Astyanax mexicanus Transcriptome or Gene expression
Astyanax provides a model for the retinal degeneration diseases of old age. Some populations of the Mexican tetra (Astyanax mexicanus) are blind cavefish that inhabit perpetually dark caves in Mexico. Living in environments devoid of light, Astyanax have evolved impaired vision and pigment loss by genetic drift or natural selection. Other populations of the Mexican tetra inhabit rivers and streams of northern Mexico and the southern US; these surface populations have normal eyes and dark pigment cells in their skin, thus providing a ''wild-type control'' for the ''evolutionary mutant'' cavefish. This species thus provides an ideal opportunity to study the genetic basis of retinal degeneration.