Original Research ARTICLE

Front. Genet., 25 January 2013 | http://dx.doi.org/10.3389/fgene.2013.00006

Melanocortin receptor 1 and black pigmentation in the Japanese ornamental carp (Cyprinus carpio var. Koi)

Ido Bar, Ethan Kaddar, Ariel Velan and Lior David*
  • Department of Animal Sciences, R. H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel

Colors and their patterns are fascinating phenotypes with great importance for fitness under natural conditions. For this reason and because pigmentation is associated with diseases, much research was devoted to study the genetics of pigmentation in animals. Considerable contribution to our understanding of color phenotypes was made by studies in domesticated animals that exhibit dazzling variation in color traits. Koi strains, the ornamental variants of the common carp, are a striking example for color variability that was selected by man during a very short period on an evolutionary timescale. Among several pigmentation genes, genetic variation in Melanocrtin receptor 1 was repeatedly associated with dark pigmentation phenotypes in numerous animals. In this study, we cloned Melanocrtin receptor 1 from the common carp. We found that alleles of the gene were not associated with the development of black color in Koi. However, the mRNA expression levels of the gene were higher during dark pigmentation development in larvae and in dark pigmented tissues of adult fish, suggesting that variation in the regulation of the gene is associated with black color in Koi. These regulatory differences are reflected in both the timing of the dark-pigmentation development and the different mode of inheritance of the two black patterns associated with them. Identifying the genetic basis of color and color patterns in Koi will promote the production of this valuable ornamental fish. Furthermore, given the rich variety of colors and patterns, Koi serves as a good model to unravel pigmentation genes and their phenotypic effects and by that to improve our understanding of the genetic basis of colors also in natural populations.

Keywords: pigmentation development, melanophore, larva, fish, color, mc1r

Citation: Bar I, Kaddar E, Velan A and David L (2013) Melanocortin receptor 1 and black pigmentation in the Japanese ornamental carp (Cyprinus carpio var. Koi). Front. Gene. 4:6. doi: 10.3389/fgene.2013.00006

Received: 21 November 2012; Accepted: 08 January 2013;
Published online: 25 January 2013.

Edited by:

Peng Xu, Chinese Academy of Fishery Sciences, China

Reviewed by:

Gen Hua Yue, National University of Singapore, Singapore
Yang Zhang, Texas A&M University, USA

Copyright © 2013 Bar, Kaddar, Velan and David. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in other forums, provided the original authors and source are credited and subject to any copyright notices concerning any third-party graphics etc.

*Correspondence: Lior David, Department of Animal Sciences, R. H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, PO Box 12, Rehovot 76100, Israel. e-mail: lior.david@mail.huji.ac.il

Present address: Ido Bar, Aquaculture Biotechnology, GeneCology Research Group, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydore DC, QLD, Australia.