How do troglodite cave catfish get pale? Common mutations in cave fish.
Posted: 27 Jul 2018, 07:46
Espinasa, L., Robinson, J., & Espinasa, M. (2018). Mc1r gene in Astroblepus pholeter and Astyanax mexicanus: Convergent regressive evolution of pigmentation across cavefish species. Developmental Biology. Available online 19 July 2018
https://doi.org/10.1016/j.ydbio.2018.07.016
Highlights
https://doi.org/10.1016/j.ydbio.2018.07.016
Highlights
- For the first time, the molecular reasons for the development of a troglomorphic phenotype is being studies in the Stygobitic catfish , a depigmented fish found within some river caves in Ecuador.
- pholeter displays mutations in ultra-conserved areas of the pigment-controlling gene, Mc1r, that have been linked to pigment regulation in other organisms.
- Since cavefish also has mutations in this gene, it is thus concluded that Mc1r, a gene known to control pigment variation in many organisms, may be the target of cavernicole regressive evolution across species in different families of fish.
Abstract
Cave-adapted organisms are often characterized by a reduction in pigmentation, eyesight, and enhanced mechanosensory functions. Previous studies have described the genetic basis for a depigmented phenotype in multiple independent populations of the Blind Mexican Tetra, ; the reduction in melanin content (brown; Mc1r). At least seven wild populations express the brown phenotype. In three populations, there are two different coding sequence alterations affecting Mc1r and the remaining four populations show the accumulation of sequence mutations affecting the 5′ regulatory region. Thus, the Mc1r gene has been the repeated and independent location of mutations in Astyanax. As such, it would appear that this gene is a target during regressive evolution of cave adapted organisms. If this is the case, it would be expected that other cave adapted fish would have mutations in the same gene. We study here the stygobitic catfish Astroblepus pholeter, a depigmented fish found within some river caves in Ecuador. A. pholeter displays mutations in ultra-conserved areas of the pigment-controlling gene, Mc1r, that have been linked to pigment regulation in other organisms. It is thus concluded that Mc1r, a gene known to control pigment variation in many organisms, may be the target of cavernicole regressive evolution across species in different families of fish.
- Keywords: Astroblepus pholeter, , Astyanax, cave, catfish, Jumandi cave, troglobite, reduction in pigmentation, regressive evolution, OCA2Mc1r
