YFull and TheYTree still use the older (longhand) nomenclature to some degree, even the designation of "A" at the top of the Y-DNA tree (now A-PR2921). The alternating system of letters and numbers, such as R1a1a, quickly became unwieldy and was replaced years ago by the modern (shorthand) method tht uses the first letter of the basal root (or haplogroup), followed by a hyphen, followed by the defining SNP. For example, A-M118 is now used instead of A3b2b.

Since YFull and TYT are included in the Open Y database, the old designations are placed on this table. Frankly I often state my own terminal haplogroup as R1a-YP4491 and would prefer to see the first three positions put back to use. It's just a bit more detail that researchers find useful. However, they're tabulated under R here.

Note that the counts refer to the number of basal haplogroups, not the number of SNPs.

A full list of the substitutions used by Open Y is found at https://ysnp.info/downloads/YF-translations.txt. Additional files are found in the Download Archive.