Conference Paper
Mechanisms underlying the evolution of olfactory capacities in blind cavefish
Retaux, S., Bibliowicz, J., Blin, M., Elipot, Y., Espinasa, L., Hinaux, H. and Tine, E.
Record Number:
3245
Year:
2017
Journal:
AIM 2017
Abstract:
We use A. mexicanus cavefish to understand developmental,
genetic and cellular mechanisms involved in brain and behavioral evolution. We have particularly
focused on the evolution of the olfactory sensory system, by a comparative approach at several
levels between cavefish and their surface-dwelling conspecifics.
First, we have assessed the olfactory capabilities of larvae and adults of the two Astyanax morphs.
Experiments performed in the lab in controlled conditions and using amino-acids as olfactory cues
show that Pachón cavefish have a much better olfactory discrimination threshold than surface fish.
Experiments performed inside the Subterráneo cave (Mexico) show that cave morphs strongly
respond to food-related olfactory cues and also to low concentrations of amino-acids. This suggests
that increased olfactory capacities have evolved independently in two caves.
In search for the origins of the outstanding olfactory capacities of cavefish, we have then compared
the development and the neuroanatomy of the olfactory epithelium/organ in Pachón embryos and
juveniles, we have manipulated its development, and we have tested the impact of the lack of
vision on olfactory capabilities. The results suggest that the size and the neuronal composition of
the olfactory epithelium, as well as some degree of developmental plasticity of the olfactory system
are responsible for the excellent cavefish olfaction.
Such a change in the cavefish olfactory sensory system can probably be considered as adaptive in
the extreme dark environment where cavefish live.
Times Cited:
1
Relevent Species: