Did the chicken or the egg came first?

Talking of whether the chicken or the egg came first, it has always been a highly argumented topic among everyone and especially, the scientists.
Research shows that certain protein needed to produce the egg shell (known as OV-17) can only be found in in the ovaries of chickens. Does this mean the chicken came first? No. It's the egg which came first. It is now believed that two species of birds which could have lived before with similar traits of chicken mated and the came came.