Two of the fundamental mysteries of physics now has a new theory to explain them both. The "X-Particle" is a hypothetical particle that is thought to decay into matter and neutrons. Created by the big bang, the X-particle had a companion particle the Anti-X-particle, which decayed into anti-matter and neutrons. It is these particles which have decayed into the matter which we can see and the dark matter we cannot. This theory has proposed new concepts that could explain why dark matter is so prevalent in the universe.
X Particle Explains Dark Matter and Antimatter at the Same Time | Wired Science | Wired.com: "out dark matter is that it is mysterious stuff that makes up a quarter of the energy density of the unive"