Scientists Establish Evolutionary Link Between Turtles And Birds

Missing link arguments, albeit weightless, are the most common statements used by creationists to oppose evolution, despite evidence providing non-linear links between different kinds of species. This week, a group of scientists from the California Academy of Sciences have added another to the pile, after successfully establishing an evolutionary link between turtles and their closest relatives: birds, crocodiles, and dinosaurs.

According to Science Daily, the scientists were able to establish a detailed “tree of life” for turtles, effectively providing more specific links between the reptiles and other animals in the class. Using state-of-the-art genome sequencing technique called Ultra Conserved Elements (UCE), the scientists were able to discover a massive amount of evolutionary and genetic information about turtles, providing a much deeper insight into their relations with other distant animal cousins.

The discovery allowed scientists to create a newly formed animal group called “Archelosauria,” classifying turtles, birds, and dinosaurs as close relatives. The creation of the group is a brand-new addition to the known tree of life of organisms.

Brian Simison, scientist and director of the Academy’s Center for Comparative Genomics (CCG) who analyzed the resulting data from the experiments, says “calling [the discover] is an exciting new era of sequencing technology is an understatement.”

“In the space of just five years, reasonably affordable studies using DNA sequencing have advanced from using only a handful of genetic markers to more than 2,000 — an unbelievable amount of DNA. New techniques like UCE dramatically improve our ability to help resolve decades-long evolutionary mysteries, giving us a clear picture of how animals like turtles evolved on our constantly-changing planet.”

James Parham, co-author of the study and a renowned turtle expert, says the technology involved in the study brings “a new level of clarity” in his research.

“I have been working on the evolutionary relationships of turtles for over 20 years using a variety of methods. Fossils are essential for showing us what extinct turtles looked like, but also in letting us know when and where they lived in the past. The turtle tree of life based on fossil turtle anatomy didn’t match up with the timing of their appearance in the fossil record, as well as their geography, but the tree of life generated at the Academy’s CCG is consistent with time and space patterns we’ve gathered from the fossil record. These new testing techniques help reconcile the information from DNA and fossils, making us confident that we’ve found the right tree.”

The study will be published on the latest issue of Molecular Phylogenetics and Evolution.

[Image from Laura Sharkey/Flickr]