You can read more about how birds are totally dinosaurs in our previous post on the subject. But it's pretty simple. Birds are dinosaurs. Say it with me now: Birds. Are. Dinosaurs. It's true that all of the species that we consider dinosaurs are long extinct, and plenty of lineages went extinct, too. But one branch of the dinosaur family — the one that managed to shrink the fastest — produced the oldest common ancestor of all living birds.
Which is pretty obvious when you look at them:
In fact, one recent study actually used chickens to better understand how earlier dinosaurs may have strutted around back in the day. The main difference is that dinosaurs had tails, so scientists naturally decided to stick little plungers on some chicken butts and see how they'd manage.
But that doesn't mean that a chicken with, you know, non-chicken-dinosaur legs isn't impressive. This is a brilliant feat of genetic engineering. The chickens-with-legs-from-dinosaurs-that-were-not-chickens were developed by scientists at the University of Chile, and are described in a paper published earlier this month in the journal Evolution.
Modern birds have leg bones that are a tad different from those we see in their ancient ancestors. In older dinosaurs, the fibula was long and tube-shaped, reaching all the way down to the ankle. In modern birds, this bone thins out and shortens relative to the other bones in the leg.
But during embryonic development, there's a period when the fibula seems poised to grow dino-like — so the researchers, led by Joâo Botelho, inhibited a gene called Indian Hedgehog to keep the leg from maturing in typical chicken-like fashion.
"The experiments are focused on single traits to test specific hypotheses," study author Alexander Vargas said in a statement. "Not only do we know a great deal about bird development, but also about the dinosaur-bird transition, which is well-documented by the fossil record. This leads naturally to hypotheses on the evolution of development, which can be explored in the lab."
The same team had previously manipulated chicken genes to create embryos without the perching toe modern birds have developed, and another group at Yale had modified beak-related genes to produce the kind of reptilian snout we associate with "true" dinosaurs.
All of this is possible because of the underlying genetic similarities between birds and their dino ancestors. As scientists get better and better at using the gene editing tool CRISPR, making changes like these — silencing or activating a few genes to bring an animal closer to its ancestors — may become routine.
But let's not count our dino-chickens before they've hatched: For now, none of the experiments have attempted to produce living animals from the tweaked embryos.