Board Thread:Naruto Discussions/@comment-3232093-20140617193601/@comment-2172835-20140821104548

Geez this is seriously an intense topic. My thoughts were only a suggestion. Looking at some of the comments it's plausible that a number of theories are correct.

To clarify I have stated that the Sharingan and the Rinnegan are intrinsically linked, which may be evolution of the Sharingan into the Rinnegan but I haven't stated that. If we were to take what Orochimaru/Kabuto's theory states as fact that would say that evolution is present. My theory is distinct as it implies that the Sharingan and Rinnegan maybe present simultaneously, creating the unique eyes used by Shinju/Sasuke. Further the Hagoromo's eyes without the distinctive tomoe could be a result of two reasons in my opinion:

1) He has not got or ever had the Sharingan

2) His Sharingan is not active when we have seen his Rinnegan/eyes.

Personally I'm leaning towards the latter reasoning, simply because of the evolutionary comment made by Kabuto. If he was not born with the Rinnegan as a few have suggested then a trigger must be present for him to receive this. Further to this his son is said to possess his eyes, to which he is shown with the Sharingan, it wouldn't be absurd to assume that Hagoromo originally and still possess the Sharingan. Further explanation to my theory can be seen from my original comment above.

Ultimately I'm not saying this theory is true but from what I've seen(as stated my initial comments in this thread) this is a likely explanation for myself.