By the early 21st Century it became obvious to many people that Homo sapiens had phase separated into two subspecies: Homo individualis and Homo collectivus. The former was the end result of classical Darwinian competition for resources and progeny; the latter came about following the handoff of evolution from genes to memes. H. ind. was selfish, irresponsible and uncaring; H. coll. was generous, responsible and caring. Once the phase separation was more or less complete, H. ind. began to exhibit more extreme behavioral traits such as narcissism and a cynical disregard for (or even a total lack of awareness of) social norms and contracts. Meanwhile, H. coll. became obsessed with the perfection of society and haunted by their own failure to live up to expectations.
Into this world came a H. coll. named Anthony Ahol, who chose a career as a geneticist and formed the hypothesis that the difference between the two subspecies could have a detectable genetic signature. Anthony obtained DNA samples from thousands of persons who displayed all the characteristics of H. ind., even going so far as to disinter famous individuals from the recent past. His research was finally successful: the complex of genes common to most members of H. ind. was dubbed the Ahol factor, after its discoverer. Naturally the name was consistently mispronounced by most H. ind. folks, usually with a measure of pride.
Within a few years, Anthony began to wonder if there might be a "cure" for the Ahol factor. He experimented with various viruses that might attack the specific genes causing H. ind. characteristics, and eventually found a very effective strain. Unfortunately, although the virus simply deleted the Ahol factor in vitro, leaving the cell cultures otherwise healthy, when he accidentally dropped a contained of the virus and it escaped into the world, he found that it was not so benign to the complete organism: within a year, every member of H. ind. was dead. There followed a period of peace and prosperity unlike any the world had ever seen. Through cooperative effort and self-sacrifice, H. coll. managed to eliminate poverty, hunger and exploitation, cease production of greenhouse gases, replace fossil fuel-burning power plants, individual automobiles and roads with solar and wind power, self-driving free electric taxis and buses and quiet, high-speed light rail transit systems. All health care and education was free. No one tried to accumulate excessive wealth, everyone behaved responsibly and helped each other achieve their best possible selves.
Unfortunately, the previously noted negative correlation between standard of living (including education) and number of progeny continued until essentially no children were being born; within a century H. coll. was also extinct.