Did life on Earth emerge from clay?

There's a longstanding theory that life first emerged in pools of water. But if scientists from Cornell are correct, it may have first taken root inside of clay.

Clay doesn't seem like a likely place for the genesis of life. Deposits of the stuff are primarily composed of infertile phyllosilicate minerals and water. But as the new study proposes, early clay hydrogel may have provided an effective living space for biomolecules and biochemical reactions. These confinement areas may have been where life first took root. Or at the very least, clay may have been a provider of the complex biochemicals that made life possible.

Hydrogel is a kind of clay that contains a bunch of microscopic spaces capable of soaking up liquids like a sponge. Given enough time, the chemicals confined in those spaces could have carried out the same reactions that form proteins, DNA, and everything else involved in making living cells work.

In experiments involving simulated seawater, a team led by biological and environmental engineering Professor Dan Luo showed that protein synthesis is possible in the hydrogel.

"Fill the spongy material with DNA, amino acids, the right enzymes and a few bits of cellular machinery and you can make the proteins for which the DNA encodes, just as you might in a vat of cells," noted Luo in a statement.

Interestingly, the geological history shows that clay first emerged on Earth, in the form of silicates leach from rocks, around the same time biomolecules began to form into protocells, and eventually membrane-enclosed cells. "The geological events matched nicely with biological events," said Luo.

For now, the exact biological and chemical mechanisms responsible for these exact transformations are still unknown. The research group will next turn its attention to why clay hydrogel works so well.

You can read the entire study here (pdf).

Image: Galyna Andrushko/Shutterstock.