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I saw an episode of Nova years ago where dna analysis showed as few as 70 people crossed the Bering land bridge and formed the basis of all Native Americans.
https://www.livescience.com/289-north-america-settled-70-people-study-concludes.html
Now they’re pretty sure that people used boats and skirted the coastline but didn’t walk.
This is a great video about human migration to the Americas https://youtu.be/UsnrdCdGs7o
As few as… likely meant anywhere from 70 to 7000. The ranges on such predictions are usually very wide. Also, sure, 70 people could get lucky and not get wiped out. But the odds are strongly against them.
That article’s over 20 years old—I’m not up on the latest findings, but I know there’s been major work since then on both the peopling of the Americas and on the importance of genetic diversity.
It’s the other way around. It was once believed that a population of hundreds were needed but the DNA evidence proved it to be much smaller. If you have newer information that shows the DNA work done was wrong, please post it because I’ve been pulling out this trivia for years.
https://en.wikipedia.org/wiki/Genetic_history_of_the_Indigenous_peoples_of_the_Americas
Don’t know about the DNA but White Sands Footprints were dated over 20,000 years old, someone arrived before land bridge was available.
General rule in wildlife biology 50/500. Need 50 individuals to prevent extinction, 500 to have potential to evolve/survive threats.
Here are a couple papers that say those numbers are too low but I don’t have access to free copies. Second one a little beyond my understanding.
https://www.sciencedirect.com/science/article/abs/pii/S0006320713004576?via=ihub
https://www.sciencedirect.com/science/article/abs/pii/S0006320706002126?via=ihub
Hmm… the only cited sources in that article for a specific (effective) population size are also over 20 years old—the more recent sources just say it was likely a “small” number.
This article has a lot more detail on the various migration theories, but refrains from any specific size estimates:
https://en.wikipedia.org/wiki/Peopling_of_the_Americas
When research is old without being found wrong, it is more likely to be correct.
Lots of truth to that but not a lot of grant money available for replication research. After initial peer review might not get revisited for a long time.
Along with other bottlenecks once thought to be humans on the brink of extinction, like with the Toba eruption, further research tends to find other evidence to reverse the extreme nature speculated on. We do on the other hand have evidence of other species that had bottlenecks caused from disasters and the genetic signs are very obvious. Cheetahs as an example.