Gene Nation began as a faction of the underground mutant colony called the Morlocks. At one point, Mikhail Rasputin, when fleeing the X-Men, found refuge in the Morlocks tunnels. He took no time at all, however, to set himself up as their leader, and when the X-Men came looking for Rasputin, he used his powers to flood the tunnels, and all of the Morlocks were believed to have died. Secretly, he teleported himself and a select group of the Morlocks away to another dimension.
In this new dimension, dubbed “the Hill,” these mutants developed their own culture, especially since time passed more quickly in this dimension and a new generation of Morlocks were born and raised. Life on the Hill was full of constant battle, as Mikhail’s fortress stood atop it, and only the strongest, most capable mutants could fight their way to the top and be accepted in his Gene Nation. Its people grew hardened, callous, and full of malice. One such mutant, Marrow, grew from a scared little girl into an embittered young woman.
First calling themselves Gene Nation, the mutants began making forays to Earth and began a series of terrorist attacks on the human population of New York, starting with a mass murder at a New York club. The X-Men investigated, believing the attacks to come from the Morlocks. They discovered a community of Morlocks still existed, but the Morlocks explained the militant Gene Nation was determined to kill one human for every mutant that died in the Mutant Massacre years ago. On the anniversary of the Massacre, the X-Men confronted Gene Nation. The two teams’ leaders, Storm and Marrow, engaged in a one-on-one battle. Marrow threatened to blow up New York's subway system, along with a hundred commuters, as payback for the mutants killed. During their battle, Storm was forced to pull out Marrow's heart to stop the bomb that was attached to it. Believing that she was dead, Storm left her in the tunnels; however, Marrow survived, having two functioning hearts as a part of her mutant physiology.
Later, during a memorial for the Morlocks, Storm discovered a portal to the Hill, and she learned the truth about the origins of Gene Nation. She fought her way to confront Mikhail, forcing him to return all Morlocks back to Earth. Instead of repopulating the Morlock tunnels, Storm helped them settle into an African village, although Mikhail escaped to the Hill once more.
It was later revealed that the Morlocks were largely used by the Dark Beast for secret genetic experiments. At some point, he gathered various members of Gene Nation for his own version of the team. Hoping for new experimental subjects, he targeted the young mutants of Generation X, and his Gene Nation succeeded in capturing them and returning them to the Morlock tunnels. Generation X’s mentors, along with X-Man, rescued them and Gene Nation escaped.
The most recent version of Gene Nation was created by Marrow after her experiences with the Weapon X program. At first a willing agent of the program, she began to suspect that she was not told everything about the program and its ultimate motives. She and agent Brent Jackson helped other agents form a group to stage a coup, soon joining the mutant team Underground, led by the Cable who hoped to take down the Weapon X program. The Underground was able to infiltrate the Weapon X complex, ousting the Director and nearly crippling the program. However, before the final defeat, Agent Jackson betrayed the Underground. He captured the Underground members, but Marrow returned to rescue the members of the Underground and return with them to their base. However, this proved to be a front, as Marrow tricked Cable into believing that the Underground was successful, thereby gaining information about the various Underground cells around the country. She then proceeded to convert the Underground cells into a new version of Gene Nation, hoping to once again create a mutant terrorist army.
Ultimately, however, Marrow and Gene Nation were systematically hunted down by Weapon X's operative Agent Zero, who killed every member of Gene Nation but left Marrow alive to humiliate her.