OMIA:002130-7994 : Coat colour, oculocutaneous albinism, OCA2-related in Astyanax mexicanus (Mexican tetra)

In other species: Rhesus monkey , dog , corn snake

Categories: Pigmentation phene

Links to possible relevant human trait(s) and/or gene(s) in OMIM: 203200 (trait) , 611409 (gene)

Links to relevant human diseases in MONDO:

Mendelian trait/disorder: yes

Mode of inheritance: Autosomal

Considered a defect: yes

Key variant known: yes

Year key variant first reported: 2006

Cross-species summary: Tyrosinase-positive oculocutaneous albinism (OCA, type II) is an autosomal recessive disorder in which the biosynthesis of melanin pigment is reduced in skin, hair, and eyes.

Species-specific description: This phene includes references to studies involving genetically modified organisms (GMO).

Mapping: Using microsatellite linkage mapping, Protas et al. (2006) mapped albinism in populations from two separate Mexican caves (Molino and Pachón; around 50 km apart) to the same location in linkage group 16. Subsequent complemetation testing indicated that "albinism in these two cave populations is caused by mutations in the same gene". Protas et al. (2006) then linkage mapped several comparative candidate pigmentation genes, and showed that one of these genes (Oca2) mapped to the albinism locus.

Molecular basis: By comparing cDNA sequence, Prosat et al. (2006) were able to show that albinism in the Molino cave population is due to a deletion of exon 21, and in the Pachón cave population is due to the deletion of most of exon 24.

Genetic engineering: Yes - in addition to the occurrence of natural variants, variants have been created artificially, e.g. by genetic engineering or gene editing
Have human generated variants been created, e.g. through genetic engineering and gene editing

Associated gene:

Symbol Description Species Chr Location OMIA gene details page Other Links
OCA2 Astyanax 5 NC_064412.1 (18569784..18425444) OCA2 Homologene, Ensembl , NCBI gene

Cite this entry

Nicholas, F. W., Tammen, I., & Sydney Informatics Hub. (2023). OMIA:002130-7994: Online Mendelian Inheritance in Animals (OMIA) [dataset].


Note: the references are listed in reverse chronological order (from the most recent year to the earliest year), and alphabetically by first author within a year.

2023 Moran, R.L., Richards, E.J., Ornelas-García, C.P., Gross, J.B., Donny, A., Wiese, J., Keene, A.C., Kowalko, J.E., Rohner, N., McGaugh, S.E. :
Selection-driven trait loss in independently evolved cavefish populations. Nat Commun 14:2557, 2023. Pubmed reference: 37137902. DOI: 10.1038/s41467-023-37909-8.
Sifuentes-Romero, I., Aviles, A.M., Carter, J.L., Chan-Pong, A., Clarke, A., Crotty, P., Engstrom, D., Meka, P., Perez, A., Perez, R., Phelan, C., Sharrard, T., Smirnova, M.I., Wade, A.J., Kowalko, J.E. :
Trait loss in evolution: What cavefish have taught us about mechanisms underlying eye regression. Integr Comp Biol 63:393-406, 2023. Pubmed reference: 37218721. DOI: 10.1093/icb/icad032.
2021 Borowsky, R. :
Evolution: The genetics of trait evolution in cavefish. Curr Biol 31:R1014-R1016, 2021. Pubmed reference: 34428412. DOI: 10.1016/j.cub.2021.06.016.
O'Gorman, M., Thakur, S., Imrie, G., Moran, R.L., Choy, S., Sifuentes-Romero, I., Bilandžija, H., Renner, K.J., Duboué, E., Rohner, N., McGaugh, S.E., Keene, A.C., Kowalko, J.E. :
Pleiotropic function of the oca2 gene underlies the evolution of sleep loss and albinism in cavefish. Curr Biol 31:3694-3701.e4, 2021. Pubmed reference: 34293332. DOI: 10.1016/j.cub.2021.06.077.
2018 Klaassen, H., Wang, Y., Adamski, K., Rohner, N., Kowalko, J.E. :
CRISPR mutagenesis confirms the role of oca2 in melanin pigmentation in Astyanax mexicanus. Dev Biol 441:313-318, 2018. Pubmed reference: 29555241. DOI: 10.1016/j.ydbio.2018.03.014.
2015 Ma, L., Jeffery, W.R., Essner, J.J., Kowalko, J.E. :
Genome editing using TALENs in blind Mexican Cavefish, Astyanax mexicanus. PLoS One 10:e0119370, 2015. Pubmed reference: 25774757. DOI: 10.1371/journal.pone.0119370.
2013 Bilandžija, H., Ma, L., Parkhurst, A., Jeffery, W.R. :
A potential benefit of albinism in Astyanax cavefish: downregulation of the oca2 gene increases tyrosine and catecholamine levels as an alternative to melanin synthesis. PLoS One 8:e80823, 2013. Pubmed reference: 24282555. DOI: 10.1371/journal.pone.0080823.
Gross, J.B., Wilkens, H. :
Albinism in phylogenetically and geographically distinct populations of Astyanax cavefish arises through the same loss-of-function Oca2 allele. Heredity (Edinb) 111:122-30, 2013. Pubmed reference: 23572122. DOI: 10.1038/hdy.2013.26.
2009 Gross, J.B., Borowsky, R., Tabin, C.J. :
A novel role for Mc1r in the parallel evolution of depigmentation in independent populations of the cavefish Astyanax mexicanus. PLoS Genet 5:e1000326, 2009. Pubmed reference: 19119422. DOI: 10.1371/journal.pgen.1000326.
Jeffery, W.R. :
Chapter 8. Evolution and development in the cavefish Astyanax. Curr Top Dev Biol 86:191-221, 2009. Pubmed reference: 19361694. DOI: 10.1016/S0070-2153(09)01008-4.
Jeffery, W.R. :
Regressive evolution in Astyanax cavefish. Annu Rev Genet 43:25-47, 2009. Pubmed reference: 19640230. DOI: 10.1146/annurev-genet-102108-134216.
2006 Protas, ME., Hersey, C., Kochanek, D., Zhou, Y., Wilkens, H., Jeffery, WR., Zon, LI., Borowsky, R., Tabin, CJ. :
Genetic analysis of cavefish reveals molecular convergence in the evolution of albinism. Nat Genet 38:107-11, 2006. Pubmed reference: 16341223. DOI: 10.1038/ng1700.
2002 Borowsky, R., Wilkens, H. :
Mapping a cave fish genome: polygenic systems and regressive evolution. J Hered 93:19-21, 2002. Pubmed reference: 12011170.
1969 Sadoglu, P., McKee, A. :
A second gene that affects eye and body color in Mexican blind cave fish. J Hered 60:10-4, 1969. Pubmed reference: 5798137.
1957 Şadoğlu, P. :
Mendelian inheritance in the hybrids between the Mexican blind cave fishes and their overground ancestor. Verh Dtsch Zool Ges Graz. :432-439, 1957.
1955 Şadoğlu, P. :
Mendelian gene for albinism in natural cave fish. Experientia 13:394–395, 1955.

Edit History

  • Created by Frank Nicholas on 12 Jun 2006
  • Changed by Frank Nicholas on 12 Dec 2011
  • Changed by Frank Nicholas on 21 Mar 2012
  • Changed by Frank Nicholas on 03 Oct 2014
  • Changed by Frank Nicholas on 11 Oct 2017
  • Changed by Imke Tammen2 on 26 Aug 2021
  • Changed by Imke Tammen2 on 28 Aug 2021
  • Changed by Imke Tammen2 on 18 Dec 2023