Keiko O'Brien worked as a botanist aboard the Star Ship U.S.S. Enterprise D. She eventually married Miles O'Brien. The couple later had a daughter named Molly O'Brien and the family eventually relocated to Deep Space Nine when Miles was transferred.
Keiko was created the the television show Star Trek: The Next Generation.
When Keiko first came aboard Deep Space Nine there was no place for a botanist. She advocated and became the school teacher on the station for a time until there were no more children on board to warrant a school. She did have a huge impact on her students however and was a catalyst for Nog joining Star Fleet after getting an education in her school.
After her school was closed Keiko went on service vessels that needed botanist. This meant she would be gone for long periods of time while Miles was on the station. She would take Molly with her and this left Miles alone on the station. Later, Miles and Keiko would have another child but due to an accident Keiko was no longer able to carry the fetus to full tern and it was Kira Nerys who ended up carrying the child till his birth. After the Dominion war the whole family moved back to Earth.