There must be some explanation somewhere on the FTDNA web site to explain this, but I cannot find it if there is one. The new format of Y-DNA matches includes a new column "Big Y-500 STR Differences" which is thus a genetic distance column. I clearly do not understand how best to interpret and use the Big Y-500 information. Comparing the prior and new genetic distance columns, some things do not make sense, which almost certainly means that my understanding of the Big Y-500 is flawed. 1 - Some Y-111 matches have a genetic distance that that is greater than the Big Y-500 difference. For example, one matching kit has a Y-111 genetic distance of 6, but a Big Y-500 of "1 of 442". And another is Y-111 at 5 and Big Y-500 at "2 of 437". I had thought that the Big Y-500 STRs included those in the Y-111 plus some more. If that were the case, then the Y-111 genetic distance would always be less than or equal to the number of differences in the Big Y-500. But clearly that is not the case. So what is the relationship of the STRs in the Y-111 test to those in the Big Y-500 STR results? 2 - The other thing that sticks out very noticably is that the closeness of matches at Y-111 genetic distance is sometimes the exact opposite of the number of Bug Y-500 differences. For example, three kits match at a Y-111 genetic distance of 3 (call it Kit A), 5 (B) and (6). But in the Big Y-500 STR differences, they are 5 (A), 2 (B) and 1 (C). How should I interpret and use this significant difference in order? And which order is the "real" order"?