A wealthy group of White Supremacists have finally gathered enough funds to colonise Mars. Approximately 100 of them, carefully selected for ‘purity’, make the journey to the red planet, their utopia.
Free of the inferior and troublesome races, they can finally live a safe and prosperous life.
Skip forward 50 years, the colony has been thriving; a population of 1000 pure, terraforming underway, and a bustling economy. Clearly they have been successful in their mission to create a new world for themselves. While remaining hostile to outsiders.
However, a new deadly virus has quickly spread through the entire colony. It’s highly contagious, has a long incubation period, and is lethal to all who contract it. Due to the lack of diversity in the MCH (major histocompatibility complex) genes, noone’s immune system can adapt to fight the virus.
They all die.