- Little is known about Tyler's life in the Prime universe, and bulk of this article deals with his life in the Pendragon timeline.
In January 2379, Tyler and Jeff were again on Vulcan, on a field trip as part of the Starfleet Academy Preparatory Program. They were visited by their father during the USS Pendragon's stop there on her shakedown cruise. Tyler and his brother encouraged Sinclair to return to Starfleet, allaying his fears about their well-being. (PDN: "True North")
After their time on Vulcan, Tyler and Jeff went to live on Deep Space 9, to be closer to their father during his mission in the Demilitarized Zone. On DS9, they spent a lot of time with their mother's foster brother, Miles O'Brien and his family. Tyler often babysat the O'Brien's youngest child, Kirayoshi.
Tyler's major at the Academy was xenoarchaeology, and he constantly resisted attempts (by Jeff and others) to get him to switch to a command track.
In 2381, Nebula Squadron went on field assignment to the Rigel system. Tyler spent most of his time investigating the history of the area and places of archaeological interest. On Rigel V, he befriended a young boy named Kaireth, and they shared an adventure in the mountains.
When the Squad visited Rigel II, Tyler became concerned when his brother Jeff began frequenting a cabaret and became involved with Alareh, a dancer there. Tyler cautioned his brother against getting in over his head, and was sorry to be proven right when they learned that Alareh had only been using Jeff.
Mere weeks before graduating, Tyler was shocked when Jeff left the Academy, until he found a letter his brother had left him, explaining that Jeff had learned Alarah had died, after bearing their son.
Tyler graduated from the Academy in May 2384. (PDN: "Sometimes It Comes In the Clouds")
At least twice, Timothy Sinclair was given visions of his sons' possible futures. In one, he saw Tyler becoming Captain of the USS Dawn Treader in the year 2398. In another, he saw Tyler and the Dawn Treader defending the Colonial Alliance from an unknown enemy. According to Darrum, this future was jeopardized after Sinclair saved his crew in late 2384. (Star Trek: Pendragon: "An Evening In Gethsemane", "The Light of Distant Shores")
In another timeline, one branch of the prime universe, Tyler was still captain of the ShiKahr-class Dawn Treader in 2402, when his nephew Tristan Sinclair graduated from Starfleet Academy and assigned to his ship as a tactical officer. (Star Trek: Sons of Liberty: "For I Dipt Into the Future...")
Being an identical twin, Tyler was of course very close to his brother, Jeff. As children, they did everything together, and even shared a strong telepathic link, learning to communicate with each other in that manner by the time they reached age five. Though they had some friends their own age, especially Jeff, both boys were like their father in that they preferred their own company, or that of grownups, over other children. Tyler always looked up to Jeff as the stronger of the two, both physically and telepathically, and they leaned on each other heavily after their mother's death. Tyler and Jeff remained close all throughout their formative years and well into their time at Starfleet Academy. Tyler was saddened when Jeff gradually withdrew from their mental link after the incident on Rigel II, and they slowly drifted apart until Jeff left the Academy.
Growing up on Earth, Tyler came to regard his father's circle of friends as a kind of family. Roger and Elaine Bartholomew were his godparents, and Steve Tecklenberg, John Seilback, Mark Montgomery, and especially Ben and Jason Bartholomew were all his "uncles." Likewise, his mother's foster family were also part of his "extended family," especially his "Grandma Fionnula," and "Uncle Miles."
Hobbies and InterestsEdit
Tyler was always interested in history, something he learned from both his parents. He developed an interest in archaeology during his travels with his father, and followed in Sinclair's footsteps as a "Preserver chaser."