Talent isn't a myth, natural talent is a myth. The idea that someone was born with a natural aptitude to do something bizarrely specific like playing a board game with very unique rules (chess) or swing a metal thing to get a tiny ball in a tiny hole is a myth. Talent is purely the product of practicing something enough that your body/mind becomes good at it.
Wait, so you are saying we mapped a golf gene? And a basketball gene? And a piano-playing gene? You think it says stuff like that in the genetic map? What about biology am I ignoring when I say that nowhere in our genome are their instructions to play golf?
Now you are getting silly. No there is no golf gene. But there is natural talent at physical elements whose presence enables someone to be very good at golf in a fairly short time and whose absence imposes a limit on how good someone can get at golf no matter hos much they practice.
As to the necessity of practice and training. Did that happen in utero for Mozart, who started writing world-class music at age 5?