Chicken or Egg Part Two

You have probably had people argue about which came first: DNA or RNA. But have you ever wondered the same about DNA and Proteins? Let’s ponder today.

What Came First DNA or Protein?

It may seem a bit counter-intuitive at first, but the answer is Protein.

Going back to Earth’s early history (long long long before than Once upon a time stories), before the first single celled organisms appeared on Earth, the oceans were rich in inorganic minerals and chemicals, and the atmosphere was rich in gases like Nitrogen, Methane, Ammonia, and Carbon Dioxide. As a result of the intense heat from electric discharges - lightning - these inorganic compounds combined to form a cocktail of more complex organic molecules.

In their milestone experiment, Stanley Miller and Harold Urey simulated pre historic conditions of Earth in a glass flask. They put in a mixture of water, methane, ammonia, and hydrogen in the flask. Used electric sparks as artificial lightning, heated and condensed the mixture. After a day of continuously running their experiment, they found all 20 amino acids in the mixture!

It is thus largely believed that even if DNA (or RNA) was required to give rise to self replicating living creatures, proteins were present long before them. Now thinking about it, it’s not counter-intuitive at all!