Queen Metroids belong to the second game Metroid II: Return of Samus, a number of Metroids that propagate the entire species and are also the last in the species' evolutionary line. They are less common than other Metroids due to them needing specific genes in order to mature into queens, as Samus remarks in Other M. In Metroid: Other M, the Galactic Federation researchers aboard Bottle Ship genetically manipulated genes from clones of the Metroid Hatchling, allowing at least one Metroid to grow to a Queen Metroid.