Which Isnt Something Thats Happening - Tumblr Posts

Thoughts from an evolutionary biologist: Genetics is also like… slightly more complicated than that. The amount of DNA you share with a relative, aside from your parents, is variable. We can guarantee we share 50% (by direct descent) of our DNA with our parents, and we max out at 50% for any aunt or uncle (if I’m doing the math right, I’m not fully awake yet…although it’s extraordinarily unlikely that you’ll be that related to them, statistics-wise, average is gonna be 25%), and at 25% for each of our grandparents and cousins. It just depends on which copies of genes each person inherits. You’re likely more related to one of your grandparents than the others. You may share more DNA with your siblings than you do with either parent, or you might share less.

Of course, this is talking about similarity by direct descent. Your DNA might be even MORE similar to your relatives depending on the rate of homozygosity (for anyone who doesn’t do genetics: there are variations in the code at given locations in the genome. We each have two copies of each gene, with the exception of mitochondrial DNA, which comes only from our mothers, and sex chromosomes for men since they only have one X and one Y and the two chromosome carry different genes. There are typically two or more possibilities of variation in these specific locations. If you have two of the same, you are homozygous for that locus. If you have two different copies, you are heterozygous). Small populations that experience little migration (or simply populations that do not allow for interbreeding with other populations) will accrue higher rates of homozygosity over time and individuals will end up more related to each other based on identical sequences even if there isn’t any mating between direct relatives. So if your family consists of all people with blonde hair, blue eyes, attached earlobes, no dimples, no widows peak, no cleft chin, including the ones who married into the family (I used these examples because they guarantee homozygosity at their associated loci because they are recessive and require homozygosity to be expressed. You might be homozygous if you have brown eyes, but we can’t guarantee that because brown eyes are dominant and don’t require homozygosity for expression) your DNA will be more identical to all of your relatives because you all have the same copies of genes. This is how populations become “inbred.” To say a population is inbred doesn’t mean that the individuals are all reproducing with direct relatives. It just means that, due to a lack of migration, genetic variation has been lost and the rate of homozygosity has gone up. Valyrians in Westeros, because they try to only reproduce with Valyrians, are going to be a highly inbred group of people regardless of which Valyrian they reproduce with. It’s really here nor there for them genetics wise whether or not they reproduce with a sibling or a cousin or a Valyrian even less “related” (by direct descent) because so much of their DNA is already going to be identical either way.

But in modern times, this isn’t why incest is taboo. Our avoidance of incest *is* an evolutionary mechanism to avoid inbreeding. But we develop our rejection of relatives as mates based on lived experience. We can’t see each other’s DNA. Our brains don’t know who our relatives our. We infer this. When adults raise a child, their brain recognizes them as offspring whether or not there’s any relation. When you’re raised as siblings, your brain infers this relationship. That’s why it’s rather uncommon for very close childhood friends to develop romance later in life. When you spend so much time with someone as a child, you brain will assume you must be relatives. Because of the way our brains usually reject relatives as mates, most examples of incest involve abuse and coercion, especially since most involve age differences and the associated power dynamics, especially when there’s a whole generation separating the individuals. If it was really about avoiding inbreeding, we’d be having the same moral reaction to small isolated populations on islands and we’d judge people who’s partners look fairly similar to them (which happens often because we’re drawn to familiarity. For this reason, siblings separated at birth often feel attracted to eachother without knowing they’re siblings. Their features are familiar but they didn’t have the lived experience required for their brains to recognize eachother as relatives). But… we don’t. To give a personal example, this is why Jonrya isn’t my cup of tea (don’t hate it though, just personal preference, no judgement here) but I love Jonerys. The former would likely recognize each other as relatives due to their upbringing, but the latter never knew each other growing up. Would it be possible in real life after years of separation for people raised as siblings to fall in love? Probably. Is it possible in Westeros? Of course. Like I said, no judgement there.

Based on canon, we can assume that Valyrians have lost via evolution this mechanism that rejects their relatives as mates. There would be evolutionary incentive for this to happen. It isn’t impossible for selection to favor inbreeding and it’d be plausible for them. If we assume it’s true that a certain % Valyrian blood is required for dragon riding, they directly benefit from the effects of inbreeding. The fitness advantage conferred by bonding with a dragon outweighs any negative effects of the inbreeding, so individuals who are not repulsed by mating with relatives are going to be more “fit.” The smaller the reproducing population, the faster evolution occurs. This is all just my headcanon as an evolutionary biologist, but it would make perfect sense in-universe for the Valyrian lineage to have simply lost the instinct that makes them repulsed by incest.

But more importantly: it’s fiction. My headcanon aside, GRRM has not given us reason to think that Targaryen incest is abusive the way real life incest is. Some Targaryen marriages are miserable (i.e., Helaena and Aegon II) but not because they’re incestuous. Our morals may dictate what we personally like (Daemyra isn’t a ship I love, but I feel very neutral about it, no hate or judgement, and I do like to think that Daemon loved Rhaenyra to the end because I love Rhaenyra and want her to be happy) but we can’t use our morals to decide what’s moral in-universe. We have to look for evidence GRRM has given us and he has not given us evidence that the Targaryens are repulsed by incest and thus must be abused and coerced into these relationships.

Regular viewers: Daemon and Rhaenyra are uncle/niece. It is better than sibling marriage. Me, a medical student studying genetics... They are also cousins once removed by Aemma and twice C1R by Baelon/Alyssa (Viserys is sibling/cousin to Daemon), so it adds another roughly 18% of shared DNA between them to regular 25%.

And considering their parents and grandparents were hella inbred, they tranferred more genes to their children. Hm. From a purely genetical POV, Daemon and Rhaenyra are closer to reg. siblings. But shhh. Let's not tell this to all incestphobes in this fandom.

Ah nonnie is this about my Aegon-Helaena shippers call-out post? If it is, let me clarify that I have zero problems with fictional incest between siblings, I literally shipped the Borgia siblings who on top of that were real people 😇 I have a problem with Aegon and Helaena specifically because Helaena was a 13 yo child forced to marry a canon rapist who despised her (and everybody else) and their shippers are crackheads as a whole, as you saw in my post. And the reason I ship Daemyra is not because they are not that incestuous, I ship them because they are hot AF.

But thank you for your info.