Distribution Map
Note: Rox2 is a relatively young subclade (possibly c. 1300 years old +/- a few centuries).
The above map represents the place of origin of Rox2 matches made using hobbyist data. It is not a comprehensive Europe-wide study that samples early populations from all countries equally, it is more a loose representation of the locations of origin of those in the hobbyist DNA projects. DNA genealogy is a popular North American hobby and most FTDNA results are those from North Americans of relatively recent Irish and British Isles descent. When mapping modern hobbyist data it appears that Rox2 is mainly found in Ireland and the north of the British Isles, especially around The Borders region between Scotland and England. After Ireland, Scotland and the Border regions have the best representation in the hobbyist yDNA databases. Not all can point to their ancestor's earliest place of origin with certainty, some locations are speculative.
People migrated from some areas of Britain and Ireland in much greater numbers than others and at different times (link). The Highland Clearances and Potato Famine led to mass emigration. Parts of rural England and Wales experienced less emigration. Online yDNA 'heat maps' made using FTDNA hobbyist data tend to best represent the European regions that North American emigrants left over the last few hundred years (mostly Ireland, Scotland and the Scottish/English Border region). A similar effect has been noted by those of Italian ancestry - there is a bias towards Americans of southern Italian origins in the hobbyist databases. Comparatively few native Europeans take DNA genealogy tests as a hobby. The People of the British Isles project (published in Nature, 19th of March 2015) sampled people from many rural areas across the whole British Isles.
General patterns are still evident but the imbalance needs to be kept in mind when interpreting maps made using hobbyist data. Founder effects at certain locations, i.e. those made by more recently-living founders, can inflate the number of pins in a particular area. If there were no North American-born FTDNA results represented on the above map, the place of highest frequency of European-born Rox2 FTDNA matches would be northern Sweden - few British Isles/Ireland Rox2 matches were born in Britain/Ireland. The disparities are apparent if we compare the similar-sized populations of Yorkshire (5.3 million), Scotland (5.2 million) and Ireland (4.6 million) with the size of their respective FTDNA projects. FTDNA projects are the main source of data for the maps, above. In May 2017, Yorkshire, with a population that is larger than Ireland or Scotland, had only 144 members in its FTDNA project, many are not even from Yorkshire. The Scotland project had 9883 members, with 17000 kits at FTDNA listing Scotland as their place of origin. The Ireland project had 7611 members, with 22500 FTDNA customers list Ireland as their place of origin.
DF27 is not generally very numerous in Ireland or Scotland today, L21>DF13 is, but if medieval DF27 lineages like Rox2 were established and widespread in those places before emigration to British colonies, they show up well in the hobbyist databases. Sweden's population is c. 9.85 million and the FTDNA Sweden DNA project has 6675 members (November 2017), so it is well represented in hobbyist databases in comparison to other European countries. Considering the low number of Yorkshire kits in the database, Rox2 has a good representation there, including results from several NGS-tested kits. There are also intriguing matches from southern England that stand out from the large northern clusters.
A handful of other DF27>ZZ19 subclades stand out due to their size at the Big Tree. They are often the result of similar relatively recent (Early Medieval) individual DF27>ZZ12>ZZ19 founding events. Parts of England and continental Europe will probably contain similar-sized Early Medieval founding events but they are less obvious due to there being fewer representatives of those yDNA haplogroups in the databases. France is underrepresented due to a ban on DNA testing for genealogy in that country.
The relationship between yDNA subclades and historic 'tribes' is looking to be more nuanced than was assumed a decade ago. Over the millennia people have travelled widely, some of the archaeologically-tested Bell Beaker folk moved great distances in their own lifetimes. Migrations in the late Bronze Age, Iron Age and those of the later Migration Period mixed yDNA haplotypes yet again. In-depth analysis using ancient yDNA matches alongside TMRCA estimates and phylogenetic tree comparisons are needed to give an accurate indication of where a particular subclade was at a specific time and place in history.