Thought for The Day - Genealogy

I was thinking about this today, and I did some calculations. Here they are:

Consider a problem of genealogy. How many people in the past are you related to?

Unless you are a product of cloning (not something we need to worry about in the past), you have two biological parents.

Each of your parents had two biological parents. So whilst you have two parents, you have four grandparents.

Each of your grandparents also had two parents, so you have eight great-grandparents. And so it goes. The number of people you are directly descended from doubles with each generation you go back.

2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048… and so on.

If we consider a generation to be the time it takes for a person to be born, grow up, and produce children of their own, then nowadays it’s probably around 20 - 25 years on average. If you study history at all, you’ll find that 150 years ago, particularly amongst labouring people, that figure was nearer 16 years - but we will err on the side of caution, and call a generation 25 years.

Doubling every 25 years, by the time we get back 30 generations (only 750 years), each of us is directly descended from 1,000,000,000 different people. Now that’s a bit of a problem, because the best estimates available suggest that the population of the whole world at that time did not exceed 450 million.

750 years is not such a long time. 750 years ago, the French were busy founding the Sorbonne, Oxford university had been teaching for 100 years, and Cambridge for 50. The crusades were still ongoing, and Genghis Khan’s mongol army were causing trouble in the east.

Now reverse the process. Imagine a young married couple in the year 1250. Let them have 2 children (in fact, 10 or 12 children were not uncommon in those days - yes, many died, but many did not), we’re being cautious. Two children per couple, and 25 years per generation.

Each couple has two children, but each child goes on to have two children… and on, and on… doubling each generation.

We get the same figure. Every person alive in 1250 A.D. now has 1,000,000,000 living descendants.

Bear in mind, the figures I have given account only for direct descendants. They take no account of other blood relatives - brothers, sisters, cousins, aunts, uncles etc. If you include them, you can probably multiply the figures by 10 per generation.

My conclusion? Genealogy is nonsense. You don’t have to go back very far at all, and you reach a point where everybody is related to everybody else. We’re all family. Really.


Thank you cousin.

I would say that geneology matters only to a certain point. My parents, grandparents and greatgrands are about as far back as I care to go. Tracing our roots is about feeling connected. At a certain point, we no longer ‘connect’ on the same level. Those people seem more like strangers. I mean, 2nd cousin is legal for marriage, though not looked upon with a lot of acceptance.
My dad was born in 1923 and quite a bit older than my mom so it gives me a connection that goes back in time further than most my age. Past my great grands though, and I don’t really feel that connection anymore. If I were to meet my great grands, it would be like 2 worlds colliding. She was Choctaw and died in 1930. He was English and died a few years before.
So yes, I agree. We reach a point where it really no longer matters, for a number of reasons.


And thank you, half-sister seven times removed.

I was only really considering the genetic links. Family history is another matter. Although when you look at the Cyril Burt studies, that opened up a whole other can of worms. Ask me about that some time.

It has long amused me when people trace their family tree, and find that from a marriage in 973 A.D. they’re related to King Draino The Malodorous - when, statistically, we’re all related to Draino. And Henry Vlll, and Julius Caesar, and if you trace the viking connection back far enough, we’re probably all related to Geronimo, too.


So we’re all inbred…could explain a lot.


Wait, surely not all different people? There must certainly have been a lot of overlap in the human family tree.
Your cousin has a set of grandparents and more cousins whom you don’t even know (ever think of that? It’s weird :laughing:), and their family tree overlaps yours.

I agree with that. :slight_smile:

The worst thing currently is these dubious webpages that collect (and probably resell) genetic samples in return for giving you an analysis of your past. A friend did one and she didn’t even know how to interpret the “results”. They send you something like (made-up example) “35% English, 18% French, 60% German, 24% Italian“ and you ask yourself: So, are 35% of my past ancestors from England? It doesn’t even add up to 100%. Or am I genetically similar to 35% of today’s Englishmen (meaning, both our ancestors may have emigrated from a common unspecified place)? Those would be two very different statements.

Then, the person in question was Swiss, and Swiss ancestry wasn’t even an option, she just gets German+French+Italian, who would have thought! Why spend money to be told such wisdom in the middle of Europe. :stuck_out_tongue_closed_eyes: And now she’s looking for the secret Englishmen in our family book? :expressionless:

It gets dramatic when someone is accused of being a “cuckoo child”. Or someone realises they are adopted, or actually the child of another relative… But we’ll get used to that after it happens often enough. :wink: Maybe the automatic disclosure will make people more honest and less judgemental……?

And that’s just for Europe where we have a lot of data and only a fixed number of countries for the mixture. Now, the Americans come in and are rightfully curious about where their ancestors are from. (One of my colleagues for example knew he was part African, part native American, but which peoples exactly?) You guys must get even more meaningless results…?

And, is it true that American law enforcement has used these services to find relatives of someone’s genetic samples found at the crime scene, and then looked at their relatives IRL, until they found one that matched the wanted subject? So, on that first level, we are already no longer in control of our own genetic data, because any random cousin could inadvertently “tell on us”.

It’s too late to stop genetic analysis now, since also a lot of good will come from these studies, such as tailor-made drugs that actually work. But we should also expect a lot of Schindluder (getting skinned like an animal’s cadaver - sorry, this metaphor says it best). Even today teenagers get flooded with personalised ads targeting their insecurities. Next they’ll hear “you’re genetically predisposed to be < insert synonym of dumb or ugly here >, buy these pills!” They’ll need to steel themselves for that.

