David Reich on Indo-European Genetics

Some updates on what the science is telling us, from this lecture, on YouTube. First, Yamnaya – the Ukrainian people who spread Indo-European languages across Eurasia – took form around 4000 BC. They mainly migrated from the east, from the Don River basin and the northern Caucasus, but interbred with local hunter-gatherers. They were not numerous, only a few thousand people. They lived around the lower reaches of the Dnipro River.

Then around 3600-3400 BC they exploded in numbers, a "classic founder event." (Founder events are when a few people reach a new environment where they multiply enormously, like the New England Puritans or the first French Canadians.) Around 3500 BC is when we first get good evidence for wheels, and Yamnaya skeletons show evidence that they rode horses. So it looks like the Yamnaya had by 3500 BC perfected both horse riding and cart-building and launched themselves onto the steppes as nomadic herders. They were very successful and soon there were hundreds of thousands of them.

Then around 3200 BC they launched themselves into the world so rapidly that their expansion "broke the connection between geography and genetics." All the samples shown on the map above are just Yamnaya, genetically from the same population.

One of the big remaining questions in all of this is where the first Indo-European languages arose. Reich points to the North Caucasus as the likely homeland.