In the research of Saltin and Terrados, with children from Scandinavia and Kenya, there is an identity of values when are very young, and a growing difference when are older.
Probably this fact is due to the difference in type of life between the two groups investigated.
I wrote before that Training is not only OFFICIAL TRAINING for a discipline, but is every human activity that can modify your physiology.
If you take two twin brothers, one seated 8 hours per day because employer in an office, the other working 8 hours in the country, and you train them with same workouts, their output during a race shall be very different, because really THEIR TRAINING IS NOT THE SAME, having the countryman a physical activity that must be added to the official training.
EFFECTIVELY, HE IS MORE TRAINED.
So, may be that the difference between white caucasian people and african people from highlands is not genetic (if not in little percentage), but mostly phenotypical (due to different activity).
For the same reason, old Italians were more talented that current Italians, and also old Kenyans were more talented than current Kenyans.
Kip Keino told me that never he trained more than 2 times per week, and his training was only on track. He could not run in the roads or in the forrest, because at that time it was not dignified running in shorts publicly !
Now, the main reason of african supremacy is that running is a profession, already good also for normal athletes. If you think that a normal kenyan salary is about 1.500 dollars per year, you understand how a not very strong athlete is able, in one season, to earn more than in 10 years of normal job at home.
This fact is a big motivation for a lot of kenyans, so today the common mentality changed, and runners are considered lucky people, not crazy men.
I suggest not to consider the differences between kenyans and white people, but between OLD WHITE PEOPLE and NEW WHITE PEOPLE. If genetically we are the same of 30 years ago, why our talent is now so much lower ? Because we have no more preparation enough thru our normal life, that excludes physical activity, expecially in the field of endurance.
So, it's true that now Britains have yet Jon Brown, Keska, Pavey and Tullett ; but once Coe, Ovett, Cram, and before Bannister, Chataway, Pirie and many other WERE THE BESTS, not among top ten.
Athletics can be measured, and now Europe is very less competitive than 20 years ago. So, our decline has the effect to light up the african results, that often are normal, and not so good.