In the classic movie “Jurassic Park,” scientists were able to use blood from fossilized mosquitoes to re-engineer dinosaur DNA, using frog DNA to splice any gaps. That’s more science fiction than fact, but researchers from Yale and Harvard University have been able to do something similarly amazing: Using chicken embryos and some genetic know-how, they’ve successfully induced ancestral molecular activity and caused the birds’ beaks to revert to their ancient developmental form. In other words, something approaching a modern day dinosaur.
The molecular development is what led to the snout formation in small dinosaurs like Velociraptor and Archaeopteryx, but don’t get your hopes up for a dino-themed amusement park just yet. The scientists say the exercise was for research purposes, not to create strange, Jurassic hybrids.
“Our goal here was to understand the molecular underpinnings of an important evolutionary transition, not to create a ‘dino-chicken’ simply for the sake of it,” Yale paleontologist and developmental biologist Bhart-Anjan S. Bhullar, lead author of the study.
Arriving at the mechanism was painstaking work. The researchers first developed a hypothesis via a detailed analysis of the anatomy of related fossils and extant animals. Specifically, they examined the embryos of emus, alligators, lizards, and turtles, and came to the conclusion that both the common neognath and the rarer paleognath bird lineages diverged significantly from both mammals and reptiles: All of the birds expressed a unique, median gene expression zone of two different facial development genes that had previously only been documented in chicken embryos.
From there, inducing dinosaur-like development was fairly simple. The researchers employed molecule inhibitors to block the proteins created by the bird-specific median signaling zone in the chicken embryos, and in doing so gave the embryo little choice but to continue developing along its ancestral path to a more dino-like snout. The beak structure indeed reverted, along with the palatine pone in the roof of the mouth, which surprised scientists.
Bhullar and his colleagues targeted the beak primarily because of its importance to birds’ everyday lives. Because they can be so specialized, it was clear to the researchers that some significant evolution had taken place.
“The beak is a crucial part of the avian feeding apparatus, and is the component of the avian skeleton that has perhaps diversified most extensively and most radically — consider flamingos, parrots, hawks, pelicans, and hummingbirds, among others,” Bhullar explained. “Yet little work has been done on what exactly a beak is, anatomically, and how it got that way either evolutionarily or developmentally.”
Finding proof that a single molecular mechanism was responsible for this one diversion opens the door to all kinds of possibilities, the researchers say. Based on this information, they believe there should be clear, identifiable linked transformations in the fossil records. They say that Hesperornis, for instance, a near-relative to modern birds, is indicative of this – it was the last bird-like animal to have teeth, but it also has a modern palatine bone.
In the mean time, the rest of us continue to hold out hope for a real-life Jurassic Park.