Mark Gunther was a human male in the 24th century. He was the son of Abram Gunther, a psychologist and former Starfleet officer. He followed his father into the service, rising to the rank of lieutenant, with his first starship post as a tactical officer on the USS Constitution. Unfortunately he died on February 10, 2381, along with rest of the personnel of the Constitution and the allied fleet defending Deneva during the Borg Invasion of 2381. (DS9 novel: Force and Motion)