Conference Paper
Adaptation through changes of behavioral and morphological traits in Mexican Cavefish
Yoshizawa, M., Settle, A., Macaspac, C., Fernandes, V. Yoshida, M. and Keene, A.
Record Number:
3906
Year:
2016
Abstract:
Cave animals have been evolving under no visual information and with different food sources from surface environment. Accordingly, cave animal evolved multiple traits including enhanced sensory system and shifted physiology in nervous systems. Astyanax mexicanus is a model cave animal with sighted surface-dwelling and blind cave-dwelling forms, whose surface ancestors were separated in caves 1 - 5 million years ago. Here we describe multiple cave associated behaviors, adaptation, and their sensory basis. First, cavefish (but not many surface fish) exhibit vibration attraction behavior (VAB), or the ability to swim toward the source of a water disturbance in darkness. Individual fish expressing this VAB showed a significant advantage in foraging comparing with the fish without VAB. VAB is mediated by mechanosensory superficial neuromasts (SN), which are enhanced in number and sensitivity in cavefish. Endothelin signaling regulates the cranial SN number through the intramembranous bone formation. The treatment of Endothelin inhibitor, BQ123, in one month old-surface fish, successfully enhanced the cranial SN number but didn't increase VAB level, suggesting that the sensory enhancement may be not enough for the evolution of adaptive foraging behavior. Secondly, cavefish lost their sleep and gained hyper activity through evolutionary process. The treatment of human psychiatric drugs, Fluoxetine (selective serotonin reuptake inhibitor) and Clozapine (inhibitor for multiple serotonin and dopamine receptors) but not Naltrexone (inhibitor for opioid receptors), significantly recovered sleep and reduced the activity in cavefish, suggesting that, in certain parts, cavefish behavior can be based on the overlapped neural pathways with human patients. Finally, we are using genotyping-by-sequencing technology to genome wide association mapping for VAB, SN, sleep and hyper activity. We will discuss some candidate genes for these traits, which will provide the bases of a detailed evolutionary example for cave-type behaviors.
Times Cited:
1
Conference Name:
23rd International Conference on Subterranean Biology
Conference Year:
2016
Conference Location:
2016
Conference Location:
2016
Relevent Species: