British researchers of the University of Warwick and the University of Sheffield have come in aid to answer this question and settle heated cocktail party arguments around the globe. The chicken came first, or rather a key protein needed to form the shell of the egg. The protein, called ovocledidin-17, was known to be involved in binding calcite molecules that formed the shells, but the mechanism behind this was unclear until now.

The protein acts as a molecular machine, binding to nanoparticles of calcite and guiding them to begin self-assembly of the shell. This gives tremendous insight for developing methods of nano-scale self-assembly based on natural processes.