Scientists believe they have cracked the age-old riddle – the CHICKEN really did come BEFORE the egg.
Researchers found that the formation of egg shells relies on a protein that is only found in a chicken’s ovaries.
Therefore an egg can only exist if it has been inside a chicken – thereby proving chickens must have come first.
The protein – called ovocledidin-17 (OC-17) – acts as a catalyst to speed up the development of the shell.
The hard shell is needed to house the yolk and its protective fluids while the chick develops inside.
Boffins now believe that before an egg can be formed it must have needed the OC-17 protein only found in the ovary of a chicken.
The discovery has been revealed in the paper ‘Structural Control of Crystal Nuclei by an Eggshell Protein’.
Scientists from Sheffield and Warwick universities used a super computer to ‘zoom in’ on the formation of an egg.
The computer, called HECToR based in Edinburgh, revealed OC-17 is crucial in kick-starting crystallisation – the early stages of the formation of a shell.
The protein coverts calcium carbonate into calcite crystals which makes up the egg shell.
Calcite crystals are found in numerous bones and shells but chickens form them quicker than any other species – creating six grams (0.2oz) of shell every 24 hours.
Dr Colin Freeman, from Sheffield University’s Department of Engineering Materials, said: ”It had long been suspected that the egg came first but now we have the scientific proof that shows that in fact the chicken came first.
”The protein had been identified before and it was linked to egg formation but by examining it closely we have been able to see how it controls the process.
”It’s very interesting to find that different types of avian species seem to have a variation of the protein that does the same job.”
Professor John Harding, also of Sheffield’s Department of Engineering Materials, said the discovery could have other uses.
He said: ”Understanding how chickens make egg shells is fascinating in itself but can also give clues towards designing new materials and processes.
”Nature has found innovative solutions that work for all kinds of problems in materials science and technology – we can learn a lot from them.”
