Journal Article
Reduced oxygen as an environmental pressure in the evolution of the blind Mexican cavefish
Boggs, T. and Gross, J.
Record Number:
5160
Year:
2021
Journal:
Diversity
Volume:
13(1), 26
Abstract:
Abstract: Extreme environmental features can drive the evolution of extreme phenotypes. Over the
course of evolution, certain environmental changes may be so drastic that they lead to extinction.
Conversely, if an organism adapts to harsh environmental changes, the adaptations may permit
expansion of a novel niche. The interaction between environmental stressors and adaptive changes is
well-illustrated by the blind Mexican cavefish, Astyanax mexicanus, which has recurrently adapted to
the stark subterranean environment. The transition from terrestrial rivers and streams (occupied by
extant surface morphs of the same species) to the cave has been accompanied by the resorption of
eyes, diminished pigmentation and reduced metabolism in cave-dwelling morphs. The principal
features of caves most often associated with evolution of these common cave features are the absence
of light and limited nutrition. However, a putatively essential cave feature that has received less
attention is the frequently low concentration of oxygen within natural karst environments. Here, we
review the potential role of limited oxygen as a critical environmental feature of caves in the Sierra
de El Abra. Additionally, we review evidence that Astyanax cavefish may have evolved adaptive
features enabling them to thrive in lower oxygen compared to their surface-dwelling counterparts.
Keywords: cavefish; dissolved oxygen; cave evolution; Astyanax mexicanus; Sierra de El Abra
Times Cited:
1
Relevent Species: