According to DNA Analysis, Vance DNA Group 2 is one of the youngest genetic "sub-clusters" of Vances; with a MRCA (most recent common ancestor) somewhere around 300-400 years ago. It consists entirely of about 10 immigrant lines into the United States in the 1700s and 1800s whose connections have not yet been proven but whose origins (where known) appear to be Protestant Ulster (Irish) families. Most of those Protestants came to Ireland from Scotland in the Plantation of Ulster which began in 1609, although immigration into Ireland from England and several European countries was also common.
Their closest match in the other groups is DNA Group 1, but based on current analysis the two diverged from each other roughly around 320 A.D., so before the time that surnames were common. As the Group 2 report (available on the previous page) notes, "this indicates a very low probability of a common descent within a genealogically meaningful timeframe" (although this means a common genetic descent; how their surnames evolved is still unknown).
The immigrant lines in Group 2 who can trace back to Ireland land in Ulster (Donegal, Tyrone, and Fermanagh), making these Vance families close neighbors with the Vance lines from Groups 1 and 3, among possibly others. How these various Vance lines evolved, however, is still being researched.
The most work on the various Vance lines in Ulster and how Group 2 might fit in with those has been done by Marilyn Vance McGaughey and is available in this PDF:
Surname Vance 2a Family Origins