ANIMALS
For the first time ever, scientists have created genetically modified snakes. The CRISPR-edited reptiles are providing new insight into how corn snakes (Pantherophis guttatus) develop their precisely patterned scales. Much like feathers on birds or hairs on mammals, snake scales are the result of placodes – small, thickened structures on the skin that develop at the embryonic level. But unlike most other species, including mice, where the placodes are random, a snake’s placodes develop in a highly organised fashion, laying out the positioning of every single scale. Rather, the spatial organisation of these placodes follows a pattern in nature first explained by mathematician Alan Turing.
Scientists from Geneva wanted to know exactly how and why these near-perfect hexagonal patterns developed on the dorsal scales located on the snakes’ backs and flanks, but not on the ventral scales that form as a single row on the animals’ underbellies.
The researchers found that an embryo’s ventral scales develop first and align with the position of somites, blocks of cells that determine the location of the vertebrae, ribs, muscles and dermis of the skin. Once the ventral scales are established, two separate ‘waves’ of placodes develop, travelling toward each other. The waves meet laterally, creating the tidy hexagonal patterns that are the hallmark of a snake’s skin.
“To confirm our work, we used computer simulations and received similar results,” said Athanasia Tzika, a postdoctoral fellow in the Department of Genetics and Evolution at the University of Geneva. “This is surprising because the pathway is ess
