Dax was a Trill symbiont born in 2018 and had been joined ten times up to 2375. Nine of the joinings were to official hosts with one a forced joining to Verad. (Star Trek: Deep Space Nine) Following the death of the host Jadzia Dax was transported back to Trill on the USS Destiny. During the trip Dax took a turn for the worse and had to be hurriedly joined with Ezri Tigan, who was the only Trill aboard the Destiny. (DS9: "Shadow and Symbols") In an alternate timeline Dax was joined several more times to descendants of Jadzia, the last being Yedrin. (DS9: "Children of Time")