Which came first:The chicken or the egg?

Yes ! It's that old riddle that sparked many arguments through years - was it the chicken or the egg that came first? It's a really tricky question because you need a chicken to lay an egg,but chickens come from eggs,leaving us with this feathery life that apparently has no starting point. Thankfully,there is no need to keep brooding over this forever. This is a riddle which we can unscramble with the principles of evolutionary biology. Let's get cracking.

The first were the chicken eggs. But wait - weren't there some scientists who claimed that the chicken came first? This claim came from some researchers studying how chicken eggshells form. Eggshell is mostly made from Calcium Carbonate (CaCO3). Hens get their supply of calcium for eggshell production from dietary sources (calcium rich seafood shells,such as oyster). To form a shell,the calcium needs to be deposited in the form of CaCO3 crystals,and hens rely on specific proteins that enable this process. One such protein,called ovocleidin-17 (OC - 17),is only found in the ovary of the chicken,leading to the suggestion that the chicken must have come before the chicken egg,since without OC - 17,there can be no chicken egg formation. 

Interestingly,it seems that this protein is responsible for speeding up the rate of eggshell production,enabling hens to build an egg from the scratch and lay it within a 24-hour timeframe. 

So can we lay this age old conandrum to rest? Or are scientists and philosophers still scrambling to find an answer? Based on evolutionary evidence,we are on Team Egg....