Sorry sparkles it is not genetics.
I remember this argument when Borzov was close to breaking 10 37 years ago. I think it was steve williams who contradicted the genetic angle, instead pointing toward enviroment & technique. I am not positive it was steve commenting but the theory which i believe was along these lines,
one of the most important factors in the 100 is not popping up out of the blocks, you have to really fight the natural tendency to want to come too upright. in order to find your optimum angle for your speed you need to push your limits out of the blocks which means leaning so far forward as to fall on your face. It was pointed out that a common denominator of most great sprinters at that time, white or black was a more working class background. There is technique to running fast and alot of hard work involved as well. I live in Los Angeles, when i was running, in the more affluent areas the white guys were just as fast as the affluent blacks and only a few of the bused in blacks were fast. However in the economically depressed areas the guys were faster.
I had been a 200 man who was converted by a coach.
However i was pretty fast when i was working with a black coach from la southwest.
I submit that most of the best high school runners who are black are SURPRISE coached by former black sprinters. giving them a good 3 to 4 years head start on the white boys from other areas who can sprint(iowa, tim dwight, kevin little)
by the time they are in college the blacks kids have far too much of a head start plain & simple.
When i was running they use to say"you can't teach speed" which my black coach told me was bs. I ran a 4.5 40 between my soph & junior years, but because i was an athlete and my area was full of sprinters i gradually moved up to the half. In college i worked some with the sprinters and my times dropped by leaps & bounds, just with some decent sprint specific coaching. By then though i was succesful as a half miler/miler/cross country runner and actually had it in my mind thats what i was and i was putting in mileage and long intervals.
Years later when i ran across my coach at an all comers xc meet he asked what the hell i was doing.I was shocked he remembered me but even more shocked when he told me i was the best sprinter he ever had.
"but coach i was a miler" I figured he forgot"i was # 2 on varsity xc..."
"I know, you ran the mile & the half but you were always a natural sprinter"
Alot of other white guys who could be fast never get the chance to DEVELOP their ability because they are switched too quickly to longer events