How did the gene for music and dance survive? What kind of benefit did it provide early man, according to evolution? Or is this a late mutation that happened after man devolped an appreciation for the arts?

On the surface, it doesn't appear that the ability to make music or dance has any benefit in survival like the ability to hunt, grow food or fight does. According to survivial of the fitest, those with survival skills prosper and reproduce while those without such skills die and the gene pool diminishes.

Life is movement. Life has a rhythm of its own.

The heart has a beat.