Heavyweight champion  Tom Aspinall will put the title on the line for the first time as undisputed titleholder against top contender  Ciryl Gane in the UFC 321 main event.  Aspinall, the former interim champion, defended the interim title at UFC 304 finishing  Curtis Blaydes in 60 seconds. He was elevated to the undisputed champion on June 21 after former titleholder  Jon Jones announced  his retirement .