Some of the major Y-DNA lineages in Europe are traceable to the early Neolithic era or are even older, while three others (specific subsets of I2, R1a and R1b) expanded at a breathtaking pace more of less simultaneously around the late Neolithic/Enolithic/Copper Age/early Bronze Age era. Once this major expansion was complete, the population genetic of Europe have mostly been fairly stable, with a few exceptions that prove the rule due to well documented historical events.
A new study provides a detailed analysis based mostly upon the diversity of modern Y-DNA lineages in Europe and their phylogeny, clearly sorts the two, while also providing useful corroboration from a nearly complete index of ancient Y-DNA finds, by haplogroup, in Europe in the relevant time frames.
The ancient DNA classified by the archaeological context of the finds, also provides strong circumstantial evidence regarding which Y-DNA lineages were associated with the pre-Neolithic hunter-gather populations of Europe. In sum, hunter-gatherer men appear to have been predominantly Y-DNA I1 in most of Europe and Y-DNA R1b and R1a on the Northern and Southern part, respectively, of the Russian steppe.
The remaining major European clades appear to have arrived with the wave of mass migration that drove the Neolithic revolution (i.e. the introduction of the farming and herding of domesticated plants and animals), although a very late Upper Paleolithic arrival (i.e. "Epipaleolithic" a.k.a. "Mesolithic") cannot be ruled out in most cases, and is established by ancient Y-DNA in others.