23andme (version 1) gives a man's paternal haplogroup as j2a1b1*, which is equivalent to J-M92 (YCC 2002/2008 shorthand), according to the table Phylogenetic history contained in the article "Haplogroup J-M172" at Wikipedia. Family Tree DNA (Y-DNA 111) gives the same man's paternal haplogroup as J-M172. How should these differences be interpreted?
They are effectively the same result with different levels of granularity / detail.
There are a couple things to keep in mind in regards to Y Haplogroups in general and the four main things are to keep in mind are:
- Granularity / resolution of specific testing services and specific tests you purchase.
- The Y-Tree is currently being updated monthly as more people are tested and new discoveries are made.
- There are Y-STR tests (i.e. Y-37, Y-67, Y-111) and Y-SNP tests. SNP tests usually provide greater depth into your Haplogroup and Y-STR tests currently are better for Genealogical History Timeframe matching with distant ancestors.
- There is the older style naming convention used by 23andMe.com and Y-Search that worked when there were less branches and depth but with increasingly complexity and depth of results the shorthand version is now the standard and expects you reference the current Y-tree to find the placement of the shorthand in the larger tree.
The very high level J-M172 simply means = J2 which is a little surprising they only were able to determine J2 from a Y-111 ... but you would get a much more in-depth result from further SNP testing on there (even more than 23andMe).
The 23andMe Haplogroup group is based on Y-SNPs (not Y-STR) and provided a little further detail with j2a1b1* = M92, M260/Page14; which is probably similar as you would receive through a National Geographic DNA 2.0 SNP test processed by FamilyTreeDNA.
Looking at the J2 tree on YFull it means you belong to one of the many branches under J-M92 which you will only be able to further determine through SNP testing like the Big-Y test or a SNP pack; I would recommend also looking at my answer to this question which I have some further detail on this.
Your High Level is J-M172 (J2)->J-M410->J-PF4610->J-L26->J-PF5087->J-PF5116->J-L558->J-M67->J-Z500->J-M92->One of the SNP sub-branches.
There are currently about two dozen defined sub-branches under J-M92 and as more people do Big-Y tests more are likely to be defined.