The blind morph of Astyanax fasciatus (Pisces: Characidae) has been more thoroughly studied than any other cave inhabiting organism. Most studies of A. fasciatus have used individuals from different caves of the Sierra de El Abra, Mexico, and have assumed that each population independently evolved to live in the cave environment. We analyzed the relationships among several cave populations that delineate the Sierra de El Abra using RAPD markers. The results indicate that all cave populations are more closely related to one another than they are to the surface populations. This suggests that present day cave populations derived from a common ancestral stock, most likely due to a single colonization event, or alternatively, that strong gene flow among cave populations has occurred, raising precaution against considering each cave population as independent.
- Cave colonization
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics
- Aquatic Science