The best source of what "rekrunner" points out are posts written by me. Among the worst are posts written by "Coevett".
What I will point out in this 3-year old thread which was bumped:
This whole thread is misguided, by attempting to create a false dichotomy between genetics and doping, and ignoring other factors, like environmental.
"Borderline" is a little confused about marathon history, as when EPO hit the scene, the marathon record didn't move until 1998. It moved a little further with Paul Tergat by 2005 (with a time still unmatched today by any non-African), and a little further again with Haile Gebrselassie by 2008, who showed us what he could still do in the marathon, at the end of a long 17-year career at the top. It was only when younger athletes started skipping the track and going to the marathon fresh in their careers, that this record started dropping significantly, followed again by the introduction of carbon-fiber plated, thickly-soled shoes.
I never looked at Antarctica, nor athletes from outer-Mongolia specifically. I looked at all performances worldwide spanning more than three decades, including the entirety of the EPO-era from a fairly complete dataset. Between 1990 and 2018, I found 9 non-Africans faster than Steve Jones and Carlos Lopes of 2:07:12/13. I also found only 6 North Africans faster, and 3 South Africans faster. If these are clean performances, that means the best EPO performances among these selected groups worldwide over nearly three decades are slower. But presumably, these performances are the upper limit of what EPO could do for most of the world, for three decades, outside of East Africa. The best of the non-Africans then was about 1 minute faster (Brazilian Ronald De Costa from 1998), and North Africans were about 30-40 seconds faster by 2009. Since my look at performances in 2018, the Japanese have pushed this best another 30+ seconds, with Kengo Suzuki running 2:04:56, about 36 years after Jones/Lopes, and about 2 minutes faster, and still 1 second slower than Paul Tergat.
One possibility is that, despite the strong belief as a powerful endurance drug, EPO and blood doping simply wasn't used, with a few rare exceptions, for three decades, across 5-continents, and North and South Africa.
But if you asked me, athletes like Ryan Hall, Sondre Moen, and the Robertson Twins indicate that clean non-East Africans can still do much better than they have, if they can commit to living and training at altitude, not just for 3-4 weeks, but for extended periods lasting months and years.