Tags

Type your tag names separated by a space and hit enter

Evolutionary origin and development of snake fangs.
Nature 2008; 454(7204):630-3Nat

Abstract

Many advanced snakes use fangs-specialized teeth associated with a venom gland-to introduce venom into prey or attacker. Various front- and rear-fanged groups are recognized, according to whether their fangs are positioned anterior (for example cobras and vipers) or posterior (for example grass snakes) in the upper jaw. A fundamental controversy in snake evolution is whether or not front and rear fangs share the same evolutionary and developmental origin. Resolving this controversy could identify a major evolutionary transition underlying the massive radiation of advanced snakes, and the associated developmental events. Here we examine this issue by visualizing the tooth-forming epithelium in the upper jaw of 96 snake embryos, covering eight species. We use the sonic hedgehog gene as a marker, and three-dimensionally reconstruct the development in 41 of the embryos. We show that front fangs develop from the posterior end of the upper jaw, and are strikingly similar in morphogenesis to rear fangs. This is consistent with their being homologous. In front-fanged snakes, the anterior part of the upper jaw lacks sonic hedgehog expression, and ontogenetic allometry displaces the fang from its posterior developmental origin to its adult front position-consistent with an ancestral posterior position of the front fang. In rear-fanged snakes, the fangs develop from an independent posterior dental lamina and retain their posterior position. In light of our findings, we put forward a new model for the evolution of snake fangs: a posterior subregion of the tooth-forming epithelium became developmentally uncoupled from the remaining dentition, which allowed the posterior teeth to evolve independently and in close association with the venom gland, becoming highly modified in different lineages. This developmental event could have facilitated the massive radiation of advanced snakes in the Cenozoic era, resulting in the spectacular diversity of snakes seen today.

Authors+Show Affiliations

Institute of Biology, Leiden University, Kaiserstraat 63, PO Box 9516, 2300 RA, Leiden, The Netherlands.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

18668106

Citation

Vonk, Freek J., et al. "Evolutionary Origin and Development of Snake Fangs." Nature, vol. 454, no. 7204, 2008, pp. 630-3.
Vonk FJ, Admiraal JF, Jackson K, et al. Evolutionary origin and development of snake fangs. Nature. 2008;454(7204):630-3.
Vonk, F. J., Admiraal, J. F., Jackson, K., Reshef, R., de Bakker, M. A., Vanderschoot, K., ... Richardson, M. K. (2008). Evolutionary origin and development of snake fangs. Nature, 454(7204), pp. 630-3. doi:10.1038/nature07178.
Vonk FJ, et al. Evolutionary Origin and Development of Snake Fangs. Nature. 2008 Jul 31;454(7204):630-3. PubMed PMID: 18668106.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Evolutionary origin and development of snake fangs. AU - Vonk,Freek J, AU - Admiraal,Jeroen F, AU - Jackson,Kate, AU - Reshef,Ram, AU - de Bakker,Merijn A G, AU - Vanderschoot,Kim, AU - van den Berge,Iris, AU - van Atten,Marit, AU - Burgerhout,Erik, AU - Beck,Andrew, AU - Mirtschin,Peter J, AU - Kochva,Elazar, AU - Witte,Frans, AU - Fry,Bryan G, AU - Woods,Anthony E, AU - Richardson,Michael K, PY - 2007/11/02/received PY - 2008/06/19/accepted PY - 2008/8/1/pubmed PY - 2008/8/12/medline PY - 2008/8/1/entrez SP - 630 EP - 3 JF - Nature JO - Nature VL - 454 IS - 7204 N2 - Many advanced snakes use fangs-specialized teeth associated with a venom gland-to introduce venom into prey or attacker. Various front- and rear-fanged groups are recognized, according to whether their fangs are positioned anterior (for example cobras and vipers) or posterior (for example grass snakes) in the upper jaw. A fundamental controversy in snake evolution is whether or not front and rear fangs share the same evolutionary and developmental origin. Resolving this controversy could identify a major evolutionary transition underlying the massive radiation of advanced snakes, and the associated developmental events. Here we examine this issue by visualizing the tooth-forming epithelium in the upper jaw of 96 snake embryos, covering eight species. We use the sonic hedgehog gene as a marker, and three-dimensionally reconstruct the development in 41 of the embryos. We show that front fangs develop from the posterior end of the upper jaw, and are strikingly similar in morphogenesis to rear fangs. This is consistent with their being homologous. In front-fanged snakes, the anterior part of the upper jaw lacks sonic hedgehog expression, and ontogenetic allometry displaces the fang from its posterior developmental origin to its adult front position-consistent with an ancestral posterior position of the front fang. In rear-fanged snakes, the fangs develop from an independent posterior dental lamina and retain their posterior position. In light of our findings, we put forward a new model for the evolution of snake fangs: a posterior subregion of the tooth-forming epithelium became developmentally uncoupled from the remaining dentition, which allowed the posterior teeth to evolve independently and in close association with the venom gland, becoming highly modified in different lineages. This developmental event could have facilitated the massive radiation of advanced snakes in the Cenozoic era, resulting in the spectacular diversity of snakes seen today. SN - 1476-4687 UR - https://www.unboundmedicine.com/medline/citation/18668106/Evolutionary_origin_and_development_of_snake_fangs_ L2 - https://doi.org/10.1038/nature07178 DB - PRIME DP - Unbound Medicine ER -