We recently got an interesting result in J2b-YP91, the rarer child lineage of J2b-L283>Z622.
By a la carte SNP testing at YSEQ, I found that a sample of ethnic German descent but unknown region was positive for J-YP91 and negative for the only known child, YP61. His ancestral surname is Reesman.
Later I helped them fund a WGS400 using my J-L283 Research Fund. The result is that he was positive for some SNPs at the J2b-YP91 level and negative for others. This was a pleasant surprise for our research into the geographic origins of this rarer child of J2b-L283>Z622.
This means that Reesman represents a distant branch of J2b-YP91 and that all the other guys in this line are more closely related to one another, now represented by the child branch J2b-YP153. You can see the newly discovered branch on the live version of the YFull YTree.
While Reesman doesn't have a paper trail to a specific region of Germany, his GD 3/67 and 4/67 STR matches trace descent to Oberallgäu, which is the part of Bavaria bordering Baden-Württemberg and Austria to the south. These mens' STRs are so divergent from others in our haplogroup, being over 4500 years distantly related to their next closest relatives established by SNP testing, that these STR matches are certain to be their next closest relatives.
Prior to this discovery, the most distantly related J2b-YP91 lineage to the rest were the Biebers from Hirschland, Bas-Rhin. So we now have two samples from approximately the same area north of the Alps representing the greatest diversity of J2b-YP91 so far.
All the other men, representing such diverse areas as Norway, Holland, Russia, England, Poland, Ukraine, Sardinia, Albania, Armenia and even Kamchatka, descend from just a single man, called the Most Recent Common Ancestor of J2b-YP61, who lived 1300 BC. He could only have been born in one of these places and likely it wasn't one of the most geographically divergent locations.
It'll be interesting to theorize on how some of these J2b-YP61 men's ancestors migrated to where they now trace their descent. Given the great geographic diversity I'll wait for more samples before thinking about this.
So sampling rates notwithstanding, we would expect that the J2b-YP91 Most Recent Common Ancestor, who lived sometime before 4500 years ago, would be more likely to have lived near the areas of greatest diversity, which we now see is just north of the Alps.
However, we should keep in mind that we are only basing this on two lineages. While we may confidently trace each of these lineages to the respective areas, based on their STR matches, we don't know how much earlier than the genealogical time frame the lineages had been established in the area. There could be other men related to these that were living somewhere else and had died out or just didn't test yet.
For instance we cannot rule out a coincidental co-migration to this area that may have taken place during the Roman Empire.
There is at least one more promising piece of information. There is a third man who is J2b-YP91(xYP61) with ancestral surname Baron who traces descent to an ethnic German living in Opole, Poland. If his deeper ancestor were in fact an ethnic German then he could be seen to corroborate a north of the Alps origin for J2b-YP91.
So a north of the Alps origin for J2b-YP91 is a theory that we can continue to evaluate in the light of more data, hopefully eventually to include ancient samples.
Math Stuff: How Diversity Can Be Computed
The Y Heatmap: Diversity Map that I recently developed computes relative diversity of a lineage across different areas. To calculate the diversity map for J2b-YP91, it would give the Oberallgäu sample equal weight as the sum of the samples below its sibling branch J2b-YP153. This is because sibling samples get equal weight.
By the same logic, the Hirschland sample would get equal weight to all the samples below J2b-YP61.
So the data points that go into the calculation count Oberallgäu as twice that of Hirschland, and all the samples below J2b-YP61 get a total weight that is equal to the Hirschland sample.
When the YFull tree is updated next, I'll add the Diversity Map to this post.