Jon Snow + Daenerys Targaryen far creepier genetically than you know

Screenshot 2016-06-14 22.09.51
Credit: poly-m (deviantART)

If you have been following Game of Thrones you have been noticing that there is a brewing romance between Jon Snow, King in the North, and Daenerys Targaryen, the aspiring claimant to her father’s Iron Throne.

Of course there is a twist to all of this: unbenknownst to either, Jon Snow’s biological father is Daenerys’ dead brother, Rhaegar. This means that Daenerys is Jon Snow’s aunt.

Long-time followers of the world of Game of Thrones are aware that incest between near relations is neither unknown nor shocking. But there is a non-trivial detail which it is important to note. Jon and Daenerys are far more closely related than typical aunts and nephews.

The reason is simple, Daenerys and her brother were the products of two generations of sibling incest. Incest results in inbreeding, and inbreeding as you know results in loss of genetic diversity. By Daenerys’ generation the coefficient of relationship between herself and her brothers was much higher than normal.

To be concrete, the coefficient of relationship of full-siblings is 0.50. That of half-siblings 0.25. Identical twins? Obviously 1.0. Another way to think about this is how much of the genome do any two pairs of individuals share in terms of long tracts of inheritance from recent ancestors. On the whole siblings share about half of their genomes in such a fashion. After two generations of inbreeding Daenerys and Rhaegar have a coefficient of relationship of 0.727 (using Wright’s method). They’re not identical twins, obviously, but their genetic relationship is far closer than full-siblings!

Don’t let the mother of dragons ride you Jon!

Dividing  this in half gives 0.36 as the coefficient of relationship between Jon and Daenerys, as opposed to 0.50 for full-siblings and 0.25 for a conventional aunt-nephew. Jon and Daenerys have almost the same genetic relationship as 3/4 siblings; two individuals who share a common parent, like half-siblings, but whose unshared parents are first order relatives (full-siblings or parent-child).

Not Jaime & Cersei creepy, but still creepy.

Addendum: Though Daenerys is quite inbred, Jon is not at all. One generation of outbreeding can eliminate all inbreeding.

16 thoughts on “Jon Snow + Daenerys Targaryen far creepier genetically than you know

  1. The monarchs of Europe were not quite that closely related, but almost. What difference did it make. WWI was a war between first order cousins.

  2. I think the books mention at one point that the brother-sister/close relations incest was a custom among the Valyrian elite. Maybe they’ve been doing it so long (and quietly euthanizing any offspring with issues that manifest before adulthood) that they’ve wiped out most of the negative recessive stuff.

    And of course as you said, Jon is not inbred because of his mother. The Starks don’t appear to ever have had any legitimate offspring with anyone from the Targaryen line, either.

  3. The monarchs of Europe were not quite that closely related, but almost. What difference did it make. WWI was a war between first order cousins.

    dance of the dragons?

    anyway, i calculated it (c related posts), D is more inbred than the last habsburg.

  4. You’re assuming, of course, that the show will hew towards the books in this regard (ancestry of Jon Snow). With the show making significant changes in other areas, what makes you think it won’t change this fact?

    Anyhow, I miss Ygritte. The only hot girl on the show. 😉

  5. what are you talking about? HBO confirmed his ancestry last year in a circular showing the pedigree. it’s the same as what ppl assumed from the books.

  6. “D is more inbred than the last habsburg”

    The heir apparent Ferdinand Zvonimir von Habsburg is not particularly inbred.

  7. “I miss Ygritte. The only hot girl on the show.”

    I miss her too but Ellaria Sand and Cersei Lannister are way hotter.

  8. What about the the Ptolemys of Egypt? There were quiet inbred and I think even worst than Targaryen.

  9. Ellaria Sand

    Hollywood seems to find Indira Varma (with her part-Indian/part-Swiss ancestry) versatile. She played a Roman wife in the HBO series “Rome” (which I found fantastic, mainly because of Kevin MacKidd’s acting – the best scowl on TV).

    Cersei Lannister

    Lena Headey was quite the firecracker back in the day. Check out her Scottish film “Aberdeen” from 2000. Since then she’s gone quite Hollywood, it seems. She looks worse as a blonde.

  10. As for this Dani + Jon thing, my wife’s take on it is, “It’s not icky, because the actress and the actor portraying them are not related and are attractive, young people. It WOULD be extremely icky in real life.”

  11. Lena Headey kicked butt in the movie 300 and the TV show The Sarah Connor Chronicles (inexplicably cancelled despite great ratings) which was better than some of the theatrical Terminator movies and due to the magic of time travel fit well within the canon. Her bad assed-ness is undoubtedly due to her father being a cop.

    Indira Varma seems miscast as a weepy and romantically sensitive detective sergeant in the TV series Pyramid.

    A D+J hookup would be the best cinematic incestuous relationship since Sam and Pilar in the John Sayles movie Lone Star.

  12. Right now in the show, the only person who knows John’s true identity is Bran. I expect he will spill the beans before J+D hook up.

  13. I expect he will spill the beans before J+D hook up.

    D might be even more into it. we’ll see if the valyrian or first men blood runs true in jon….

  14. “Check out her Scottish film “Aberdeen” from 2000.”

    On Prime with Charlotte Rampling and Stellan Skarsgard no less. I’ll watch it tonight!

  15. the best cinematic incestuous relationship since Sam and Pilar in the John Sayles movie Lone Star.

    She said she “was fixed, so it’s ok.”

  16. Let’s just hope that there isn’t big linkage between warging abilities and all the bad stuff. Cause clearly they’ve got some IBD there.

Comments are closed.