Fireproof or fiction: the science behind Daenerys Targaryen

Season six of Game of Thrones is just behind us, and our favourite Khaleesi featured heavily throughout the ten episodes. Daenerys is a gifted Targaryen who claims to have fire in her blood, and is thus able to tolerate scorching flames and other “hot stuff”. In one of the most iconic scenes from season one, Dany walks into a burning pyre and emerges unscathed and naked with newborn dragons on her shoulders.

Game of Thrones may be set in a magical realm with fictional creatures that have make-beileve powers, but the science behind the stories is sometimes not far from reality. For example, there are species on Earth that share a surprising number of similarities to the crazy critters from Game of Thrones.

Take the hyperthermophilic bacterium Pyrodictium, which grows in deep-sea vents and can withstand temperatures as high as 400 °C. The Targaryens, then, may just be another example of a hyperthermophile.

Daenerys is certainly not the first “dragon” Targaryen, which suggests that her heat tolerance was acquired from her predecessors. Given that many of the Targaryens died because of extreme heat, including Aerion Brightflame, Aegon the Unlikely, Duncan the Small, and even Dany’s own brother, Viserys, we can assume that the trait allowing Daenerys to withstand extreme heat is a recessive one.

So how have the Targaryens come to acquire this trait?

There are at least two possible answers to this question. When looking at Dany’s trait from a Darwinian perspective, we could argue that the Targaryens acquired heat-resistance through natural selection. Perhaps a random genetic mutation provided resistance to fire, which would certainly prove beneficial in the presence of dragons. Moreover, Daenerys only gained true respect and power from her peers once she proved that she was fireproof, adding even greater fitness to the trait. Indeed, possessing dragon-like abilities allowed the Targaryen family to rise in Westeros.

Alternatively, the hyperthermophilic qualities of the Targaryens could have been acquired directly from dragons. Instead of it being a genetic mutation that persisted through adaption, the heat-tolerance trait could have been obtained through lateral gene transfer, which is the movement of genes between different species. Lateral gene transfer is common within nature and one of the driving forces in evolution. In the Game of Thrones scenario, a gene bestowing fire resistance could have moved from the genome of a dragon to that of a Targaryen. If so, what would have driven this exchange? Whatever the cause, the Targaryens have clearly benefited.

Here’s hoping that I can get myself some good ol’ dragon genes.

This article was written by Nour Saleh, an undergraduate “Science Writer in Residence” from David Smith’s Lab at the University of Western Ontario.