Board Thread:Boruto Discussions/@comment-33255203-20171004210031/@comment-6769189-20171027174550

Everyone who has talked about advancing eyes to Rinnegan/Tenseigan never said they needed to be transplanted, only that the eyes require certain chakra to be added to them. On the EMS was stated to require a transplant and the whole Sharingan dojutsu line is seperate from the Rinnegan line.

Only someone not of the bloodline with the power of the eye

One only needs certain chakra applied to certain eyes to achieve Rinnegan/Tenseigan. Chapter 671 around 53 minutes or so into the Last confirms this