Biologists create beetle with functional extra eye
On "Game of Thrones," a three-eyed raven holds the secrets of the past, present and future in a vast fantasy kingdom. But for real-world biologists, a "three-eyed beetle" may offer a true glimpse into the future of studying evolutionary development.
Using a simple genetic tool, IU scientists have intentionally grown a fully functional extra eye in the center of the forehead of the common beetle. Unraveling the biological mechanisms behind this occurrence could help researchers understand how evolution draws upon pre-existing developmental and genetic "building blocks" to create novel complex traits, or "old" traits in novel places.
The study's results appear in the journal of the Proceedings of the National Academy of Sciences. The work also provides deeper insights into an earlier experiment that accidentally produced an extra eye as part of a study to understand how the insect head develops.
"Developmental biology is beautifully complex in part because there's no single gene for an eye, a brain, a butterfly's wing or a turtle's shell," said Armin P. Moczek, a professor in the IU Bloomington College of Arts and Sciences' Department of Biology. "Instead, thousands of individual genes and dozens of developmental processes come together to enable the formation of each of these traits.
Eduardo E. Zattara, Anna L. M. Macagno, Hannah A. Busey, Armin P. Moczek. Development of functional ectopic compound eyes in scarabaeid beetles by knockdown oforthodenticle. Proceedings of the National Academy of Sciences, 2017; 114 (45): 12021 DOI: 10.1073/pnas.1714895114
The creation of three-eyed beetles through a new technique developed at IU provides scientists a new way to investigate the genetic mechanisms responsible for the evolutionary emergence of new physical traits.Credit: Photo by Eduardo Zattara
