Stone Age settlers migrated across Europe in multiple waves that replaced older hunter-gatherer cultures with the genes from each wave blending into the population of the day. Ancient mtDNA studies are revealing that cultures spread to a great extent by the physical migrations of peoples and possibly faster and more effectively than by cultural diffusion alone. And the many different gene-melts continue today. Whereas in the Stone Age much of the action was in Central Europe, in the jet-age the melting-pots have shifted westwards and are mainly now in Western and Northern Europe. The peopling of Europe is an ongoing thing.
Guido Brandt, Wolfgang Haak, Christina J. Adler, Christina Roth, Anna Szécsényi-Nagy, Sarah Karimnia, Sabine Möller-Rieker, Harald Meller, Robert Ganslmeier, Susanne Friederich, Nicole Nicklisch, Joseph K. Pickrell, Frank Sirocko, David Reich, Alan Cooper, Kurt W. Alt and The Genographic Consortium, “DNA reveals key stages in the formation of Central European mitochondrial genetic diversity,” Science doi: 10.1126/science.1241844
… the people who lived in Central Europe 7,000 years ago had different DNA lineages than those that lived there 5,000 years ago, and again different to those that lived 3,500 years ago. Central Europe was dynamic place during the Bronze age, and the genetic composition of the people that lived there demonstrates that there was nothing static about European prehistory.
Genographic Project Director and National Geographic Explorer-in-Residence, Spencer Wells expounds: “spanning a period from the dawn of farming during the Neolithic period through to the Bronze Age, the [genetic] data from the archaeological remains reveals successive waves of migration and population replacement- genetic ‘revolutions’ that combined to create the genetic patterns we see today.”
What we see in Europeans today is a kind of mixture of what was present there at different times in our past. So, just like parts of Europe today are melting pots from different living cultures across the world, Europe is also a melting pot of genetic lineages from different prehistoric cultures that lived there at different periods of time.
Dienekes: “Central Europe, once populated exclusively by hunter-gatherers, experienced a virtual disappearance of their matrilineages for almost two thousand years after the advent of farming. Then, between the Middle to Late Neolithic, around five thousand year ago, the hunter-gatherers make their re-appearance before their lineages converge to their modern (minority) frequency”

