Primordial Pac-Man: Oil droplet hints at life's origin: Could that be because biologists have been looking at the wrong part of the experiment? A fresh look at the tarry residue left behind in a Miller-Urey-style experiment has revealed something remarkable: when injected into a simple oil droplet, the gunk endows it with spookily lifelike behaviour - although crucially it cannot yet reproduce. Like Pac-Man, an oil droplet doped with tarry junk can sense and respond to its neighbours and move towards "food" sources.
Although the Miller-Urey set-up is best known for producing amino acids, its primary product is a complex hydrogen cyanide polymer that looks like black tar and has mostly been ignored. "For the most part, people filtered it off and threw it down the drain," says Bob Minard of Pennsylvania State University in University Park.