Board Thread:Naruto Discussions/@comment-945885-20140709082448/@comment-1894786-20140718055945

Elveonora wrote: Just because they didn't manifest doesn't mean they weren't in his chakra.

Exactly. Both Naruto and Tsunade are two of the few Uzumaki's still alive and they're both blonde, when the handful of other Uzumaki's (Kushina, Karin, etc.) are all redheads. Just because those two are blonde, doesn't mean they're not Uzumaki's.