What are the chances two rich, white Americans are related?
July 25, 2005 9:32 AM Subscribe
During the 2004 election, I'm sure we all heard that George W. Bush and John Kerry were related. But given any two people of similar backgrounds, what are the chances that they are related?
If you're running for POTUS, you're likely rich and white. Often you'd come from a long line of quasi-prominent politcal/business/other leaders, though not necessarily. So, what's the likelihood that the 2008 Republic and Democratic candidates will be somehow related, given the blueblooded characteristics of the rich?
What's the likelihood that if you picked two people racially and economically similar people off the street that they'd be related? Seems like the whole guess-who's-realted-to-whom industry is vibrant, but I'm wondering if finding two people who are ironically distant relatives is really all that ironic.
If you're running for POTUS, you're likely rich and white. Often you'd come from a long line of quasi-prominent politcal/business/other leaders, though not necessarily. So, what's the likelihood that the 2008 Republic and Democratic candidates will be somehow related, given the blueblooded characteristics of the rich?
What's the likelihood that if you picked two people racially and economically similar people off the street that they'd be related? Seems like the whole guess-who's-realted-to-whom industry is vibrant, but I'm wondering if finding two people who are ironically distant relatives is really all that ironic.
Response by poster: I'm sure it's easy to make the argument that if you go back far enough, everyone's related to everyone. For the sake of argument, though, let's stay within the realm of reasonable genealogical record (?)
posted by clearlynuts at 9:48 AM on July 25, 2005
posted by clearlynuts at 9:48 AM on July 25, 2005
Bill Bryson puts it nicely:
If your two parents hadn't bonded just when they did - possibly to the nanosecond - you wouldn't be here. And if their parents hadn't bonded in a precisely timely manner, you wouldn't be here either. And if their parents hadn't done likewise, and their parents before them, and so on, obviously and indefinitely, you wouldn't be here.
Push backwards through time and these ancestral debts begin to add up. Go back just eight generations ... and already there are over 250 people on whose timely couplings your existence depends. Continue further, to the time of Shakespeare ... and you have no fewer than 16,384 ancestors ...
At twenty generations ago, the number of people procreating on your behalf has risen to 1,048,576. Five generations before that, and there are no fewer than 33,554,432 men and women on whose devoted couplings our existence depends. By thirty generations ago, your total number of forebears - remember, these aren't cousins and aunts and other incidental relatives, but only parents and parents of parents in a line leading ineluctably to you - is over one billion (1,073,741,824, to be precise). If you go back sixty-four generations, to the time of the Romans, the number of people on whose cooperative efforts your eventual existence depends has risen to approximately 1,000,000,000,000,000,000, which is several thousand times the total number of people who have ever lived.
Clearly something has gone wrong with our math here. The answer, it may interest you to learn, is that your line is not pure. You couldn't be here without a little incest - actually quite a lot of incest - albeit at a genetically discreet remove. With so many millions of ancestors in your background, there will have been many occasions when a relative from your mother's side of the family has procreated with some distant cousin from your father's ... In fact, if you are in a partnership now with someone from your own race and country, the chances are excellent that you are at some level related. Indeed, if you look around you on a bus or in a park or café or any crowded place, most of the people you see are very probably relatives. When someone boasts to you that he is descended from William the Conqueror or the Mayflower Pilgrims, you should answer at once: "Me, too!" In the most literal and fundamental sense we are all family.
posted by Robot Johnny at 9:53 AM on July 25, 2005
If your two parents hadn't bonded just when they did - possibly to the nanosecond - you wouldn't be here. And if their parents hadn't bonded in a precisely timely manner, you wouldn't be here either. And if their parents hadn't done likewise, and their parents before them, and so on, obviously and indefinitely, you wouldn't be here.
Push backwards through time and these ancestral debts begin to add up. Go back just eight generations ... and already there are over 250 people on whose timely couplings your existence depends. Continue further, to the time of Shakespeare ... and you have no fewer than 16,384 ancestors ...
At twenty generations ago, the number of people procreating on your behalf has risen to 1,048,576. Five generations before that, and there are no fewer than 33,554,432 men and women on whose devoted couplings our existence depends. By thirty generations ago, your total number of forebears - remember, these aren't cousins and aunts and other incidental relatives, but only parents and parents of parents in a line leading ineluctably to you - is over one billion (1,073,741,824, to be precise). If you go back sixty-four generations, to the time of the Romans, the number of people on whose cooperative efforts your eventual existence depends has risen to approximately 1,000,000,000,000,000,000, which is several thousand times the total number of people who have ever lived.
Clearly something has gone wrong with our math here. The answer, it may interest you to learn, is that your line is not pure. You couldn't be here without a little incest - actually quite a lot of incest - albeit at a genetically discreet remove. With so many millions of ancestors in your background, there will have been many occasions when a relative from your mother's side of the family has procreated with some distant cousin from your father's ... In fact, if you are in a partnership now with someone from your own race and country, the chances are excellent that you are at some level related. Indeed, if you look around you on a bus or in a park or café or any crowded place, most of the people you see are very probably relatives. When someone boasts to you that he is descended from William the Conqueror or the Mayflower Pilgrims, you should answer at once: "Me, too!" In the most literal and fundamental sense we are all family.
posted by Robot Johnny at 9:53 AM on July 25, 2005
There's been a lot of work on modeling this.