— AdaRynin who is most certainly related to Archilochus!!!11 :wink:


Well, there was a lot of overlap in the Habsburg family tree alone, so I would tend to agree with that conclusion… :rofl:


You know the bit where I pointed out a problem? This bit:

That’s exactly what’s going on there. There’s a huge amount of overlap and double counting going on. Then again, I only stopped at A.D. 1250 because the numbers became ridiculous after 30 generations. If you really wanted to get a true picture of the complexity, you could justifiably extend the calculations back another 60,000 to 70,000 years, but what would be the point?

That’s what I was referring to when I mentioned the Burt studies. It’s interesting, but long. I will write a little note, and post it later. :grinning:


So a funny thing happened when these genetic tests became available. There are agencies which infiltrate hate groups so they can monitor their activities. They reported the following. Many in these groups rushed to prove that they were 100% European…then they started getting the results…a few accepted the results and it changed their viewpoint on race. Others simply hid the results. Some, however, invented conspiracy theories like, Jews had tampered with the tests…not sure there is a moral to the story but, it seems these tests can possibly have a positive affect on some people. Others, well, they would rather shrink the gene pool…no matter the results.


Right on, bro! U da man!


I don’t see how that works. These people must have been under two fundamental misasumptions, which is a) Humanity originated in europe, and b) that “european” is even a thing. The second one seems to kind of suggest that we’re talking about americans here, because an actual european doesn’t identify as european, except politically, and then they’re left-leaning…
I’ve noticed a tendency in americans to forget that europeans are killing each other most of the time, just because the major nations have managed to kind of get along for 80 years (well, at least until a couple months ago. And only if you count the cold war as “getting along”…).


European = white (in their minds)…we are talking hate groups. But, as we see in @Polyphemus discussion here, none of us 100% anything, except human…maybe… :alien:
To clarify, the results showed that many of them had African ancestry. Which, we all do since the great genome mapping that was carried out worldwide seems to indicate we can all trace our roots to the African continent.


:rofl: I guess… I remember the moment I finally realised that “white” and “black” do not refer to skin color at all, but just ancestry. It was when the whole thing with that british prince (… henry? Possibly? I have no idea anymore, honestly!) proposing to his canadian girlfriend (forgot her name too, actually, and too lazy to google) made the round in the news.
And someone, somewhere was like “OMG what if england got a black queen”, to which my first reaction was not “Oh, that couldn’t happen because succession etc.” but instead “how… how is she black? She’s not black. I have a nephew that was adopted from Togo, he’s black. If she’s black, then what the hell is half of europe during summer?”

Well, everybody does. No need for a gene test or anything for that. It’s pretty well known that Africa is the place where certain apes first started hitting each others with sticks.


World history is a constant catalogue of movement and migration. Either by peaceful settlement, or violent invasion, people have steadfastly refused to stay put and remain racially pure.

Consider the Roman empire. 2,000 years ago, the Romans controlled most of Western Europe, North Africa, and Western Asia. They enforced their rule through the use of armies called Legions.

Rome itself was tiny compared to the empire. The Romans couldn’t possibly recruit enough actual Romans to man the legions, and they didn’t try. Instead, they recruited soldiers in the lands they conquered.

The Romans were not, however, stupid. They recognised that it was a bad idea to have soldiers fighting in the same country they were recruited from. They might have to fight against their own tribe, or even their own family. The risk of divided loyalties, refusal to fight, desertion, or rebellion, was too great.

The Romans got round the problem by recruiting legions in one country, but sending them to serve and fight in another. It was very common, particularly in trouble spots, for legions to be foreign to the country in which they served.

Roman soldiers would serve for 20 years. At the end of this period, they would be given land to farm, and a small pension. As the Romans recruited soldiers from the age of 14 upwards, it was possible for some to retire as relatively young men. Most retired Roman soldiers would settle in the areas around their last garrison, and, crucially, many of them married local women, and raised families. Tribal women seem to have considered a retired Roman soldier quite a catch as a husband - he was (to a degree) educated, he had land, money, status, and, with luck, he bathed regularly.

Let’s consider a very specific example. For 300 years, the northernmost boundary of the Roman Empire was Hadrian’s Wall, which separated the land of the Britons (Britain) from the land of the Scots (Scotland). For 300 years, the Wall was manned by legions and cohorts drawn from all over the Roman Empire. And when those soldiers retired, they set up homes, farms, and businesses. They married local women, and raised families. Over time, their children and grandchildren just blended in with the local population.

Now most of the Roman legions stationed on the wall were arguably “European”. They were drawn from places that are now in Holland, Belgium, France, and Spain. But some were decidedly not European. There was at least one cohort of 600 men from Syria. There was another, also 600 men, from North Africa. The fortification at Arbeia (now South Shields) was manned by Iraquis. And these men eventually just intermarried with the local population.

I use Hadrian’s Wall as an example, not because what happened there was exceptional, but because the evidence of what happened there has survived. We can reasonably assume that the mixing and intermarriage of nationalities was going on all over the Roman Empire. It’s just that parts of Hadrian’s Wall are now so remote and isolated that buried evidence has not been destroyed by modern development.

Much of the modern United States was settled by people from Britain. That’s why they speak English now. Some of them seek to convince us (and perhaps themselves) of their pure British ancestry. Unfortunately for them, you could not have a more mongrel mixture than the British.


See, other parts of the world seem to understand that…here in America…not so much. Culturally bereft, it is hard for some to see past the founding of the country. As if that was the beginning of humankind.


Bathing was actually very common throughout all of history and all cultures. I have no idea where the weird idea that it’s a more modern invention even comes from. I guess like most of european historical revisionism it comes from the late renaissance up into the victorian periods, where there seems to have been an above-average desire to feel smugly superior over ones ancestors…


Weren’t Roman baths known as centers for philisophical discussion?


“Where are those bubbles coming from, Cicero?”