Shared DNA in Music

I once had the realization that a riff from Metallica's "The Four Horseman" was the same as that from Tom Petty's "Last Dance With Mary Jane" except, as I learned several years after the realization, it is actually the riff from "Sweet Home Alabama" which was introduced in a session as a joke by the guitarist to make fun of the drummer for having narrow musical knowledge. He was correct in his assumption that the drummer wouldn't recognize it, and it was included in the final version of the song.

The story: https://youtube.com/shorts/nY6CPOtN47w?si=K_9EKvKGbgnuGKSg

The riffs: https://m.youtube.com/watch?v=2V6HbSkAD5g&pp=ygUgZm91ciBob3J...

Like a game of telephone but with guitar riffs

This is surprisingly common with Metallica for some reason. Could just be that they have so many tracks that statistically there's bound to be some overlaps.

Another example is "Welcome Home (Sanitarium)": https://www.youtube.com/watch?v=ZiIc0HuJ78Q

Whose intro sounds the same as "Rainbow Warrior" by Bleak House, released 5-6 years earlier: https://www.youtube.com/watch?v=zowid7KAmnM

Funny you mention "Mary Jane's Last Dance". The Red Hot Chili Peppers song "Dani California" overlaps with that (the chord progression is the same and rhythm style is pretty close too).

I've showed a few people this and I'm surprised that so many people don't notice that it's sweet home alabama. I am from Georgia though and that song used to be an anthem. lol