Board Thread:Naruto Discussions/@comment-3232093-20140617193601/@comment-1512913-20140617194400

Pointless to discuss, because everyone will tell you a different thing. I for one am positive that Sharingan doesn't evolve into Rinnegan, but that the original red tomoed Rinnegan evolved into purple Rinnegan and Sharingan. In case of Hagoromo, yes, since he had a purple Rinnegan, he must have had a Sharingan too, since they are two sides of the same coin. For Mangekyou Sharingan, that's a different matter. Depends on if he experienced traumatic enough experience/killed a loved one etc.