, which function in subcellular trafficking and signalling. We are currently developing in vivo, in vitro and in silico approaches to understand the mechanisms and evolution of ligand-recognition, heteromeric complex assembly and channel gating.
Evolutionary neurodevelopmental biology of olfactory circuits
Olfactory pathways are one of the most dynamically evolving parts of the nervous system: animals frequently acquire (and discard) olfactory receptors, circuits and odour-evoked behaviours with the ever-changing landscape of stimuli in their environment. The evolutionary flexibility of olfactory systems is reflected in their modular organisation: in insects (as in vertebrates), most individual olfactory sensory neurons (OSNs) express just one olfactory receptor gene, and the axons of OSNs expressing the same receptor converge on discrete regions of neuropil (glomeruli) within the primary olfactory centre, where they synapse with second-order neurons. The numbers of olfactory receptors vary widely across species, with concordant diversity in the number and organisation of OSNs and glomeruli in the brain.
Using molecular genetic, single-cell sequencing and circuit tracing approaches in the D. melanogaster peripheral olfactory system, we are studying the mechanisms and evolution of (i) neuronal lineage specification, (ii) olfactory receptors’ singular expression patterns, (iii) how novel populations of OSNs arise through changes in patterns of neurogenesis and developmental programmed cell death, and (iv) how OSN populations are segregated to distinct glomeruli to form unique sensory channels in the brain. The mechanisms and molecules we characterise are likely to be relevant for understanding circuit formation and evolution in other brain regions and species.
Drosophila sechellia: a novel neurogenetic model
How animals’ extraordinarily diverse behaviours have evolved is unknown. Relating interspecific behavioural differences to anatomical or physiological distinctions in neural circuits, and causal genetic variation, offers a powerful approach to inform how nervous systems develop, function and change. We are establishing a new model neurogenetic system, Drosophila sechellia, an island endemic that is closely related to D. melanogaster and D. simulans. While D. sechellia retains global genomic and superficial morphological similarity to its cosmopolitan generalist cousins, this species has adapted to a unique ecological niche, using Morinda fruit as a sole host for feeding and breeding. This work, which now takes our lab beyond the olfactory system, is being developed through three main aims:
(i) Establishment of a D. sechellia (neuro)genetic toolkit: we are building essential genetic reagents for generation and maintenance of animals of desired genotypes, for neurogenetic manipulations, and for recombination mapping-based approaches.
(ii) Behavioural, neuroanatomical and molecular phenomics: systematic comparison of D. sechellia, D. simulans and D. melanogaster for their behaviours, their neuroanatomy and their neuro-molecular expression properties should reveal how D. sechellia has adapted to its niche, and will provide multiple entry-points to relate molecular, neuronal and behavioural differences between these species.
(iii) Defining the genetic basis and functional significance of neuronal adaptations in D. sechellia: through high-resolution quantitative trait mapping and interspecific allele swap approaches, we aim to identify the causal genetic changes underlying neural adaptations in D. sechellia, and their physiological and behavioural significance.
Advanced search is available through Serval
Publications can be managed by accessing Serval via MyUnil
Quelques articles/emissions sur notre recherche - Some articles/broadcasts about our research
Understanding the fruit fly's nose (SNF/Latsis) (en anglais, sous-titré en français)
Une mouche alliée de la science (RTS - CQFD)
What fruit flies can teach us about the science of smell (Podcast at swissinfo.ch)
Sa majesté des mouches (Le Temps)
Rencontre avec Richard Benton (RTS - CQFD)
Im Kopf von Fruchtfliegen - Migros Magazin (auf deutsch)
The wisdom of the fly crowds (Ed Yong/National Geographic)
The world's first true aphrodisiac (NBC News)
An ant’s kiss may hide a sneaky form of communication - a comment in Science on our paper on trophallaxis and chemical communication in social insects; see also the Daily Mail and Wire