Who would win in a UFC and boxing match?

I don't know who would win these fights, I ume the boxers would but you never know. What bothers me is Mayweather trash talking about any boxer could beat any UFC fighter. Bullsh*t. Like Dana White said, boxers are one trick ponies. If an mma fighter took a boxer down, their history. A boxer would have no take down defence against a trained mma fighter.