Bajorans don't originate with humans, but they likely share a common history.
See this answer to this question:
Is the humanoid appearance of most alien species in the Star Trek universe ever canonically addressed?
about the possible common origin with humans. It's never explicitly stated that this applies to Bajorans, but it does for Cardassians (who are close neighbors) since they appear in the episode "The Chase", and this is the given in-universe explanation for the large number of humanoid aliens in the Alpha and Beta Quadrants.
Here's the answer given in the link:
In Star Trek: The Next Generation's "The Chase", the Federation, Klingons, Cardassians, and Romulans are all on what amounts to a treasure hunt:
Representatives of all three races are together when all the pieces are put together and it turns out to be a program that takes over a tricorder and projects an image of an ancient alien who tells them that they found the galaxy empty, other than themselves, so they spread seeds of DNA throughout so there would be other races and that the existing races would be descendants of that seeding.
I would also add that Bajor has a history dating way before any high civilization on Earth (25,000 years), and there has never been a fallen space-faring human civilization posited this early from Earth in the Star Trek universe.
However, there are also the Preservers, possibly or possibly not the same race as in "The Chase", that could have transplanted humans to Bajor early on, but there has never been a suggestion in-universe that this occurred or any suggestion that Bajorans didn't evolve on Bajor.