The lavender phenotype in Japanese Quail is recessive and autosomal. It produces a dilution of both eumelanin (from black to blue or light grey) and phaeomelanin (from red/brown to buff or beige) in feathers. A similar phenotype is also known in several mammalian species (Mouse, Dog, Cat, Mink, Human) and in Chicken. All these phenotypes are caused by mutations in MLPH (Melanophilin) gene, which is involved in melanosomal transport in melanocytes. Homology between Japanese Quail and Chicken lavender loci has been demonstrated by hybridization between these animals (Minvielle et al., 2002). We have previously established that the mutation in chicken MLPH is a single-point mutation in exon 1, implying amino-acid change in protein (Vaez et al., 2008). By comparison of genomic organization in MLPH region between homozygous lavender and wild-type quails, we describe here that the mutation in Japanese Quail is surprisingly a large deletion encompassing the 3’end of MLPH gene (11exons out of 17 are deleted), the entire PRLH (Prolactin Releasing Hormone) gene and the 3’end of RAB17 (member of RAS oncogene family) gene (5 exons out of 6 are deleted).