Can you wonder at it?
A Celtic melody sounds this way, a French or German melody that way. Same could be said for Greece, Persia, India and really as far and deep as you care to look. Basically you have a group and the tendency is, like language to diverge and develop an idiosyncratic identity that subconsciously mirrors it. On top of that is the cross-cultural exchange of ideas and other developments which occur only under the grand forces of time.
But where does that particular affinity for favouring that particular combination of notes come from? I cannot narrow it down to a logical reason other than that it is somewhat hard-wired into the soul, something even the most extremely individualistic composer is bound by.
Observing this genealogy in metal can be even more interesting than that of strictly traditional music. Examples of some of the more obvious strains that strike me are:
Incantation - Profanatica -> Demoncy
Blasphemy -> Impaled Nazarene - Beherit <- Bathory
Bathory -> (+ Hellhammer) ->The entire pantheon of early Norwegian black metal.
For black metal I think this was best exemplified in Darkthroneís Transylvanian Hunger
or the works of Ildjarn which is essentially a distillation of that melodic form. The sheer recombinance of riffs over the Ildjarn discography speaks volumes for the subconscious and this gravitational pull within the soul.
As an aside I occasionally experienced some odd phenomena myself while out walking in woods and meadows. A melody passes through my head, seemingly unique in all the world, then at a later date I have heard it or some similar variant being used in someone elseís music. You could say they beat me to it, unless they actually did it before I had thought of it, though I honestly canít recall having heard it before, at least not in this life
Can you wonder at the DNA of a soul?