Why cavefish are blind.
Some fish exist as eyed, surface-dwelling and eyeless, cave-dwelling forms. The developmental processes that cause eye degeneration in different populations of Astyanax cavefish are similar. Although small optic primordia start to form, apoptosis of lens cells triggers developmental arrest and degeneration of the eyes. Degeneration has been linked to reduced expression of the transcription factor Pax6 in the anterior embryonic midline and optic primordia. Recently, Yamamoto and colleagues reported that increased expression of the diffusible morphogen Sonic hedgehog (Shh) at the embryonic midline of cavefish reduces pax6 expression and increases expression of Shh-regulated genes, which might confer selective advantages for life in caves.
Tian
Natasha M M-L
NM
Genes and Development Group, Centre for Integrative Physiology, Edinburgh, UK.
Price
David J
DJ
D000818:Animals; D001766:Blindness; D005136:Eye Proteins / Q000502:physiology; D005399:Fishes / Q000196:embryology / Q000502:physiology*; D053823:Hedgehog Proteins; D018398:Homeodomain Proteins / Q000502:physiology; D009024:Morphogenesis; D000071841:PAX6 Transcription Factor; D051761:Paired Box Transcription Factors; D012097:Repressor Proteins; D015534:Trans-Activators / Q000502:physiology
D005136:Eye Proteins; D053823:Hedgehog Proteins; D018398:Homeodomain Proteins; D000071841:PAX6 Transcription Factor; D051761:Paired Box Transcription Factors; D012097:Repressor Proteins; D015534:Trans-Activators