How Life Began on Earth

By Shlomo Maital   

    Have you ever wondered how life on Earth began?  How this incredible complex system of the double-helix DNA, that enables cells to divide and reproduce in exact replicas?

     Researchers have made some progress, recently. (See:  How did the first cells arise?  Carl Zimmer, New York Times, August 21, 2024). 

     Roughly four billion years ago, protocells (rudimentary cells) first came about.  They contained only RNA (ribonucleic acid), a single strand version of DNA (which has two intertwined strands…).  RNA can bend into intricate shapes, turning itself into a tool for cutting or joining other molecules together.  mRNA technology is the basis of, for instance, powerful new COVID vaccines. 

      For over a century, researchers have created RNA droplets – droplets with RNA inside.  If you shake the droplets, they split into two. That may be a clue about how simple cells divide and reproduce.  But there was a problem.  The RNA strands drifted from one droplet to another, and fused together, in a clump, like an oil film on top of the water.

      There is serendipity in sciencd!  A scientist, Aman Agrawal, a chemical engineer, made RNA droplets…he dumped the requisite chemicals into a vial and added purified water, then sealed it.  Months later, he was surprised to see that the vial had a milky color.  That meant the RNA droplets were still there inside, floating there.  They had not clumped or bunched.  Why?  The water coaxed the molecules in the outer layer of the droplets to link together, forming a kind of protective membrance, that kept the RNA droplet intact.   

          Other Nobel scientists replicated this work.  Hypothesis:  Rain falling on the early Earth might have provided the water required to make the intact RNA droplets.   A graduate student took beakers of RNA droplets outside during a storm.  The rainwater resulting made the RNA droplets stable, intact.

           There is still lots more to learn about how life on Earth began.  But little by little scientists are making progress.  And this research is absolutely fascinating….