Is it possible to recreate dinosaurs from chicken DNA?

The dinosaur-bird connection hypothesis gained support in the 20th century as more fossilized remains were discovered, studied, and compared to modern birds.

We know that chickens are the closest living relatives of some of the most famous theropods, such as the Velociraptor and the Tyrannosaurus Rex. 

But does this mean that chickens could be the key to recreating these dinosaurs? Is it even true that scientists have managed to develop a “dino-chicken,” as some media have reported in the past?

Let’s find out.

From fiction to reality

In 1990, American author Michael Crichton published a science fiction novel called Jurassic Park, in which scientists find dinosaur DNA in the blood of ticks and mosquitoes preserved in amber and use it to bring dinosaurs back to life through cloning and recombinant technology. 

The story became popular thanks to its 1993 film adaptation, Steven Spielberg’s Jurassic Park, which initiated a whole franchise with, so far, seven films.

But how scientifically accurate is Jurassic Park’s plot? American paleontologist Jack Horner explained in a TED talk: “If you actually had a piece of amber and it had an insect in it, and you drilled into it and got something out of that insect, and cloned it over and over again, then you’d have a room full of mosquitoes.” 

What Jack Horner was trying to say is that dinosaur DNA can only be extracted from dinosaurs themselves. And while paleontologists have managed to retrieve lots of dinosaur materials — heme, soft tissues, protein fragments — over time, none of it contained intact, “usable” DNA.

The reason is that dinosaurs went extinct about 65 million years ago, and DNA is a fragile molecule that is not likely to survive that long, except in rare circumstances where conditions necessary for DNA preservation are met in nature. 

For example, we know that DNA is best preserved in cold and dry environments. That is why scientists artificially store DNA in ultra-low temperature freezers. In nature, DNA has been found well preserved in permafrost, which is the subsurface layer of soil found chiefly in polar regions that remains continually below 32°F (0ºC). 

In fact, in 2022, scientists from several countries retrieved traces of 2-million-year-old DNA from ancient animals and plants that once lived in Northern Greenland, revealing that the island wasn’t always the polar desert that it is today. 

Apparently, DNA is also well preserved in — surprise — amber. Amber is a type of fossilized tree resin formed from the sap of certain trees. When an insect or other small organisms get trapped in the sticky resin, it can become entombed within the resin as it hardens over time. This process can result in the preservation of the organism in near-perfect condition. Scientists have actually found 230-million-year-old mites preserved in amber, as well as other ancient animals. 

In some rare cases, amber can also preserve soft tissues and DNA. However, there is not enough evidence to claim that amber can help retrieve these materials from ancient organisms. In 2020, a team of researchers from the University of Bonn did, in fact, manage to extract DNA from amber-preserved insects —however, the insects had only been in the amber since 2014 - just seven years.

Recreated dinosaurs versus dino-chickens

So, if amber can’t preserve dinosaur DNA, then all we have is what can be found in the permafrost. The problem is that dinosaurs went extinct long before the formation of the oldest permafrost that we know of —one in Yukon, Canada, which is “just” 740,000 years old. Meaning, Jurassic Park — or the recreation of dinosaurs from their own DNA — is likely, not feasible in real life.

But what about recreating dinosaurs from chickens, their closest living relatives?

In 2006, researchers from the University of Wisconsin found a link between a specific chicken gene and tooth growth. 

Chicken embryos with a mutation on this gene developed sharp teeth, like those of an alligator —or a dinosaur. Although the mutated chicks didn’t make it to the hatching stage, the mutation itself showed that chickens retain the ability to grow teeth, and more specifically, dinosaur-like teeth. 

So what if we stimulated this growth using genetic engineering?

In 2015, a team of researchers from the University of Yale were investigating the developmental pathways that led to the evolution of the beaks of modern birds from the snouts of their dinosaur ancestors. 

In this context, they identified a set of genes known as "non-avian reptilian facial patterning genes,” which are believed to have played a key role in the development of the facial features of dinosaurs. 

By manipulating these genes in chicken embryos, the researchers were able to create embryos with snouts and palates that more closely resembled those of their dinosaur ancestors. 

They didn’t allow the genetically-modified chicken embryos to hatch, though.

Then, in 2016, a team of scientists from the University of Chile successfully created chicken embryos with “dinosaur legs.” 

Using a technique that involves manipulating the genetic pathways of developing embryos to recreate ancestral traits that have been lost over the course of evolution—, the team managed to inhibit the expression of the Indian Hedgehog (IHH) gene, which controls fibula development in chickens. This way, they managed to induce the growth of longer, more dinosaur-like fibulas in chicken embryos.

This reverses an evolutionary trait in a group of avian dinosaurs known as the Pygostylians, in which the fibula became shorter than the tibia and sharper and more splinter-like towards the end, and it no longer reached the ankle.

Similar studies have been conducted to identify genes that modify other traits. For example, it is known that chicken embryos have a relatively long tail that shortens as they develop into baby chicks. This is believed to happen after the activation of certain genes that instruct the body to reabsorb the tail. If these genes are identified and deactivated, we could have chickens with long, dinosaur-like tails in the future.

Ultimately, what this means is that there is no way to recreate actual dinosaurs, not even using chicken DNA. However, we could use genetic engineering techniques to stimulate atavisms (the reappearance of traits lost during the evolution of organisms) and or edit the genome of chickens to make them look more like dinosaurs — if the modified chicks survive the genetic editing without unintended consequences, and ethical concerns about animal welfare are addressed. Meanwhile, these experiments could help researchers to better understand the molecular mechanisms behind major evolutionary transitions.