What is known is that the entire Dominion is composed of only one species, the Tareqi. They do not tolerate outsiders nor do they offer citizenships to other species. It is unknown if they expanded to their present size through conquest of other species or through colonization of uninhabited planets. Though the exact number is unknown, contact with Tareqi diplomats seem to indicate that there are at least 100 billion Tareqi, though how much more is unknown.