Gamma 7 sector was a region of space. This sector contained the Federation planet Gagarin IV. In 2365, the USS Lantree was assigned to the Gamma 7 sector, when her entire crew fell victim to a mysterious disease. (TNG: "Unnatural Selection" ) In the episode's script , the Lantree was assigned to Gamma seven seven. For the filmed episode, the second "seven" was changed to "sector".