Table 1.
Candidate genes that have been shown to influence melanin-based color patterns in mammals and/or bird model species
| Locus | Chromosome | Expressed in | Physiological roles | Involvement in polymorphism | Pleiotropic effects | References |
|---|---|---|---|---|---|---|
| Agouti | 20 | Dermis, adipose tissues, gonads, heart, liver, muscles | Interacts with MC1R and allows to switch from eumelanin to phaeomelanin production. Interacts with other melanocortin receptors involved in a range of physiological aspects. | Melanic variations in Peromyscus mice. Responsible for the yellow variants in quail and chicken. | + | Minvielle et al. (2007), Hiragaki et al. (2008), Nadeau et al. (2008), Kingsley et al. (2009) |
| Corin | 4 | Dermal papilla, heart | Serine protease expressed in the heart and in dermal papilla. Involved in regulating blood pressure and inhibits Agouti action on MC1R. | Melanic variations in Peromyscus mice. Limits the extent of phaeomelanic band in mice. | + | Yan et al. (1999), Enshell-Seijffers et al. (2008), Manceau et al. (2010) |
| DCT | 1 | Melanocyte | Involved in synthesis of melanin from l-dopaquinone | Responsible for the slaty phenotype in mice | − | Jackson et al. (1992) |
| POMC | 3 | Brain, immune cells, gastro- intestinal tract, dermis, adrenal glands, thyroid, pancreas | Interacts with MC1R and allows to switch to eumelanin production. Interacts with other melanocortin receptors involved in a range of physiological aspects. | KO responsible for obese and yellow mice. Variations in melanocortin levels observed between tawny owls morphs. | ++ | Yaswen et al. (1999), Roulin et al. (2011) |
| SLC24A5 | 10 | Melanocyte | Cation exchanger involved in migration of melanosomes toward keratinocytes | Dilution of pigments in humans, chicken and zebra fish. Down regulated in yellow quails. | − | Lamason et al. (2005), Nadeau et al. (2008) |
| TYR | 1 | Melanocyte | Involved in synthesis of dopaquinone from tyrosine | Responsible for the recessive white phenotype in chicken | − | Sato et al. (2007) |
| TYRP1 | Z | Melanocyte | Involved in synthesis of melanin from l-dopaquinone | Responsible for the roux phenotype in quail. Color variation in flycatchers. | − | Buggiotti (2007), Nadeau et al. (2007) |
Examples of involvement in wild bird species are also given. Chromosome assignation is based on the chicken (Gallus gallus) genome.