Yes. But let me give the correct explanation.
The expression starting with "which" begins a non-restrictive phrase (not a subordinate clause). A non-restrictive phrase or clause (1) renames something or (2) provides an additional description that is not necessary to distinguish the thing from similar things--meaning it is unnecessary for understanding the point of the sentence.
All non-restrictive phrases and clauses are set off from the main sentence by commas. Thus, in this case, you need the comma before "which."
Another example of a non-restrictive phrase is "I just heard from my father, who is in Borneo." The non-restrictive clause is "who is in Borneo," and it is correctly set off from the main sentence with a comma.
"Unlike white" is, indeed, a parenthetical expression and is correctly set off with commas.
For more on commas with "which" and non-restrictive phrases and clauses, you might check out "A Cauldron of Commas" (comma use two): http://zencomma.wordpress.com/2011/10/04/a-cauldron-of-commas/ and "That vs. Which": http://300daysofbetterwriting.wordpress.com/2010/04/12/that-vs-which/ .