Actually, some of your comments on this subject are a bit more "left field" than the possibility of teaching a chimpanzee to become a grandmaster.  If you think that we are so much the same genetically, what do you believe about human ancestors 100,000 years ago?  2 million years ago?  My point is that with mitochondrial DNA sequencing showing how much our genetics has changed over that period of time, you can figure that the mutations that tend to occur allow for a pretty wide variation in physical and mental characteristics.  And, lo and behold!  Mitochondrial DNA sequencing also shows these to be present, confirming what should be painfully obvious to those who cannot see the forest for all of the trees.  Motivation, of course, counts for much.  In general, unless someone is suffering from a physical deformity, whether it be malformed physical parts, genetic predisposition toward certain things like anemia, etc., then if that person works hard enough, he can become stronger, faster, or whatever compared with the vast majority of people in the world.  However, that doesn't mean that the person can become an Olympian--that vast majority of people, even when working hard enough, simply cannot do this because the level of competition at that level is high enough that certain physical traits that are not so common to most people give the extra possibilities, both in terms of training/recovery and in terms of the competition itself.  In running, people with long legs and high torsos in relation to the rest of their body have a definite advantage, and this is something that has been known to physiologists for a very long time--it's actually really basic and really obvious.  I have neither of these things.  I can often do well enough, and I win ~50% of the local long-distance races in which I compete.  However, when I compete in races against elite runners, things are altogether different--they have a very different physiology that allows them to get much more out of their training than I get: they can train harder and recover more quickly, and even if they don't, they can still more effortlessly run in the races.  This is just one example--it goes like this in other sports, too.

Meanwhile, it should be very obvious that someone with an IQ below 85 is not going to become a super grandmaster.  This may sound like a random number, but it accounts for 16% of the people in the world.  For that matter, I would guess that nobody rated over 2500 has an IQ of below 100, while meanwhile, people with IQs below 100 account for 50% of the world's population.  The same goes for theoretical physicists.  This should not be difficult to understand.