Has the Blind Mexican Cave Fish Lost its Rhythm?
Circadian rhythms are common to nearly all organisms and are typically regulated by photoperiod. As animals lose the ability to sense photoperiod, such as losing eyes via an epigenetic change, it may become impediment for them to possess a circadian rhythm. In this study, we aimed to address whether a genetic basis for circadian rhythm is retained in an eyeless cave fish, Astyanax mexicanus. We completed search for the circadian rhythm sequences of Astyanax mexicanus using an online genomic database, then generated an alignment of the gene homologs to model fish species. Putative proteins were annotated on the alignment, and similarity software will be used to find percent similarity of the proteins. Finally, a phylogenetic tree will be estimated. We conclude that Astyanax mexicanus has lost or mutated some of its DNA with disuse and lack of a need for a correction mechanism over time