@GrandTardigrade said:

SPOILER

We know that Jon probably has Targaryen lineage. It just occurred to me that this is perhaps subtlety foreshadowed in the very first episode when the Starks find the direwolf pups. The pup given to Jon is completely white... much like the hair of Targaryens.

Ooooh, I like that idea! It has bothered me because Jon has black hair and in the first season, when Eddard reads the lineage descriptions they always included a hair color. I mentioned it somewhere and I was told that it was not always the case .... although, come to think of it, maybe their hair was white because they married family. Who knows?