Circadian rhythms in Mexican blind cavefish Astyanax mexicanus in the lab and in the field.
Biological clocks have evolved as an adaptation to life on a rhythmic planet, synchronising physiological processes to the environmental light-dark cycle. Here we examine circadian clock function in Mexican blind cavefish Astyanax mexicanus and its surface counterpart. In the lab, adult surface fish show robust circadian rhythms in per1, which are retained in cave populations, but with substantial alterations. These changes may be due to increased levels of light-inducible genes in cavefish, including clock repressor per2. From a molecular standpoint, cavefish appear as if they experience 'constant light' rather than perpetual darkness. Micos River samples show similar per1 oscillations to those in the lab. However, data from Chica Cave shows complete repression of clock function, while expression of several light-responsive genes is raised, including DNA repair genes. We propose that altered expression of light-inducible genes provides a selective advantage to cavefish at the expense of a damped circadian oscillator.
1] Centre for Cell and Molecular Dynamics, Department of Cell and Developmental Biology, University College London, 21 University Street, London WC1E 6DE, UK [2].
Andrew
A
Beale
Christophe
C
Guibal
T Katherine
TK
Tamai
Linda
L
Klotz
Sophie
S
Cowen
Elodie
E
Peyric
Víctor H
VH
Reynoso
Yoshiyuki
Y
Yamamoto
David
D
Whitmore
D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D059552:Caves; D060126:Characidae / Q000235:genetics / Q000502:physiology*; D002940:Circadian Rhythm / Q000502:physiology*; D004260:DNA Repair / Q000235:genetics / Q000502:physiology; D017753:Ecosystem; D005786:Gene Expression Regulation / Q000528:radiation effects*; D008027:Light; D008800:Mexico; D008969:Molecular Sequence Data; D056950:Period Circadian Proteins / Q000235:genetics / Q000378:metabolism
D056950:Period Circadian Proteins