A mutation in the enzyme monoamine oxidase explains part of the Astyanax cavefish behavioural syndrome.
We use Astyanax mexicanus, a single species with surface-dwelling forms (SF) and blind de-pigmented cave forms (CF), to study mechanisms underlying the evolution of brain and behaviour. In CF, the origin of changes in complex motivated behaviours (social, feeding, sleeping, exploratory) is unknown. Here we find a hyper-aminergic phenotype in CF brains, including high levels and neurotransmission indexes for serotonin, dopamine and noradrenaline, and low monoamine oxidase (MAO) activity. Although MAO expression is unchanged in CF, a pro106leu mutation is identified in the MAO coding sequence. This mutation is responsible for low MAO activity and high serotonin neurotransmission index in CF brains. We find the same mutated allele in several natural CF populations, some being independently evolved. Such occurrence of the same allele in several caves may suggest that low MAO activity is advantageous for cave life. These results provide a genetic basis for several aspects of the cavefish 'behavioural syndrome'.
DECA Group, UPR3294 CNRS, 1, avenue de la Terrasse, 91198 Gif sur Yvette, France.
Yannick
Y
Elipot
DECA Group, UPR3294 CNRS, 1, avenue de la Terrasse, 91198 Gif sur Yvette, France.
Hélène
H
Hinaux
Service Biochimie et Biologie Moléculaire U942 INSERM, Hôpital Lariboisière, 41 boulevard de la Chapelle, 75475 Paris, France.
Jacques
J
Callebert
Service Biochimie et Biologie Moléculaire U942 INSERM, Hôpital Lariboisière, 41 boulevard de la Chapelle, 75475 Paris, France.
Jean-Marie
JM
Launay
DECA Group, UPR3294 CNRS, 1, avenue de la Terrasse, 91198 Gif sur Yvette, France.
Maryline
M
Blin
DECA Group, UPR3294 CNRS, 1, avenue de la Terrasse, 91198 Gif sur Yvette, France.
Sylvie
S
Rétaux
D000818:Animals; D001921:Brain / Q000378:metabolism*; D060125:Characiformes / Q000378:metabolism*; D004298:Dopamine / Q000378:metabolism; D008995:Monoamine Oxidase / Q000378:metabolism*; D009638:Norepinephrine / Q000378:metabolism; D012701:Serotonin / Q000378:metabolism
D012701:Serotonin; D008995:Monoamine Oxidase; D004298:Dopamine; D009638:Norepinephrine