Taco Cowboy writes "'While the distribution of Y-chromosome haplogroups in Africa took 12 thousand years to spread, those in Europe started from around 3rd millennium.' The speed of spread of the European haplogroups was totally astounding, to say the least. 'There was no R1b found in Europe before a Bell Beaker site from the 3rd millennium BC and today many Europeans (most in western Europe) belong to this haplogroup. 'We used coalescent simulations to investigate the range of demographic models most likely to produce the phylogenetic structures observed in Africa and Europe, assessing the starting and ending genetic effective population sizes, duration of the expansion, and time when expansion ended. The best-fitting models in Africa and Europe are very different. In Africa, the expansion took about 12 thousand years, ending very recently; it started from approximately 40 men and numbers expanded approximately 50-fold. In Europe, the expansion was much more rapid, taking only a few generations and occurring as soon as the major R1b lineage entered Europe; it started from just one to three men, whose numbers expanded more than a thousandfold.'"