On the Naruto universe Earth, Otsutsuki Hagoromo gained the Rinnegan somehow.
Gaining his power, can unlock the Rinnegan, as we saw with Madara, who fused Ashura's chakra with his own chakra (Indra) into Hagaromo's chakra.
You dont need to be Senju + Uchiha. You need Hagoromo's chakra or Ashura + Indra=Hagoromo's chakra.
So it happens, Ashura was reincarnated in someone from the Senju lineage (Naruto) and Indra in someone from the Uchiha lineage (Sasuke). However I bet if Indra choose a Hyuuga for reincarnation, that he could still get Rinnegan, if he got hold of Ashura's chakra to fuse with his (As Madara/Indra did).
So in essence, Rinnegan is no higher evolution from Sharingan, as Kabuto and Oro theorized.
In Boruto the movie, we see Momoshiki. He is an Otsutsuki, with the Rinnegan.
Before he absorbs Kinshiki, Momoshiki has a red Rinnegan.
After he absorbs Kinshiki this red Rinnegan, becomes the white purplish Rinnegan.
So Rinnegan might just be a possible dojutsu that some Otsutsuki can have, besides their Byakugan.
Gaining his power, can unlock the Rinnegan, as we saw with Madara, who fused Ashura's chakra with his own chakra (Indra) into Hagaromo's chakra.
You dont need to be Senju + Uchiha. You need Hagoromo's chakra or Ashura + Indra=Hagoromo's chakra.
So it happens, Ashura was reincarnated in someone from the Senju lineage (Naruto) and Indra in someone from the Uchiha lineage (Sasuke). However I bet if Indra choose a Hyuuga for reincarnation, that he could still get Rinnegan, if he got hold of Ashura's chakra to fuse with his (As Madara/Indra did).
So in essence, Rinnegan is no higher evolution from Sharingan, as Kabuto and Oro theorized.
In Boruto the movie, we see Momoshiki. He is an Otsutsuki, with the Rinnegan.
Before he absorbs Kinshiki, Momoshiki has a red Rinnegan.
After he absorbs Kinshiki this red Rinnegan, becomes the white purplish Rinnegan.
So Rinnegan might just be a possible dojutsu that some Otsutsuki can have, besides their Byakugan.