Humanity's Common Ancestor Only ~3500 Years Old

[chequita guevara]

Originally posted by notyoueither
There were barriers to interbreeding that were as much cultural as based on distance, maybe more.

There were barriers to peaceful interbreeding. Captives were often taken and made into wives, children taken and raised as your own, etc.

Also consider that most people in North America who call themselves Indians today are at least partly white. It's possible some groups got introduced to the 'family' later rather than earlier.

[MikeH]

Originally posted by Chemical Ollie
Using a mathematical model that ignores imbalances in global migration and breeding patterns would get a result like this. I don't want to spend my whole coffe break to find out which model they have used, but I'm sure it's more complicated than the one MikeH showed.[/b]

Of course. I'm just showing the kind of scale of population that one person could produce at a relatively slow rate of breeding. After about 1000 years his potential descendents are so much larger than the population of the planet that even if there is only a tiny amount of migration and interbreeding with other populations the relationships would be passed on.

The only controversial thing is whether any group of humans were alone and not interbreeding in the past 3500 years, if even one of the common ancestor's descendent came from outside a remote group and bred with them the dna strand would be part of the whole population within an amazingly small number of generations.

[lord of the mark]

To work out how much different groups of humans mingled, Rohde's team simulated the rates at which a few pioneering people made journeys across the world to meet and breed with other populations. Their model gave each individual a certain probability of quitting their home town, country or continent and striking out for pastures new.

interesting - they modeled migratory behavior - could have used economic models, biological models, or perhaps anthropological models. The question is how did the assumptions in this model match actual historical behavior of the most likely source of old world genetic material into the americas, the inuit? How was the model validated? Surviving neolithic populations? Would these match actual new world conditions 1000 to 3000 years ago? Animal migrations? can these be extrapolated to neolithic humans?

[Japher]

Interesting... Probably not true. I don't think they made all the right assumptions, but using the number of assumptions they did that is quite a feat of organizing "randomness"

[Sandman]

I'm sceptical, for reasons others have stated. Their claim that ALL humans have a common ancestor 3500 years really sounds far too strong, given the isolation that many segments of the world had until recently. New Guinea is one example, and remember that the Incas and the Aztecs had no knowledge of each other's existence, so presumably trans-American interbreeding was pretty minimal.

Also, just because every person COULD have however many ten to the nth ancestors/descendants doesn't mean that they did. Inbreeding and assorted barriers could have easily limited the spread of descendants of this mythical person, and such limitations could easily occur for everyone alive 3500 years ago.

For simply Eurasia, it's not quite so unlikely, given the profusion of expansionist peoples which have shaped its history. But Africa and America... nah.

[Japher]

They also had to assume migratory patterns, which are obviously way wrong considering the proven existence of isolated civilizations prior to that time.

[Al B. Sure!]

For simply Eurasia, it's not quite so unlikely, given the profusion of expansionist peoples which have shaped its history. But Africa and America... nah.

likely true for Eurasia and N. Africa as people got around quite a bit and every civilization in that area had at least vague knowledge of the existance of other civilizations on the other side of the continent... traditional history claimed bronze age Egyptians, Mesopotamians, Indians, and Chinese were oblivious to each other, but since the 1950's, this has been disproven and it was found there was a great deal of contact and trade between the Egyptians and the Indians for example.

its also likely that this holds true for Africa as Africa had perhaps the most migratory people ever: the Bantu. As diverse as african cultures are and as diverse as their languages were in 1 AD, almost all of them speak a Bantu-derived language now and this has been true for centuries. I bet the Bushmen, pygmies, and a few others remained isolated, but the Bantu got around quite well and the areas where Bantu-derived languages don't dominate (Ethiopia, Somalia, etc.) were at the border of the ancient crossroads of civilization so they are clearly of mixed race

for the americas, though... i'm sure all american indians were descended from the same handful of people who crossed the strait 40K-10K years ago, but not as recently as 3500 years ago... that's crazy.

[Sandman]

Oh, yeah, forgot the Bantu. Although their contact with the rest of the world was patchy until the Arabs turned up, which might not have been long enough for a common ancestor to work its way right through Bantu lands.

[Al B. Sure!]

Sandman, yeah. they got around quite a bit and completely wiped out all previous African peoples (kind of like the indo-europeans into Europe) but they had very limited contact with the rest of the world after that... i mean the whole thing is conceivable that some Egyptians bred with some Sudanese who in turn bred with Ethiopians, who did it with Somalis who did it with the Zanj... and so on but i dont think that could possibly have as great an effect.

[GePap]

Originally posted by Albert Speer

for the americas, though... i'm sure all american indians were descended from the same handful of people who crossed the strait 40K-10K years ago, but not as recently as 3500 years ago... that's crazy.

Thats not what the model says-the model is not saying there was one common ancestor 3500 years ago- its saying you would have at least one common ancestor with every human being living on the planet if you and them searched your family trees far enough back, and that by the time you reached 1500 BC you would have found one common ancestor with everyone else.

How would this work with the Americas?

Well, first, most Native American populations were killed off. So talking about the remants, the idea is that along the line, in the heritage of any of them, somebody walked in who was the decendent of someone born who had one parent from Eurasia-perhaps some native woman raped by a European, or a Zambo (slave mixed with Indian), or a meztizo, whatever.

[Mercator]

Originally posted by Sandman
(...) and remember that the Incas and the Aztecs had no knowledge of each other's existence, so presumably trans-American interbreeding was pretty minimal.

Which is obviously irrelevant, since this theory talks about the people today. How many Aztecs and Incas are there alive now, who haven't in some distant past "mingled" with Europeans?

Say, if that 3,500 year old Asian dude already was an ancestor of all Europeans, most of the Americas basically already come for free, with the exception of some really isolated tribes.

[Iskandar Reza]

If that's the case this entire 4 page argument is really a big stupid miscommunication. It's not difficult to imagine then. I mean in my case every 6th person I meet is somehow related to me by a common ancestor during the British/Portuguese/Spanish colonial era.

[GePap]

Much of the same arguement would apply to most Africans given that the Bantu migration wped out most non-Bantu populations in southern Africa.

The only possible outliers are trully isolated tribes, like in the Amazon, but even there some meztizo must have come by and done the deed with the local babes.

[Bugs ****ing Bunny]

I've just read page one of this thread. Though I was amused by Speer being as dumb as a sack of hammers, I was also disturbed by the suggestion that I'm related to him.

[GePap]

He might well be your second Cousin, 36 removed.