Was First Life on Earth Triggered by Clay?

In the early 1990s, Jack Szostak of Harvard Medical School began investigating the molecular origins of life in order to understand how chemicals combined to form the first living organisms on primitive Earth. Inspired by Tom Cech and Sidney Altman’s discovery that RNA could catalyze chemical reactions inside cells (which later earned them a Nobel Prize), Szostak began to explore RNA’s ability to catalyze its own reproduction.

Building on earlier work by other scientists, Szostak and colleagues began experimenting with a clay mixture common on early Earth called montmorillonite, which was found to catalyze the chemical reactions needed to make RNA.

So, did life originally spring from clay as some creation myths assert? 

Not necessarily, but it does provide a possible mechanism for explaining how life initially arose from nonliving molecules. Szostak's team at the Howard Hughes Medical Institute and Massachusetts General Hospital showed that the presence of clay aids naturally occurring reactions that result in the formation of fatty sacks called vesicles, similar to what scientists expect the first living cells to have looked like. Further, the clay helps RNA form. The RNA can stick to the clay and move with it into the vesicles. This provides a method for RNA's critical genetic information to move inside a primitive cell.

"It's exciting because we know that a particular clay mineral helps with the assembly of RNA," Szostak said. "There certainly would have been lots of environments on early Earth with clay minerals. It's something that forms relatively easily as rocks weather."

The researchers also found that the clay expedited the process by which fatty acids form vesicles that could serve as cell membranes. When RNA and fatty acids were mixed with the montmorillonite, the clay seemed to help transport the RNA inside the vesicles, forming a cell-like structure. Szostak and his team surmised that a similar process could possibly have led to the creation of the first cell.

Posted by Casey Kazan.

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