The mutation leads to increased white body coloration and brightened yellow and orange areas. This morph arose as a spontaneous mutation in a female hatchling from a cross between two wildtype leopard geckos. Recently, histopathological findings of iridophoroma were reported in the Lemon Frost morph of leopard geckos. The genetic causes of iridophoroma in these species are unknown. White-colored iridophoroma is common in many reptile species, including green iguanas, captive snakes, bearded dragons and veiled chameleons. Uncontrolled proliferation of iridophores can lead to iridophoroma. These morphs either intensify a particular color ( S1A–S1I Fig) or rearrange coloration patterns ( S1J–S1L Fig).
The common leopard gecko, Eublepharis macularius, is an especially attractive model to study the molecular regulation of coloration because dozens of color and pattern morphs have been established over the past 30 years of selective breeding. The inheritance of different color morphs is usually carefully documented by breeders. g., geckos, chameleons, snakes) are bred in captivity as companion animals, and breeders have established morphs with unique colors and patterns.
In mammals, this pathway is required for melanocyte development, suggesting that signaling pathways conserved in evolution can be adapted to regulate different types of chromatophores. A recent study found that endothelin signaling regulates iridophore development and proliferation in zebrafish. In contrast with well-studied melanocytes, there have been few molecular genetic analyses involving iridophores. We know little of the molecular mechanisms of guanine crystal regulation. The form, number and distribution of the iridophores determine coloration and patterning of the organism. The size, morphology and organization of guanine crystals, which form reflective platelets within the iridophores, are considered the mechanisms of different colors. Different types of iridophores can lead to different colors, including blue, yellow, and white. Iridophores are not present in mammals, but are widespread in insects, fish, birds, amphibians and reptiles. Others, such as iridophores, produce colors structurally by making crystal platelets.
Some cells, such as melanocytes, produce pigments chemically. There are no patents, products in development or marketed products associated with this research to declare, and this does not alter our adherence to PLOS policies on sharing data.Ĭolor-producing cells contribute to animal coloration and patterns. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Ĭompeting interests: Steve Sykes is the owner of Geckos Etc. Herpetoculture provided support in the form of salary for SS. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.ĭata Availability: All sequencing data is available from the NCBI SRA database (accession number PRJNA730084).įunding: This work is supported by the Howard Hughes Medical Institute (to LK) and the Helen Hay Whitney Foundation (to LG). Received: FebruAccepted: Published: June 24, 2021Ĭopyright: © 2021 Guo et al. Hoekstra, Harvard University, UNITED STATES (2021) Genetics of white color and iridophoroma in “Lemon Frost” leopard geckos. Our work establishes the leopard gecko as a tractable genetic system and suggests that a tumor suppressor in melanocytes in humans can also suppress tumor development in iridophores in lizards.Ĭitation: Guo L, Bloom J, Sykes S, Huang E, Kashif Z, Pham E, et al.
We localized the mutation to a single locus which contains a strong candidate gene, SPINT1, a tumor suppressor implicated in human skin cutaneous melanoma (SKCM) and over-proliferation of epithelial cells in mice and zebrafish. We took advantage of a large breeding colony and used linkage analysis, synteny, and homozygosity mapping to investigate a spontaneous semi-dominant mutation, “Lemon Frost”, that produces white coloration and causes skin tumors (iridophoroma). The leopard gecko, Eublepharis macularius, is a popular companion animal, and displays a variety of coloration patterns. Due to a lack of genomic tools, few genetic studies in squamates have been carried out.
The squamates (lizards and snakes) are close relatives of birds and mammals, with more than 10,000 described species that display extensive variation in a number of important biological traits, including coloration, venom production, and regeneration.