What came first, the chicken or the egg? The definitive answer

It is a question that has vexed philosophers since the Greeks. But it seems we may now have the answer to the beguilingly simple question: "Which came first?" It's the egg.

This reassuring conclusion was the work of an expert panel including a philosopher, geneticist and chicken farmer.

"Whether chicken eggs preceded chickens hinges on the nature of chicken eggs," said panel member and philosopher of science David Papineau at King's College London.

"I would argue it's a chicken egg if it has a chicken in it. If a kangaroo laid an egg from which an ostrich hatched, that would surely be an ostrich egg, not a kangaroo egg. By this reasoning, the first chicken did indeed come from a chicken egg, even though that egg didn't come from chickens."

The oldest recorded reference to the childish conundrum goes back to a collection of essays and discussions by the Greek historian Mestrius Plutarchus, born in 46AD. In a section entitled Whether the Hen or the Egg Came First he suggested that the question was already well established: "The problem about the egg and the hen, which of them came first, was dragged into our talk, a difficult problem which gives investigators much trouble."

Plutarchus also hinted at the puzzle's greater significance: "Sulla my comrade said that with a small problem, as with a tool, we were rocking loose a great and heavy one, that of the creation of the world."

Whether the panel solved that debate is not clear, but they were unanimous on the correct chicken/egg pecking order. John Brookfield, an evolutionary geneticist at the University of Nottingham said the solution involves piecing together the speciation event in which chickens first evolved.

He imagines two non-chicken parents getting together and giving rise to the first individual of a new species because of a genetic mutation. "The first chicken must have differed from its parents by some genetic change, perhaps a very subtle one, but one which caused this bird to be the first ever to fulfil our criteria for truly being a chicken," said Prof Brookfield.

"Thus the living organism inside the eggshell would have had the same DNA as the chicken that it would develop into, and thus would itself be a member of the species of chicken," he added.

Will the panel be conducting other chicken-related enquiries, such as why did the chicken cross the road? Prof Brokfield refused to comment.

The debate was organised to coincide with the launch of Chicken Little on DVD.