When you look into this and then look at all the unconnected places which have this symbol going back thousands of years there has to be a progenitor (if you can use that word for a symbol) for such a symbol to be independently create by so many unconnected cultures is not a coincidence, If we look at the biological history of the world:

Around 70-80,000 years ago a group of around 200 individuals left the horn of africa, crossed the red sea (when the sea level was far lower and much like a marsh) into the area of yemen and then spread throughout the middle east, europe, south east asia, siberia, australia and the americas. This is a biological fact and more and more archaeological evidence is turning up every year to support this.

It could be that this symbol has existed since the time of the early migrations, perhaps it was the symbol of the tribe which left africa.