They've got the right idea, but possibly a too-Eurocentric execution. So to speak.

I had to look up to make sure it wasn't an urban legend, but about .5% of the men currently alive in the world have DNA from Genghis Khan. Maybe the muties should have gone after him...From 1988, Strontium Dog #18, "The Ragnarok Job, part 4 of 5" Written by Alan Grant, art by Carlos Ezquerra. Cover by Jackson Guice. 

Max Bubba and his mutie gang have escaped from the future, to the year 793 AD, but they aren't just hiding out there. Bubba is going to wreck the timeline but good, by killing a village-full of Vikings. Although they can't understand him, he still explains to them (to note the "historic moment") that by the 22nd century, their DNA had spread to just about everybody. Killing them would prevent their descendants from ever being born, and history would crumple like a house of cards. Bubba mentions a couple times, he has nothing against the Vikings, but the "norms" in the future have it coming for their persecution of mutants. Of course, he also thinks the muties would then inherit the earth, but I kind of feel like the mutants probably also had a lot of that DNA, before it was mutated? Bubba's plan would change the future so much as to be unrecognizable and unpredictable, but, well, omelets and eggs, I guess.

Time distortions were already appearing, like the volcano Bubba planned to march the Vikings into, and a Vietnam war-era helicopter and soldiers that arrive in time to help Strontium Dog Johnny Alpha and his crew get to the fight in the nick of time. (Grant has a dark throwaway line there, when the commanding officer agrees to help Johnny but worries "what if the target turns out to be innocent civilians?" A soldier immediately pipes in, "when's that ever stopped us, cap?") The distortions were also felt in 2170, with buildings collapsing and people disappearing: had Johnny Alpha failed the future?

Bubba's "Black Viking" locals are no match for the U.S. army, who in turn are largely shot up by the muties. During the firefight, Bubba tries to persuade Johnny into joining up: it's not like he owed the norms anything, really. Johnny may almost be tempted, but had no desire to be "murdering trash" like Bubba. But Bubba has the drop on him as the chapter ends...!

It took a little searching, but these were originally from 2000 AD #460 and thereabouts. This was also a storyline within a longer storyline, with the origin of Johnny's partner, Wulf; who gets sent to the future there. And the shoulder on my old Strontium Dog action figure broke; I'd love to see new 2000 AD figures again someday. I'd prefer mass-market to super-fancy, but could be talked into it! 

Also this issue: another segment of "Bad City Blue," a sci-fi action number with what appeared to be a space habitat with "class A" elites and just about everyone else is "slumscum," with operatives like Blue enforcing the peace. But the class A's may have disappeared...This was the first chapter of this one I remember reading, and it seems pretty meat-and-potatoes, but not bad.