Lifeisharsh20 has been a trekkie all his life. His favorite series was The Next Generation. He has also watched The Original Series, Deep Space Nine, and some episodes of Voyager. He isn't too knowledgeable about Enterprise since when they were making new episodes, he didn't get UPN, or The Animated Series since that was before his time and was not syndicated on any channel he remembered getting and is too poor to buy the DVDs. He is a recently joined Memory Alpha and has made some minor edits. When he has time (read when he gets done with Grad School where he is currently studying for his MA in Mathematics), he plans on watching the many episodes of the Star Trek series he has missed to see if he can improve any articles besides minor grammatical details. He is still learning how to link and italicize in Memory Alpha, so please bear with him.
TNG Trill vs. DS9 Trill Differences Edit
For years people wondered why Klingons from the movies and subsequent series had ridged foreheads while those in TOS didn't. The real-world explanation is that TOS didn't have the budget for the ridged foreheads, while the movies and the subsequent series did. Stark Trek: Enterprise finally gave an explanation for this, but what about the differences between the TNG and DS9 Trills?
Startrek.com explains that there are apparently two races of Trill used to house the symbionts: the ridged forehead ones and the spotted ones. This seems reasonable seeing as how Earth itself has various races: Native Americans, Caucasians, Africans, Asians, etc. Why would Trill be any different?
Now off to the unexplained things:
The symbionts also looked different. Perhaps there are two races of symbionts as well, and perhaps the TNG symbiont race works better with the TNG ridged Trill and the DS9 one worked better with the DS9 spotted Trill.
Odan was only referred to as Odan, while subsequent joined Trill were referred to by both the host name and the symbiont name. Perhaps the ridged race preferred to go by the symbiont's name only. Or perhaps Odan's hosts individually chose to be referred to as just Odan. It's not uncommon for humans to be referred to by their last names by choice of the individual.
Odan refused to use to the transporter because it could harm the symbiont, but Jadzia Dax had no problems. Perhaps transporter technology improved to the point where joined Trill could use transporters with no harm to the symbiont, or perhaps Odan was lying because of a fear of transporters.
Odan was also willing to continue his/her/its relationship with Dr. Crusher despite the Trill taboo about renewing relationships. Perhaps this taboo only applies to fellow Trill and they create an exception regarding interspecies relations. We see the Dax hosts renew their relationships with Benjamin Sisko, Worf, and Doctor Bashir.
Odan's pulsating stomach vs. Dax's non-pulsating stomach. Perhaps this is simply how the ridged-Trill reacted when joined, or perhaps Trill technology improved to such a point that the pulsating stomach was eliminated, or maybe we just didn't see it. The Dax hosts weren't on-screen 100% of the time.
Riker able to host Odan temporarily and survive vs. joined Trill hosts dying if separted. This answer is deceptively simple. While Human biology is similar enough to humanoid Trill biology to be a host to a Trill symbiont, it is different enough to allow the host to be separated without killing him. In fact, Riker almost died playing host to Odan.
Odan's dominance vs. the blend of personality of the Dax hosts and symbionts. This is harder to explain. Maybe it just appeared that the Odan symbiont was more dominant than the host given that the host was probably tapping into the symbiont's memories of previous hosts' negotiation skills. After all, DS9 has established the symbiont does retain previous hosts' memories.
Now what about not knowing that much about the Trill in "The Host" but Dax being involved with the Federation prior to this. Also hard to explain. It could be that the Trill were secretive about their joined status until the events in TNG forced them to reveal it, and possibly only a few select Trill were in contact with the Federation prior, not giving all the information about their culture until TNG and DS9.
If you want to, you may discuss this on my user: talk page, I'd like to know what other people think.