Musical styles stay pure very briefly.

The second a caveman heard another caveman hitting a log with a stick in a compelling way, he copied it and added his own style. And so it has gone throughout history.

So when rock and roll meets border music from Mexico, it shouldn't come as a big surprise. But still, the music of Brooklyn-based band "Pistolera" IS surprising...and refreshing.

The lead singer, guitarist and founder of Pistolera is Sandra Velasquez. She grew up in San Diego and says the rocking-border sound Pistolera has today was never calculated.