Cannibal Tadpole Sheds Light on Evolution and Development of Digestive Organs

Latest research from North Carolina State University suggests that a carnivorous, cannibalistic tadpole could provide clues in tracing the evolution and development of digestive organs, according to a news release.

The study, which appears in Evolution and Development, may also throw light on the universal rule of organ development that helps to better diagnose and prevent intestinal birth defects.

Conducted by Nanette Nascone-Yoder, an NC State developmental biologist along with Stephanie Bloom and postdoctoral candidate Cris Ledon-Rettig, the study focused on two different frog species. One is Xenopus Laevis (African clawed frog) and the other, Lepidobatrachus Laevis (Budgett's frog). The two frog species are different from each other in their diet and interestingly, they seem to have shared a common ancestor in the past 110 million years.

Common to most tadpoles, the diet of the Xenopus consists of algae and until they transform into adult frogs, their long and simple digestive tracts fail to process insects or proteins. On the other hand, the aggressive Budgett's frog is carnivorous and cannibalistic in its tadpole stage.

The researchers were familiar with the fact that Budgett's tadpole had a shorter and more complex gut that could help them digest protein early in their development. In this study, the team exposed Xenopus embryos to certain molecules that calmed down an array of genes to check if they might entice them to grow a carnivore-like digestive tract.

On doing so, they noticed that five molecules triggered the Xenopus to develop guts that were remarkably similar to that of the Budgett's. Later, they exposed the embryos of Budgett's frog to molecules that had an opposite effect, and got tadpole guts that were closer to those of the Xenopus.

"Essentially, these molecules are allowing us to tease apart the processes that play a key role in gut development," Nascone-Yoder said in a press statement. "Understanding how and why the gut develops different shapes and lengths to adapt to different diets and environments during evolution gives us insight into what types of processes can be altered in the context of human birth defects, another scenario in which the gut also changes its shape and function."