This is the question which intrigued mankind from the earliest of times. The answer is tricky because according to our experience a chicken always comes from an egg and an egg always comes from a chicken. It is like saying “Which came first, X that can’t come without Y, or Y that can’t come without X?“. Philosophers like Aristotle thought that “both the bird and egg must have always existed“. Evolutionary biologists came up with the egg as the answer saying that “The zygote cell is the only place where DNA mutations could produce a new animal, and the zygote cell is housed in the chicken’s egg. So, the egg must have come first“. Recently British scientists from Sheffield and Warwick universities, discovered that formation of eggs is only possible in the presence of a protein found in chicken’s ovaries. This protein, called ovocledidin-17 (OC-17), speeds up the development of the egg’s hard shell. That is to say that the chicken came first.