Even so, upon the ship's return to Spiral Town, they found they were too late. Everyone had succumbed to devastating cases of potassium deficiency; all had suffered severe mental retardation, and a great many were dead. The human gene pool on Destiny had been dangerously small from the beginning—more than half of the colonists had died from hibernation-related complications during the trip to the planet, and now more had died of potassium deficiency. The colony would now inbreed itself to extinction unless drastic measures were taken.