What kinds of dogs have this hair???

[SunGurl372]

I'm wondering what dog breeds would have hair that is actually two-toned. I don't mean two different hair colors growing in the same coat. I mean two different hair colors on each STRAND.

For instance, pluck a one inch long strand of hair and the bottom half-inch, closer to the skin, is white, and the top half-inch is black. In some instances the bottom half is also tipped in black (so the whole length would go black-white-black).

Also, I was wondering if all dogs have "hackles"? I'm not sure that is the official term for it, but its what I call the ridge of hair along the spine that stands straight up from shoulders to tail, usually when the dog is aggressive/protective/scared (ie. experiencing extreme emotion).