Pascal Boyer gives an analogy to explain why it is we can’t find the predisposition to acquire religious beliefs in our genes. He compares our ‘capacity’ to have religious beliefs to other capacities, like being able to catch a cold or to remember different melodies.
We can catch colds because we have respiratory organs and these provide a hospitable site for all sorts of pathogens, including those of the common cold. We can remember tunes because a part of our brain can easily store a series of sounds with their relative pitch and duration. There are no common colds in our genes and no melodies either. ... Normal genes in a normal milieu will give you a pair of lungs and an organized auditory cortex, and with these the dispositions to acquire both colds and tunes. Obviously, if we were all brought up in a sterile and nonmusical environment, we would catch neither.
Of course the analogy itself proves nothing - the proof, as far as it goes, is in the rest of Boyer's book. Also, to me the ‘common cold’ analogy seems to me somewhat different from the ‘melody’ analogy. Clearly when you are never exposed to the virus that causes the common cold, you will never be infected. It is however less plausible (especially when talking about more than one generation) that humans will not rediscover melodies at some point - but subsequently those melodies will be entirely different melodies.
Pascal Boyer (2001) Religion explained : the evolutionary origins of religious thought. Basic Books: New York.