Which Came First – The Chicken or the Egg?

It’s a question that has perplexed humanity from the Ancient Greeks all the way to the 21st century and we’re still dying to know: Which came first, the chicken or the egg?<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

The question would be simple if we took it literally.  Egg-laying animals existed long before chickens came about so technically the egg came before the chicken.  But this question, better worded as the chicken or the chicken egg, focuses more on the cyclical cause and consequence.  That is, if a chicken is born from an egg, where did the egg come from?  Another chicken presumably, which too must have come from an egg.  So which came first?

On the one side we have team chicken.  Research suggests that the protein essential for the formation of chicken eggs, called OV-17, is only found in chicken ovaries.  Without it, the chicken egg shell could not be formed.  So without a chicken, you technically can’t get a chicken egg.

But this all depends on the nature and definition of a chicken egg in the first place.  After all, is a chicken egg an egg laid by a chicken or one that simply contains a chicken?  Obviously the OV-17 bearing chicken had to come from somewhere.  But if an elephant laid an egg from which a lion hatched, would it be an elephant egg or a lion egg?  This leads to the other side of the story: team egg.

During reproduction, two organisms pass along their genetic information in the form of DNA.  But the replication of this DNA is never 100% accurate and often produces minor changes for the new organism.  These small mutations in DNA over thousands of generations create new species.  But these genetic mutations must occur in zygote, or initial cell.

So a creature very similar to a chicken, which we could call a proto-chicken would’ve mated with another proto-chicken and because of a small genetic created the first chicken which grew in an egg.  So the egg came first?  Well, team chicken might argue that this was simply a chicken growing inside of a proto-chicken egg.  However, no one mutation can ever really constitute a new species.  Even though we humans like to classify all creatures into different groups and names, this is based on how things currently are and now how they were millions of years ago.

The process of evolution is so gradual that no one proto-chicken to chicken birth could really be considered a new species at the time, much like how dogs have come from wolves.  As humans began to interact with and domesticate wolves, there was no single point where a wolf gave birth to a dog.  But rather, as particular traits came about from selective pressures such as choosing wolves who are not afraid of humans, or ones that were less aggressive, over many generations we can see big genetic and behavioral trait differences.

So where does this leave us?  We’re left with two scenarios: some early egg-laying species gradually lead to the creation of proto-chicken which laid proto-chicken eggs.  In one of these eggs there was a mutation causing a slight change in selective advantage and this was ultimately the first chicken which then went on to lay chicken eggs.  In this case, the chicken technically came first.  Or we have a proto-chicken that gave birth to what we would call a chicken inside of what we would classify as a chicken egg and as such, the egg came first which brings us back to the nomenclature and question which is “what is a chicken egg”, which is a fairly meaningless question.  But at the end of the day, what we can all agree on is that regardless of whether it was a chicken egg or a proto-chicken egg, the first true chicken came from an egg.

The egg came first.

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