In Greek mythology, cyclopes existed as cave-dwelling, one-eyed giants. The myth of the cyclops had its origins in the Greek’s discovery of giant skulls with single holes in the center, presumed to be single eye-sockets. Today, scientists speculate that those skulls belonged to elephants, sadly negating the giant cyclopes myth (History, 2015). Thankfully, a visit with my NBB class in Paris returned my hope. This week at the Musée Fragonard of the École nationale vétérinaire d’Alfort, I learned that cyclopes did exist, although perhaps in not such an exciting mythical form. The museum, which is dedicated to preserving art pieces and specimens of “monster” animals and animal body parts, had a cyclops skull, as well as models of cyclopes farm animals that once existed in Europe. According to our veterinary student tour guide, there was a time in Europe when a plant mutation cause cyclopia to be prevalent in farm animals. Hello one-eyed chicken! Today, about 1 in 100,000 human babies are identified as having cyclopia, none of whom are able to survive with the mutation (Salama et. al., 2015). I decided to look into the neuro-origins of cyclopia, to see how this mythical phenotype develops in the early nervous system.
According to a study conducted in zebrafish, cyclopia is accompanied by several other neural deficiencies (Strähle et al., 1993). The biggest commonality in cyclopia victims is the lack of a neural floor plate. The floor plate is developed in early embryos by signaling cascades and becomes responsible for the formation of glial cells, which are essential to helping neurons function, cell proliferation, as well as many other functions. The cyclopia mutation most likely inhibits the genes that encode for the signaling that would normally develop the neural tube (including the floor plate), neural crest cells and epidermis cells during embryogenesis. These cells specialize to form our entire nervous system, facial cartilage and eyes. Without this essential signaling, a cyclops is unableto develop a normal nervous system or the facial cartilage that is needed to separates their eyes.
Even though I spent the last year conducting research on nervous system embryogenesis, I feel like I am always learning more. There are so many important biological processes that contribute to the development of our brain, many of which we are still trying to understand.
Knowing the science behind cyclopia doesn’t make the cyclopes any less mythical. In France, many have come to appreciate the unconventional beauty of the creature. In 1969, French artist Jean Tinguely created a 22 meter-high sculpture called Le Cyclop. The site of the piece now hosts interactive activities for visitors to explore the history of contemporary art.
References:
History. (2015). True Monsters: The Skull of a Cyclops [Video file]. Retrieved from https://www.youtube.com/watch?v=lLgYrbDfMPs
Salama, G. S., Kaabneh, M. A., Al-Raqad, M. K., Al-Abdallah, I. M., Shakkoury, A. G., & Halaseh, R. A. (2015). Cyclopia: a rare condition with unusual presentation-a case report. Clinical Medicine Insights: Pediatrics, 9, CMPed-S21107.
Strähle, U., Blader, P., Henrique, D., & Ingham, P. W. (1993). Axial, a zebrafish gene expressed along the developing body axis, shows altered expression in cyclops mutant embryos. Genes & Development, 7(7b), 1436-1446.
Find info about Le Cylop sculpture here: http://www.lecyclop.com/Artistes-Artists