The MC1R gene in the guppy (Poecilia reticulata): Genotypic and phenotypic polymorphisms
1 Department of Ecology and Evolutionary Biology, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
2 Department of Developmental Biology and Neuroscience, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
3 Department of Biology, Faculty of Science, Yamagata University, 1-4-12 Kojirakawa, Yamagata-City 990-8560, Japan
4 Evolutionary Biology Group, Department of Biological Sciences, University of Hull, Hull, HU6 7RX, UK
5 Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, 1266 Tamura-cho, Nagahama, Shiga 526-0829, Japan
6 School of Environmental Sciences, University of East Anglia, Norwich NR4 7TJ, UK
BMC Research Notes 2011, 4:31 doi:10.1186/1756-0500-4-31Published: 4 February 2011
The guppy (Poecilia reticulata) is an important model organism for studying sexual selection; male guppies have complex and conspicuous pigmentation, and female guppies exhibit preferences for males with specific color spots. Understanding the genetic basis underlying pigmentation variation in the guppy is important for exploring the factors causing the maintenance of color polymorphism in wild populations.
We focused on the melanic black pigmentation of guppies, and examined genetic variations in the melanocortin 1 receptor (MC1R) gene because variation in this gene is known to contribute to polymorphism of melanin pigmentation in several animal species. The complete coding sequence of the guppy MC1R gene was determined, and two different MC1R alleles (963 and 969 bp) were found in wild populations. Ornamental strain guppies with a 963-bp MC1R tended to show less black pigmentation than those with a 969-bp MC1R, although the association between MC1R genotype and black pigmentation disappeared in the F2 offspring.
The guppy MC1R gene showed variation in the five wild Trinidadian populations we examined, and these populations also differed in terms of allele frequencies. We identified a significant association between black pigmentation and MC1R genotype in fish obtained from aquarium shops. However, the results from F2 families suggest that there are other genes that modify the effects of the MC1R gene.