I'll leave you with this link to how common ancestors can be calculated and to this link from another mefite explaining random descent networks.
The classic mistake (as Gyan made above) is to deal with single-parent networks. But of course we all have 2 parents, 4 grandparents, 8 great-grandparents etc., an exploding number of ancestors and yet a small historical population.
Anyways, it has been controversially derived that we are all so inter-related that an ancestor that we ALL have in common may have existed within the past 2,000 years.
posted by vacapinta at 10:01 AM on July 25, 2005
I'll leave you with this link to how common ancestors can be calculated and to this link from another mefite explaining random descent networks.
The classic mistake (as Gyan made above) is to deal with single-parent networks. But of course we all have 2 parents, 4 grandparents, 8 great-grandparents etc., an exploding number of ancestors and yet a small historical population.
Anyways, it has been controversially derived that we are all so inter-related that an ancestor that we ALL have in common may have existed within the past 2,000 years.
posted by vacapinta at 10:01 AM on July 25, 2005
I wasn't claiming that Eve is the nearest point of convergence. Just pointing out that without specifying closeness, the post is useless, hence the question.
posted by Gyan at 10:07 AM on July 25, 2005
posted by Gyan at 10:07 AM on July 25, 2005
I'm sure it's easy to make the argument that if you go back far enough, everyone's related to everyone.
Once upon a time (probably here at Metafilter) I ran across a study that used mathematics and probability to calculate that point; it was surprisingly recent. Around the reign of Charlemagne, if I remember correctly. I'd love to have that link again (hint hint.)
posted by junkbox at 1:14 PM on July 25, 2005
Once upon a time (probably here at Metafilter) I ran across a study that used mathematics and probability to calculate that point; it was surprisingly recent. Around the reign of Charlemagne, if I remember correctly. I'd love to have that link again (hint hint.)
posted by junkbox at 1:14 PM on July 25, 2005
Aha - all praise the search feature. Too bad most of the links are dead now.
posted by junkbox at 1:17 PM on July 25, 2005
posted by junkbox at 1:17 PM on July 25, 2005
Yes, mefite myl is the author of that second link I posted.
posted by vacapinta at 2:04 PM on July 25, 2005
posted by vacapinta at 2:04 PM on July 25, 2005
This is pretty easy to BOTE.
If you go back 10 generations, you have 2^10 N-grandparents, or 1024. If you merely assume they each spawned two children, on average (not likely for the earlier generations, but then again I don't know what the actual average is including terminal lines), you have 1024 * 1024, or 1,048,576. In the broadest sense, using this model, there's a 0.3% chance of being related within 10 generations to a random American you meet on the street. If the model assumes an average of 3 children, perhaps more realistic (for me, three generations back was a brood of 8) the possible relatives jump to 60 million, and the chance of being related becomes 1 in 5! But of course our social circles are not random. I'd guesstimate that the pragmatic figure for most in the USA is around 1% of a shot that they're related within 6 generations, which is just about enough for anyone to recognize a common ancestor. If you're willing to count up to 10 or 15 generations, as the POTUS bloodline people do, you're raising the odds significantly.
what's the likelihood that the 2008 Republic and Democratic candidates will be somehow related
Different model required. For one thing, they often go all the way back. Ronald Reagan is related to every other POTUS because of his descent from the ancient Irish king Brian Boru, which was a millenium ago, and has to be roughly 40 generations back. At that level, you're going to catch practically everybody. Humphrys points out that we're all descended from Charlemagne, pretty much, and a slightly smaller chunk of us is descended from Muhammad -- including George Bush and John Kerry, most likely, because they have former British royal bloodlines and those come from Muhammad by way of Spanish royalty.
posted by dhartung at 1:17 AM on July 26, 2005
If you go back 10 generations, you have 2^10 N-grandparents, or 1024. If you merely assume they each spawned two children, on average (not likely for the earlier generations, but then again I don't know what the actual average is including terminal lines), you have 1024 * 1024, or 1,048,576. In the broadest sense, using this model, there's a 0.3% chance of being related within 10 generations to a random American you meet on the street. If the model assumes an average of 3 children, perhaps more realistic (for me, three generations back was a brood of 8) the possible relatives jump to 60 million, and the chance of being related becomes 1 in 5! But of course our social circles are not random. I'd guesstimate that the pragmatic figure for most in the USA is around 1% of a shot that they're related within 6 generations, which is just about enough for anyone to recognize a common ancestor. If you're willing to count up to 10 or 15 generations, as the POTUS bloodline people do, you're raising the odds significantly.
what's the likelihood that the 2008 Republic and Democratic candidates will be somehow related
Different model required. For one thing, they often go all the way back. Ronald Reagan is related to every other POTUS because of his descent from the ancient Irish king Brian Boru, which was a millenium ago, and has to be roughly 40 generations back. At that level, you're going to catch practically everybody. Humphrys points out that we're all descended from Charlemagne, pretty much, and a slightly smaller chunk of us is descended from Muhammad -- including George Bush and John Kerry, most likely, because they have former British royal bloodlines and those come from Muhammad by way of Spanish royalty.
posted by dhartung at 1:17 AM on July 26, 2005
This thread is closed to new comments.
posted by Gyan at 9:35 AM on July 25, 2005