ESTABLISHING A SYSTEM TO UNCOVER THE ROLE OF THE NEURAL CREST IN THE DOMESTICATION OF THE FOX VULPES VULPES

Abstract

The mechanisms underlying the gain and loss of traits in natural selection remains a central question in biology. A valuable model to examine how selection acts to modify the body plan is domestication. As far back as 1868, Charles Darwin had noted in The Variation of Plants and Animals under Domestication that in diverse cases of domestication of mammals, a striking set of similar phenotypes emerge. These changes were not limited to behavior, but also included morphological changes in coat color, teeth size, craniofacial structures, and tail and ear development. In the 1950s, Dmitry K. Belyaev sought to explore domestication dynamics by breeding the silver fox (Vulpes vulpes) under stringent selection of a single trait, friendliness. Interestingly, the same domestication phenotypes re-appeared. Tame foxes showed higher instances of loss of pigmentation at the extremities of the body, a reduction in size of the snout and teeth, and a three- to five-fold reduction in adrenal cortisol. While domestication traits may appear unrelated, studies in developmental biology have revealed that many of these morphological features share a common embryonic origin. Much of the skull, the adrenal medulla, head and trunk pigment melanoblasts, and teeth precursors are derived from neural crest cells. The neural crest is an embryonic, multipotent stem cell population that originates from the dorsal section of the neural tube, migrates, and gives rise to dozens of cell-types in vertebrate embryos. While the neural crest has been speculated to be the link between the emergent traits of domestication syndrome, the molecular, cellular, and genomic changes underlying these phenotypes remain unresolved. To tackle this, I utilized cell reprogramming strategies to begin creating an in vitro model to molecularly and cellularly explore the role of the neural crest in domestication.