In my ancestral neck of the woods, Nova Scotia, I have several records where my Dow family members are incorrectly recorded as "Due" on tax rolls and "Doo" on baptismal lists. I am not mistaken-they are definitely the same people. Since the name is traceable (in Scotland anyway, to Robert Dhu, this is most likely how my ancestors pronounced it in 1800). In England, where V and W were interchangeable, Dow certainly could be turned into Dove. And if it could also be pronounced Doe, then Dough is not so far off either.