Meeting Abstract
Hypoxia is an important environmental pressure that likely drives novel adaptive solutions. To cope with this extreme condition, animals often evolve low-oxygen tolerance, or improve oxygen retrieval from their habitat. The blind Mexican cavefish, Astyanax mexicanus, inhabits an expansive cave network within the Sierra de El Abra region of northeastern Mexico. The caves in this system are geographically isolated from one another, and demonstrate variably low levels of dissolved oxygen within the subterranean pools. These cavefish, alongside extant ‘ancestral’ surface morphs, enable powerful comparisons to determine how they thrive under hypoxic conditions. We evaluated hypoxia-tolerance in multiple, independent cave populations at the protein, cellular and genetic levels. We discovered that phylogenetically older populations display higher tolerance to hypoxia compared to phylogenetically younger (and hybrid) populations. These differences include alterations in hemoglobin concentration, as well as higher expression of a cohort of hemoglobin genes. This work provides insight to the genetic changes mediated hypoxia tolerance in blind cavefish, and showcases the diverse genetic and cellular strategies of adaptation among independent cavefish populations of the Sierra de El Abra.
