Mutation of a gene in the corn snake has allowed a group of scientists from the University of Geneva (UNIGE) to understand the origin of the different colors and patterns present on the skin of all vertebrate species, according to A study published this Monday in the scientific journal PNAS.

Scientists have discovered that the mutation in the corn snake of a gene involved in formation of lysosomes, Organelles located in cells and which are responsible for the digestion of non-functional molecules, is responsible for all the different skin colors.

The detection of this mutation has allowed the team of specialists in genetic determinism and color evolution in reptiles to demonstrate that both the reflective crystals and the pigments that give color to the skin are stored in vesicles related to lysosomes.

The color of the skin in vertebrates depends on chromatophores, cells located in the deeper layers of the skin with pigments and crystals that reflect light.

There are three types of chromatophores. Melanforos are responsible for colors black and brown, xanthophores, which produce Red and yellow, and the iridophores, crystals that reflect multiple colors.

Mammals only have melanphores while reptiles and fish have all three types of chromatophores so they are capable of displaying a wide variety of colors and patterns.

Vesicles between cells

Melanphor pigments are stored in organelles known as ORL, vesicles located between cells. But scientists they still haven’t figured out where the red and yellow pigments are stored, as well as the crystals, of the other types of chromatophores.

Experiments carried out by Athanasia Tzika, one of the UNIGE researchers with corn snakes, have identified a mutation in the LYST gene, that regulates lysosomes, as responsible for the different colors of the reptile.

Corn snakes have an orange base, decorated with black polka dots. But the mutation causes that there are snakes with the skin of pink color and gray polka dots.


Precisely, the LYST gene mutation in humans is responsible for the síndrome Chediak-Higashi characterized by albinism, a damaged immune system, and large lysosomes.

Professor Michel Milinkovitch, from UNIGE’s Department of Genetics and Evolution, stated that “by characterizing the mutant gene, the study has shown for the first time that the different chromatophores they weren’t created out of thin air during evolution rather they all involve a basic mechanism that wraps ORLs “.

The UNIGE team added that “more studies will be needed to understand the mechanisms responsible for the variety of skin colors and patterns in vertebrates “.