Original: The film is loosely based on two X-Men comic book story arcs : writer Chris Claremont 's and artist John Byrne 's '' The Dark Phoenix Saga '' in The Uncanny X-Men and writer Joss Whedon 's and artist John Cassaday 's six-issue '' Gifted '' arc in Astonishing X-Men .
Simplified: The movie is partially based on two X-Men comic book stories : writer Chris Claremonts and artist John Byrnes '' Dark Phoenix Saga '' in The Uncanny X-Men (/O1980/O) and writer Joss Whedons and artist John Cassadays six-issue '' Gifted '' story in Astonishing X-Men (/O2004/O) .