# The 7 times America was discovered



## Brian G Turner (Sep 11, 2022)

Seven times people discovered the Americas. How they got there
					

When Columbus landed in 1492, the Americas had been settled for tens of thousands of years. He wasn't the first person to discover the continent. Instead, his discovery was the last of many discoveries.




					phys.org


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## Swank (Sep 11, 2022)

And then there's the Chinese. Either in 1421 or 2800 years ago.


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## hitmouse (Sep 13, 2022)

I discovered the Americas in 1996, but I didn’t want to make a fuss about it.


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## Mr Cairo (Sep 13, 2022)

hitmouse said:


> I discovered the Americas in 1996, but I didn’t want to make a fuss about it.



I was there when you landed having just also recently discovered America but did not want to steal your thunder so stayed hidden .


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## thaddeus6th (Sep 13, 2022)

Swank said:


> And then there's the Chinese. Either in 1421 or 2800 years ago.


Could be wrong but isn't the 15th century claim based on a very popular book that has since been debunked?


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## Swank (Sep 13, 2022)

thaddeus6th said:


> Could be wrong but isn't the 15th century claim based on a very popular book that has since been debunked?


Yup. But there are other 15th century claims besides Gavin Menzies. Dunno if they have any validity.

However, Amerigo Vespucci ought to be credited as the first person to recognize America as a new continent(s) and get that fact to be accepted. Something Columbus didn't manage.


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## Parson (Sep 13, 2022)

I wonder about the claim that there might have been as few as 80 people from which the North American Indians descended. Doesn't that sound exceptionally low? How do you not suffer from genetic inbreeding? In a group that small there would likely be only 30 or so females able to breed at any one time. And then the almost certain large percentage of childhood death would mean that it would take a long time before the group reached any relatively safe level. Until then almost any kind of disaster would wipe this group out. Logic says that the group had to be 5 to 10 times greater than 80 to have any realistic chance.


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## Swank (Sep 13, 2022)

Parson said:


> I wonder about the claim that there might have been as few as 80 people from which the North American Indians descended. Doesn't that sound exceptionally low? How do you not suffer from genetic inbreeding? In a group that small there would likely be only 30 or so females able to breed at any one time. And then the almost certain large percentage of childhood death would mean that it would take a long time before the group reached any relatively safe level. Until then almost any kind of disaster would wipe this group out. Logic says that the group had to be 5 to 10 times greater than 80 to have any realistic chance.


80 individuals' genes, so maybe a group two or three times that size including everyone that didn't have surviving offspring. And some may not have survived due to inbreeding defects.

Inbreeding isn't horrible if there aren't a lot of bad recessives. All cheetahs in all of Africa can serve as tissue donors for each other. Which means that they all have the same weaknesses if their environment changes (like a disease).


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## Brian G Turner (Sep 14, 2022)

Parson said:


> I wonder about the claim that there might have been as few as 80 people from which the North American Indians descended. Doesn't that sound exceptionally low? How do you not suffer from genetic inbreeding? In a group that small there would likely be only 30 or so females able to breed at any one time. And then the almost certain large percentage of childhood death would mean that it would take a long time before the group reached any relatively safe level. Until then almost any kind of disaster would wipe this group out. Logic says that the group had to be 5 to 10 times greater than 80 to have any realistic chance.


I don't know about the specifics, but early societies tended to be very mixed, with either all the women or all the men being from completely different tribes, depending on whether the culture was patrilineal or matrilineal. So the genetic base could be very mixed indeed.


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## hitmouse (Sep 14, 2022)

Parson said:


> I wonder about the claim that there might have been as few as 80 people from which the North American Indians descended. Doesn't that sound exceptionally low? How do you not suffer from genetic inbreeding? In a group that small there would likely be only 30 or so females able to breed at any one time. And then the almost certain large percentage of childhood death would mean that it would take a long time before the group reached any relatively safe level. Until then almost any kind of disaster would wipe this group out. Logic says that the group had to be 5 to 10 times greater than 80 to have any realistic chance.


It is possible, but yes, limited gene pool is an issue. It seems reasonable that if a single group of 80 could cross over the Bering straight, multiple separate groups would have followed the same track over the millennia, so whilst the gene pool might not have been as limited as all that. We would not know about groups that died out.

Presumably there has been genomic analysis to back up these assertions.


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## Swank (Sep 14, 2022)

hitmouse said:


> Presumably there has been genomic analysis to back up these assertions.


I believe the assertions are entirely genomic. No one is claiming to know how many people crossed the Strait, just that they can only identify 80 distinct sets of origin genes in the Native American gene pool that survived the crossing and several generations of reproduction. There could be fairly large groups that lasted hundreds of years in isolation from other native groups before they were wiped out. And we wouldn't know about them unless we stumbled upon their remains. Those 80 are just the winners in the race to get your genes into the future.


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## hitmouse (Sep 14, 2022)

Swank said:


> I believe the assertions are entirely genomic. No one is claiming to know how many people crossed the Strait, just that they can only identify 80 distinct sets of origin genes in the Native American gene pool that survived the crossing and several generations of reproduction. There could be fairly large groups that lasted hundreds of years in isolation from other native groups before they were wiped out. And we wouldn't know about them unless we stumbled upon their remains. Those 80 are just the winners in the race to get your genes into the future.


Yeah. What it really means is that there were about 80 early individuals whose genes successfully propagated through those of the multitudes of others in the Americas. Not just 80 individuals who produced a progressively consanguinous,, inbred population.


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## Swank (Sep 14, 2022)

hitmouse said:


> Yeah. What it really means is that there were about 80 early individuals whose genes successfully propagated through those of the multitudes of others in the Americas. Not just 80 individuals who produced a progressively consanguinous,, inbred population.


I'm not what you mean. There were no "others" in the gene pool.

Unless you're talking about later migrations, like Polynesians into South America.


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## Aquilonian (Sep 15, 2022)

In conditions of high infant mortality, the great majority of people do not leave any descendants beyond the second or third generation. So if genes can be traced from 80 people among the original "Native American" colonists, then the total number who crossed the Bering Straits would have been very much larger than this.

Having said which, people can get away with a lot of inbreeding before it gets really damaging. Consider for example the population of Pitcairn Island, descended from 27 people (9 European and 18 Tahitian) who arrived in 1790. There were 15 men total (9 European and 6 Tahitian), but today only 12 surnames, only one of which is Tahitian. There are 16 Warrens, descended from a later arrival in 1830, and 15 Christians, descended from Fletcher Christian the leader of the mutineers. 

Of course the Pitcairn settlers had plenty of genetic diversity to begin with, being of two very different races.


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## LordOfWizards (Nov 4, 2022)

The topic gets me wondering - Why would any 'tribe' go that far north, suffer the indomitable winters, and survive. I'm guessing they were chased out of their homelands.


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## Parson (Nov 5, 2022)

LordOfWizards said:


> The topic gets me wondering - Why would any 'tribe' go that far north, suffer the indomitable winters, and survive. I'm guessing they were chased out of their homelands.


I suspect that what's going on here is a very, very, slow migration (think 100's or 1000's of years) where the difference of 50 miles or so a generation doesn't make that much of a difference, and only some of the moves were north.


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