Open AccessConvergent evolution of the cavefish Astyanax (Characidae, Teleostei): genetic evidence from reduced eye‐size and pigmentation
Author(s) -
WILKENS HORST,
STRECKER ULRIKE
Publication year - 2003
Publication title -
biological journal of the linnean society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.906
H-Index - 112
eISSN - 1095-8312
pISSN - 0024-4066
DOI - 10.1111/j.1095-8312.2003.00230.x
Subject(s) - characidae , biology , teleostei , cave , convergent evolution , most recent common ancestor , evolutionary biology , ancestor , myr , molecular evolution , gene , fish <actinopterygii> , zoology , genetics , phylogenetics , ecology , genome , fishery , history , archaeology
More than 20 populations of the cave‐dwelling characid Astyanax occur within a restricted karst area in Mexico. The fish possess reduced eyes without lenses and visual cells. It is still an open question as to whether this condition evolved convergently after multiple entries of the surface ancestor into the different caves or whether a single cave ancestor, already characterized by reduced eyes, spread secondarily within them. In the crosses between specific populations, specimens appear that deviate considerably from those of the parents. They possess larger and better‐developed eyes with histologically intact lenses and visual cells; they thus have the structural potential for vision. This indicates that in different cave populations, different mutations in the eye gene system have occurred. In cases where these non‐functional rudimentary genes are recombined in hybrid specimens, gene expression may be restored. This is the result of separate evolution of several Astyanax cave populations. © 2003 The Linnean Society of London, Biological Journal of the Linnean Society, 2003, 80 , 545−554.