More on the apparent genocide 4500-5000 years ago that happened when people from the steppes near the Caspian Sea moved into the Iberian Peninsula. Though 60% of the region’s DNA remained the same, the Y chromosomes were almost totally replaced. This indicates that men from the steppes appropriated all the women of the area, or they killed most of the male inhabitants.
What allowed them to do this? They apparently had three things that the local population had less or none of: horses, bronze weapons, and wheeled carts.