[defrost]

One question raised by a researcher in the article:

    Dr. Skoglund also said it would be strange for non-African ancestors to have arisen about 47,000 years ago while modern humans in Asia and Australia dated back 100,000 years. The sites in question could have been incorrectly dated, he said, or people could have reached Asia and Australia that long ago, only to die out.

Doesn't mesh well with genetic studies from Australia that show a long history of relatively stable regionalism within Australia (with some still unresolved mixing from Denisovan ancestors.

see:

(2016) https://www.abc.net.au/news/science/2016-09-22/world-first-s...

(2017) https://www.nature.com/articles/nature21416

etc.

[jltsiren]

The actual results in papers like these (both the paper in question and the ones you refer to) are typically of the form: "We sequenced these genomes. Then we took the noisy data, made a lot of assumptions, and applied statistical magic to estimate that the populations split approximately X generations ago. We interpret that as Y years ago." Everything beyond that is interpretation, not the result.

Such results are inherently noisy and subject to assumptions. The further back in history you go, the less accurate and reliable the results will be. Ancient DNA comes with its own issues and assumptions, but it helps with the accuracy of the results. Instead of trying to infer something that happened thousands of generations ago, you may now be only hundreds or even tens of generations from the split.

The clearest way forward would be sequencing Aboriginal Australian DNA from tens of thousands of years ago. Then you could get a more accurate estimate for the split between that population and other sequenced ancient populations.

[naijaboiler]

my own theory. Depending on cyclical geography limitations, humans have been forever moving out of Africa sporadically, going way back to Neanderthals and possibly even before. It wasn't just one wave, it was multiple waves from time to time.

The people that ended up in Australia were some of the earliest anatomically modern humans that successfully made the trip out and for some reason or the other were not really able to colonize Europe/Asia and kept venturing south until they ended up in Australia

Other later waves probably made it to the middle east and went back. Some made it a bit into Europe and some of asia. But it wasn't until relatively recent times, that we got waves that finally got a foothold in Europe/Asia and eventually outlasted other homo species that had dominated those areas for a 100,000 years.

I am not an anthropologist. I can't prove anything I wrote. I am just using my own common sense and the evidence that has so far been published.

[defrost]

> and for some reason or the other were not really able to colonize Europe/Asia and kept venturing south until they ended up in Australia

Any people that did settle in Europe to the north during that first pass through further south some 70K years ago very likely were pushed back by the worsening conditions preceding the advance of the Last Glacial Maximum (dry very dusty air, poor vegetation .. and later ice everywhere).

Following the path of best land with least resistance led to following the tropics mostly by land, consistent year round conditions, no winters to store food for, etc.

[withinboredom]

I wonder if this migrate-and-survive is a "great filter" that organisms must do in order to grow. The same thing will likely happen to space colonists, many will go, but only a few will survive.

[robwwilliams]

The dating of the fossils is quite secure. So in this dimension all is good. The DNA sequence is as good given the number of closely related individuals.

Your comments do not apply with any force to this particular study.