Haplogroup R1b (Y-DNA)
Eurasia is a continent or supercontinent comprising the traditional continents of Europe and Asia ; covering about 52,990,000 km2 or about 10.6% of the Earth's surface located primarily in the eastern and northern hemispheres...
, most likely in Western Asia. T. Karafet et al. estimated the age of R1, the parent of R1b, as 18,500 years before present.
Early research focused upon Europe. In 2000 Ornella Semino and colleagues argued that R1b had been in Europe before the end of Ice Age, and had spread north from an Iberian refuge after the Last Glacial Maximum
Last Glacial Maximum
The Last Glacial Maximum refers to a period in the Earth's climate history when ice sheets were at their maximum extension, between 26,500 and 19,000–20,000 years ago, marking the peak of the last glacial period. During this time, vast ice sheets covered much of North America, northern Europe and...
. Age estimates of R1b in Europe have steadily decreased in more recent studies, at least concerning the majority of R1b, with more recent studies suggesting a Neolithic age or younger.