(Author: Eric Malikyte)

It’s a scientific study that I’ve mentioned multiple times and a story that set the internet ablaze with rampant speculation and in some cases outright misinformation.

Yes, you requested it, and we’re going to be talking about that little genetic experiment involving chicken embryos and dinosaur-like snouts.

In-situ hybridisation on chicken embryo.jpg by Simone Castellana – Own work, CC BY-SA 4.0

The KT Extinction

As many of you know, the KT extinction event was the beginning of the end for the dinosaurs on this planet. An asteroid that’s estimated to have been around 15 kilometers wide slammed into the Earth, wiping out 70% of all plants and animals on the surface, and leaving a crater (or a scar, if you want to wax poetic) that is 150 kilometers wide and can still be seen today.

The extinction of the dinosaurs was not immediate, however. For weeks after the impact, the sun was blocked out by huge clouds of dust that caused temperatures to plummet to deadly levels.

You can visit the Chicxulube crater today in the Yucatan peninsula, and as you can see here from this footage I took from Google Earth, the boundary of the crater (though eroded) can still be clearly seen. And if you’re wondering how we know this impact crater is the most likely candidate for the KT extinction crater, the rare metal, iridium is 30 times higher in the Earth’s crust that dates back to the time of the KT extinction. Iridium is super common in asteroids, and it just so happens that the crater itself holds quite a bit of iridium as well. Dating the crater, it fits quite nicely with the timing of the KT extinction event.

There’s more to it too, but we’ve got a lot to cover, so let’s get a move on.

Despite the fact that the largest dinosaurs were wiped out both during the impact and the climatic aftermath that followed, there are still dinosaurs on Earth. Today, the closest living relatives of the dinosaurs are birds.

But one question that has puzzled scientists since the discovery of Archaeopteryx is how they went from having dinosaur-like snouts to having beaks?

That’s exactly what a team of scientists set out to figure out!

Chicken Dinos?

First, I’ve got to mention the false claims that scientists had successfully harvested an embryo from a fossilized pregnant T-Rex. This is definitely not the case, and the site that reported on this (World News Daily Report) is a notorious fake news site. Not only is it highly unlikely that a fossilized pregnant T-Rex could have its embryos harvested (because, you know, they’re freaking fossilized!) but it’s equally impossible to somehow infuse those embryos into a chicken’s skin and suddenly get a T-Rex. (I mean, did they do any research before diving into this piece? Do they even know how DNA works?)

A normal chicken embryo

While it would undoubtedly be cool if T-Rex’s were to be resurrected through science (before they started eating people and fighting raptors that is), the study we’re about to talk about is so much more interesting, because the implications of the experiment could help us answer some pretty important questions about why beaks evolved in the first place.

As mentioned before, Archaeopteryx was very similar to modern-day birds in many respects but featured a dinosaur snout rather than a beak. Scientists have long wanted to understand why it is that the surviving dinosaur species evolved into birds, and why they developed beaks in the process.

Back in 2015, it was reported that a team of scientists at the University of Chicago in Illinois set out to answer the question by messing with the molecules in the DNA of a bunch of chicken embryos.

And as the result of those tweaks in the DNA, those chicken embryos lost their trademark beaks and formed snouts that are very much like a dinosaur’s.

But if you’re crying out to stop these scientists from unleashing their hoard of chicken dinos upon the Earth, you don’t have to worry, because the embryos have not been allowed to hatch (so calm down Ian Malcolm, everything’s fine!).

Okay, so how did they do it?

Well, the team looked at the developing beaks in embryos of chickens and emus, as well as the development of snouts in alligators, turtles, and lizards, and what they found was that two proteins in DNA seemed to control the development of beaks.

As dinosaurs evolved into birds evolved their snouts slowly transformed into modern-day beaks, losing the teeth they once had. Credit: Luis Pérez López CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0)

It seems that in reptiles, these two proteins (called FGF and Wnt) act upon two small parts of the embryonic face, and when you look at birds, the same proteins were active in a large band of tissue in the same area.

So, all they really needed to do was test to see if the difference of protein activity is the true cause for beak development in birds. They accomplished this by blocking the wide band where FGF and Wnt were active in their developing chicken embryos and restrict them to the same areas where they were activated in reptiles. They accomplished this by using small molecule inhibitors.

The results were absolutely striking. A flap of skin covered the area of the snout where the beak would have been, and underneath, they had shorter, more rounded bones than the longer, fused beaks found in birds.

So, okay, that’s cool, but what does this really mean?

Implications

The researchers who conducted this experiment believe that their results prove that the evolution of the beak was a wholly new adaptation in early evolving birds, rather than just another variation on the shape of a nose.

Before this, there hadn’t really been too much research on figuring out what exactly a beak is anatomically, but we knew that it’s a crucial part of a bird’s feeding apparatus.

Bhullar et al, Evolution 2015

And though the embryos were never allowed to hatch, Bhart-Anjan S. Bhullar (lead author behind the study published in Evolution) believes that the chicken-dinos (that’s what I’m calling them) would have lived a healthy life, as the change wasn’t a major one.

But just like with the experiment we talked about with the Marmoset fetus and its enlarged brain, we have a similar situation. There are simply too many ethical questions when thinking about allowing these critters to develop. While it’s not nearly as drastic as causing an enlargement of the brain itself (as in the Marmoset case) it’s still enough of an unknown that researchers would rather stay on the safe side.

There are still many questions regarding how the first beaks developed, though. We’re still a long way from answering or understanding the molecular changes which led to their evolution, but at the same time, Bhullar believes that identifying what proteins are responsible now is a great start to answering that question.

So, no, Jurassic Park is not happening anytime soon (or probably ever, considering it’s a terrible idea in the first place), but something far more interesting may happen in future experiments, as we continue to understand how and why dinosaurs evolved into birds. And you can bet we’ll be here to talk about it when that happens!

http://www.bbc.com/earth/story/20150512-bird-grows-face-of-dinosaur

https://www.smithsonianmag.com/smart-news/chicken-embryos-get-dino-snouts-thanks-biological-tinkering-180955250/

https://www.nhm.ac.uk/discover/how-an-asteroid-caused-extinction-of-dinosaurs.html#:~:text=The%20asteroid%20is%20thought%20to,largest%20crater%20on%20the%20planet.

https://www.pbs.org/wgbh/evolution/extinction/dinosaurs/asteroid.html