Where did the ninja clans other then Senju and Uchiha originate from? In the anime, it is shown that the Senju and Uchiha clans originated from the Sage of Six Paths who is the God of Shinobi. Where did the other clans like Sarutobi, Nara, Inuzuka, clans from other countries originate from?
Recall that the Sage of the Six Paths discovered the existence of chakra and used it to create jutsu. The direct descendants of him became Senju and Uchiha, where their powers were split between body and eye.

Other ninja clans were not descendents, however they were able to learn how to use chakra as well in different forms of jutsus. Of course there are some clans, like the Hyuuga where the series notions the possibility of them deriving from the Uchiha.

Clans like Sarutobi, Nara, and Inuzuka clans are not related to the Sage of Six Paths though. On the other hand, Uzumaki is blood related to Senju.