Large ancient-DNA study uncovers population that moved westwards 4,500 years ago
nature.com
nature.com
The actual news story seems to be that we've finally found DNA evidence that backs up the archaeological and linguistic indicators we've already had. The rest is just providing context while somehow managing to present the concept itself as novel (which it isn't).
This is akin to starting a story about cosmic background radiation being discovered with the headline "Origins of the universe linked to rapid initial expansion". Yes, the discovery itself is newsworthy, but the headline would lead you to believe that the theory itself is somehow novel or unexpected.
With people walking a few hours between villages, ideas could theoretically spread at >10 kilometers a day. At 100 walking days a year, that's Rome to Paris in a year, easily. In practice, transmission speed would be way lower, but given a few millennia, a lot is possible.
And, by the way, that applies to genes, too. There is no need for statistical east-west drift of humans for genes to spread from Asia to Europe. All you need is (way) more people in Asia than in Europe, and people moving a few km in random directions between birth and adulthood (oceans limiting such movements would help, too, but aren't even necessary)
You needed a lot more than a few hours to walk between the villages in the Eurasian steppes, mostly because there were no villages there.
Population density back then wasn't what it is now.
http://arheologija.ff.uni-lj.si/documenta/pdf30/30richards.p...
I always found the Black Sea Deluge theory interesting....
http://en.wikipedia.org/wiki/Black_Sea_deluge_hypothesis
There is some speculation that this flooding event was part of the impetus for the initial dispersion of the Indo-European from the area. In the Bible, it is claimed for instance that after the flood, the ark came to rest on the mountains of Ararat, (south of the Black Sea in modern Turkey). Maybe this story and other flood myths (like Gilgamesh) were been carried by refuges from the event into their new homelands....
It would be extremely interesting to go back in time and watch these events unfold in fast forward.