bethany81707 Posted March 19, 2017 Share Posted March 19, 2017 So I've been writing a story, and have managed to encounter a situation that seems somewhat curious. Basically, two characters are descendants of legendary figures who were siblings, and proceed to fall in love. When they realise their ancestors were siblings, they instinctively get concerned about being related. Naturally, falling somewhere between thirtieth and fortieth cousins can't really be considered 'related', but it does bring up an interesting question regardless: does a relationship where you can trace a common ancestor from hundreds of years ago seem squicky? Should it? Quote Link to comment Share on other sites More sharing options...
Flee Fleet! Posted March 19, 2017 Share Posted March 19, 2017 36 minutes ago, phineas81707 said: does a relationship where you can trace a common ancestor from hundreds of years ago seem squicky? Should it? Not really. Marriage between even first cousins is not too uncommon anyways, so... Quote Link to comment Share on other sites More sharing options...
Rezzy Posted March 19, 2017 Share Posted March 19, 2017 Once you get beyond first or second cousins, there's not really much more risk of passing down adverse recessive genes, at least, no more than the general population, unless there are generations of inbreeding, like the Habsburgs or something. We're all related, if you go back far enough, so unless they share a grandparent, it shouldn't really be much cause for squick. If they're thirteenth or fourteenth cousins, that would have to be centuries ago, and if you live in an even medium-sized city, there's a good chance your significant other shares that degree of relation to you. Quote Link to comment Share on other sites More sharing options...
Anacybele Posted March 19, 2017 Share Posted March 19, 2017 Yeah, what Rezzy said. I personally don't approve of first cousin relationships and closer, but anything farther than that is fine to me. Quote Link to comment Share on other sites More sharing options...
Dragoncat Posted March 19, 2017 Share Posted March 19, 2017 It would be kind of awkward, but yeah, there's no risk of genetic defects. And it was common in the middle ages for royal cousins to be married anyway...so I guess, are these characters royals or commoners? That might have some effect... Quote Link to comment Share on other sites More sharing options...
Res Posted March 19, 2017 Share Posted March 19, 2017 (edited) Not in the slightest. Sharing a common ancestor from hundreds of years ago gives you a really, really wide pool of people to choose from and it's likely that a lot of people are married to their distant cousins in this way. Third cousins only share 0.725% of their DNA on average and may not actually be related at all depending on what they inherited. 30th-40th cousins... you'd be related to entire countries if you go back that far. Going back 30 generations, or 1,000 years, and you have one billion ancestors. So basically if you have any shred of European blood in you, you're almost certainly related to everyone else who also has European blood. Edited March 19, 2017 by Res Quote Link to comment Share on other sites More sharing options...
Rezzy Posted March 19, 2017 Share Posted March 19, 2017 1 hour ago, Res said: Not in the slightest. Sharing a common ancestor from hundreds of years ago gives you a really, really wide pool of people to choose from and it's likely that a lot of people are married to their distant cousins in this way. Third cousins only share 0.725% of their DNA on average and may not actually be related at all depending on what they inherited. 30th-40th cousins... you'd be related to entire countries if you go back that far. Going back 30 generations, or 1,000 years, and you have one billion ancestors. So basically if you have any shred of European blood in you, you're related to everyone else who also has European blood. If last names are to be trusted as a sign of relation, I'm distantly related to one SF member, here. Quote Link to comment Share on other sites More sharing options...
bethany81707 Posted March 20, 2017 Author Share Posted March 20, 2017 9 hours ago, Dragoncat said: It would be kind of awkward, but yeah, there's no risk of genetic defects. And it was common in the middle ages for royal cousins to be married anyway...so I guess, are these characters royals or commoners? That might have some effect... Royals. A prince of one country and a princess of a different one. Quote Link to comment Share on other sites More sharing options...
eclipse Posted March 20, 2017 Share Posted March 20, 2017 If that were the case, then humanity wouldn't exist. At one point, the number of humans left on Earth was in the tens of thousands. Today, we're in the billions. First cousins MAY have issues if both siblings had some sort of genetic condition. However, if said siblings are the character's grandparents or later, it shouldn't be too much of a problem. Quote Link to comment Share on other sites More sharing options...
Dragoncat Posted March 20, 2017 Share Posted March 20, 2017 42 minutes ago, phineas81707 said: Royals. A prince of one country and a princess of a different one. It was also common for two countries to have their heirs married to strengthen the bond between the countries. So with that...and because they're not directly related as everyone's said, go for it. Quote Link to comment Share on other sites More sharing options...
___ Posted March 20, 2017 Share Posted March 20, 2017 Honestly, it doesn't seem to me that should even be an issue. Rather, it would seem like an interesting, if not a actually very cool, coincidence. Quote Link to comment Share on other sites More sharing options...
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