Reverse Evolution? Bizarre Beak Experiment Hints at a 'Jurassic World' Future
Scientists have managed to successfully 'reverse evolve' the beaks of chicken embryos. The result very closely resembles the maws of long-gone dinosaurs, bolstering theories about the evolution of flight and - most stunningly - the potential to recreate prehistoric ancestors.
It's not exactly a rare thing to believe that birds evolved from dinosaurs. Heaps of compelling fossil and genomic evidence backing this idea are published every year (read a recap of 2014's greatest discoveries concerning the evolution of flight here) and paleontologists are finding that more and more members of the fossil record were at least feathered.
This has then led paleontologists and evolutionary theorists alike yearning to see that evolution for themselves. Just how did it happen? Is our current understanding of avian evolution spot-on or WAY-WAY off the mark?
That's where paleontologist Bhart-Anjan S. Bhullar and developmental biologist Arhat Abzhanov come in.
The researchers, from Yale and Harvard University respectively, spent the last eight years staring at chickens - their developing embryos in particular - in a bid to understand how modern beaks evolved from the ferocious dino maws that little kids fantasize about.
They think the beak is important, as it has constantly been used as a point of reference for determining where many long-extinct species should be placed on the tree of avian evolution. It doesn't have a beak but looks like a bird? It's probably a dinosaur! (Scroll to read on...)
It was also recently confirmed that chickens and turkeys are the closest modern relatives to the iconic "first bird," Archaeopteryx, and even earlier raptors, such as Hollywood's favorite, the Velociraptor.
Tweaking the Beak
Using the fossil record as a guide, the research pair set out to halt the molecular processes which likely changed the dino maw into the beaks we see today. However Bhullar is quick to add that he's not out to make a real-life Jurassic World.
"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," he said in a statement.
The researcher explained how the beak has long been thought to have been an unexpected consequence of a relatively simple mutation. In dinosaurs and even humans, there is a pair of small, separate bone plates sitting at the front of the upper jaw called premaxillae. They often help anchor front teeth, but during the early evolution of birds, experts suspect that these plates somehow stretched and fused.
"This is borne out by the fact that Hesperonis, which is a near relative of modern birds that still retains teeth and the most primitive stem avian with a modernized beak in the form of fused, elongate premaxillae, also possesses a modern bird palatine bone," Bhullar said, explaining that if birds and dinosaurs were unrelated, fossils like it likely wouldn't exist.
Closely analyzing their chicken embryos, Bhullar and Abzhanov quickly determined that the precursor to a beaked face is a large patch of cells pumping out the protein Fgf8. In the final stages of face formation, that patch will suddenly switch to making the protein Lef1 instead.
Other animals also use this two-protein process, but it is disbursed throughout many small patches of cells, rather than in one big cluster. The researchers guessed that if they were able to force chicken embryos to form a face in a more disbursed manner, they would find themselves with a dino-mawed chicken.
And sure enough, that's exactly what they saw. (Scroll to read on...)
The process and results are detailed in the journal Evolution.
"This was unexpected and demonstrates the way in which a single, simple developmental mechanism can have wide-ranging and unexpected effects," Bhullar said.
Just the Beginning
Still, don't expect a Jurassic World anytime soon. The researchers found that they are probably right about the protein changes, but they still don't know what exactly facilitates them in the first place. 'Reverse-evolving' a beak sill leaves us a very long way away from crafting whole dinosaurs out of chicken eggs.
Other researchers are trying their hand at bio-engineering other dino parts, too. For instance, Jack Horner, a paleontologist at Montana State University, hopes to take a genetic approach to imbuing chickens with dinosaur-like tails. What headway his team has made was published last year in the journal EvoDevo.
However, "we're having a little more trouble with the tail," he admitted to Nature magazine. "There are so many components."
Instead, the researcher suggested that this technology be applied to "making new kinds of animals," which scientists can then study and learn from - an approach that Bhullar applauds, but likely won't adapt. Wait... isn't that the same disaster scenario that Jurassic World is based around?!
Not to be a buzz-kill, but Hollywood loves to remind us that if science goes too far, we'll have an escaped, highly-intelligent, cannibalistic, man-eating mega-dinosaur on our hands. Let us... let's not have that.
Still, that's no reason to stop us from fantasizing about leading a raptor pack while riding a motorcycle through a jungle. Go get 'em Chris Pratt.
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