HRE makes some very good points. i don't know why everyone is bashing his posts. i think people are misunderstanding him. he's not saying that genes don't play a role. he's saying that there are other factors to why someone during say one particular season or stretch of training is better than another person despite training less.
lets say two kids are training for the 5k and one kid runs slower despite training more. well maybe he's more naturally attuned to the marathon and he will excel far more at that than the currently faster kid could ever do at any event.
or maybe their coach focuses on interval training but not tempo runs and the currently faster kid responds better to intervals while the slower kid plateau's quickly with just intervals and isn't getting the needed strength work he requires to excel.
maybe the slower kid is maturing slower so he won't hit his prime until a few years after the currently faster kid.
maybe the slower kid is overtraining and running too much, but he always does that cuz he thinks he needs that to succeed.
maybe the slower kid isn't sleeping enough or eating enough. maybe he's just naturally weak and with a couple years of strength training his running would improve a vast amount.
HRE is saying that yeah genetics play a role but its not always so clearcut that you can say that if one person is doing better than another off similar or even less training then that faster person must have superior genetics.
sometimes it is pretty clear, but not always. a guy i ran with in college could run about a 2:05 800 and 4:45 mile after maybe going on a couple runs beforehand after not running for a few months. he obviously has incredible talent, much more than say someone who can't break 4:40 until they're at like 40 mpw and have been doing workouts for a month. but even then, maybe that naturally talented guy doesn't believe in doing mileage and he never runs faster than 4:20 (yes, that is what actually happened). while the much less naturally talented guy might in 5 years time with consistent hard training and consistently smarter training run a 29:00 10k (4:40 mile pace). in college you might say that guy doesn't have much natural talent, after a 29:00 10k you'd say he has plenty of natural talent.
natural talent does exist. but it is often times hard to quantify because there are so many factors at play. i think that someone who early on isn't thought of as super genetically gifted can make the olympics because people only base their idea of someone's genes on what they have done so far. maybe you train really hard and run a 14:20 5k in college. good job you have good running genes, but nobody ever expects you to make the olympics. then after college you start training on your own in a new place and you find you are suddenly improving a lot more with different training and a different environment. Four years later you are at 13:20. good job, now you have far better genes than you did in college and now might go the olympics. Now that isn't a real life example but that sorta thing does happen and it does show that when people talk about someone's genes they are really just complete guesses.