Aragorn's Ancestry

Felarof

New Member
While catching up on Exploring LotR, I came across a part of ep 82 Where prof. Olsen says: "[quoting from Discord chat] If Strider took the Ancestry DNA test, what percentage of elf heritage would he see? [laughs] I'm not sure; you'd have to do the math; you could totally do the math on that. You know going back to Beren and Luthien, right and back through to Elros, figure out the genetic percentage of Elros Tar-Minyatur, and then do the math as it goes through generations. You can count the generations, as we're given the number of generations directly, so you could totally do the math. It would be small though. A quite small percentage. Trifle thinks it's sixty-four generations between Elros and Aragorn; that sounds about right; in the ballpark, anyhow." If you just want to know the percentage, the best estimate I came got to is 0.000000003638%. Here is the math behind that estimate. Elros Tar-Minyatur is 5/8 elvish (as Eärendil was half elvish and Elwing was 3/4 elvish) Elendil's line only breaks off until the 5th king of Numenor. So, as first I will do an estimation in which no spouses have elvish bood, before doing a more practical estimation, the denominator will rise from 8 (2^3) to 256 (2^8) at Valandil, son of Silmariën and 1st lord of Andúnië. This would then rise to 67,108,864 (2^26) for Elendil, 19th lord of Andunie (or rather the son of Amandil, 18th lord of Andunie). Now following Appendix A, one can count down to Earendur at 2^35, Arvedui at 2^50, and eventually come to Aragorn II (aka Strider) at 2^66. 2^66 is 73,786,976,294,838,206,464, so in this estimation Aragorn is 5/73,786,976,294,838,206,464 elvish. A better estimation would be include the elvish blood of the all of the wives (and Silmarien's husband Elatan). Here I estimated that Elatan and Silmarien were 5th cousins (or an equivalent situation) as marriages of closer relatives would likely have been illegal and it would have been improbable that inbreeding would have started much later in Numenor. One also has to guess the dates at which the Numenorean population in Middle-Earth would have grown small enough for the elvish blood to be mixed with more pure human blood. For the latter estimate I picked the fall of Arnor (so Beleg of Fornost would be the first to be born of an intermarriage with pure (or close to pure) humans. This would put Amlaith of Fornost at 5/256 (2^8); Arvedui at 2^21, and Aragorn at 2^37, which is 137,438,953,472. 5/137,438,953,472 calculates to 0.0000000000363797880709171295166015625 or 0.00000000363797880709171295166015625%, which can be rounded to 0.000000003638%. Finally the estimate of 64 generations between Elros and Aragorn is very accurate, as the actual measure is 63. Please comment if you find any miscalculations or you do not think my estimates for the amount of inbreeding are correct.
 
Please note that in this calculation the elvish and maia blood in Aragorn is all grouped into one. Also here is a much more in-depth (and most likely much more accurate) calculation: .

But remember that you can count the average amount only.

1. you assume then Aragorn's ancestors breed out to "pure" humans in each following generation. They do not - after a while they start marrying 2nd and 3th degree cousins. This preserves the amount of elvish ancestry in the offspring until it stabilizes just like we today have a stable amount of Neanderthal and Denisovan ancestry even if they have been no pure Neanderthals for about 40 000 years.

2. While you have always 50% from your parent the amount is average 25% from you grandparents. Otherways all siblings would be clones. Remember that a sibling only averages 50% genetical identity. The genetic similarity can be 0%-100% (identical twin) between siblings. In the 50% you get from your mother there could be 50% /50% from you maternal grandmother and grandfather, but it could as well be also e.g. 75% from your grandmother and only 25% from your grandfather. It will oscillate around 25% for each grandparent but never actually be it exactly. The amount of DNA from each grandparent in the respective cell given by the parent is random, averaging 50%, but seldom actually being exactly 50%. This is why sexual reproduction produces genetically diverse offspring, the recombination of grandparent's genes is each time different in each grandchild (identical twins excluded).

3. There are traits which are dominant like Luthien's shadowy dark hair, elvish gray eyes (the rarest eye colour among humans [real life] but estimated ca. 95% in elves) and elvish beardlessness, paleness of skin tone, that are inherited both by Aragorn and by Faramir and Boromir (those have some additional elvish blood from Mithrellas, even if this amount is not huge - but big enough for Legolas to spot it immediately in their uncle Imrahil). This means there are genetic markers which are so dominant that all offspring even down a hundred generations inherits those - just like there are Neanderthal genes that have almost completely replaced homo sapiens genes at specific places in most modern humans.
 
Only the first estimation (which came to 5/73,786,976,294,838,206,464) did not take inbreeding into account; the second estimation, which I view to be the better one, accounts for Aragorn's ancestors' marrying relatives of similar ancestry starting at Silmarien marrying Elatan whom I put down as her 5th cousin until the fall of Arnor. As for point 2, I believe my use of the word calculation as opposed to the more appropriate word estimation has led to this confusion; this is not and was never meant to be anything more accurate than an estimation. As for the third point, these traits seem to be independent of the genotype of the character, which would explain why the Faithful had more elvish characteristics than the rest of the Numenoreans by the time of the fall of Numenor. For example, maybe the allele for grey eyes is dominant in the faithful but not in others of similar genetics, or the gene for beardlessness is present in all men but only expressed in some, and when we learn that the Numenorean blood runs more true in Faramir than in Boromir, it could just mean that he expressed more Numenorean traits than Boromir.
 
the second estimation, which I view to be the better one, accounts for Aragorn's ancestors' marrying relatives of similar ancestry starting at Silmarien marrying Elatan whom I put down as her 5th cousin until the fall of Arnor.

Regarding the cousin issue - while elves have a problem in marrying 1st cousins, 1st cousins once removed and 2nd cousins seem fine
e.g. Nimloth was the daughter of Dior's 2nd cousin Galathil (2nd cousin once removed) while Celebrian was the first cousin of Nimloth so that Elrond ended up marring his own grandmother's 1st cousin (1st cousin twice removed) on her fathers side and - as Galadriel was a first cousin to Turgon her daughter was also Elrond's - 2nd cousin twice removed via her mother's side. No reason why the House of Elros should have been stricter here. Now add into the mix that Galadriel and Celeborn were 2nd cousins themselves and you have Elrond and Celebrian be related several times over.

Elwë mNelwë/Elmo mOlwë m
Luthien fGaladhon mEarwen fFinarfin mFingolfin m
Dior mGalathil mCeleborn mGaladriel fTurgon m
Elwing fNimloth f wife of DiorCelebrian f wife of ElrondIdril f
Elrond mEarendil m husband of Elwing
 
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