Infertile Clay May Have been the Birthplace of Life on Earth
Clay may just seem like an infertile blend of minerals, but this substance may have been the birthplace of life on Earth. Scientists have discovered that complex biochemical may have originated in clay, which could have led to the origins of life.
In simulated ancient seawater, clay forms a hydrogel. This mass of microscopic spaces is capable of soaking up liquids like a sponge. Over billions of years, chemicals confined in those spaces could have carried out the complex reactions that formed proteins, DNA and eventually all the machinery that makes a living cell work. In fact, clay hydrogels could have confined and protected those chemical processes.
"We propose that in early geological history clay hydrogel provided a confinement function for biomolecules and biochemical reactions," said Dan Luo, one of the researchers, in a news release.
All of this, though, is just theory. In order to test it, the scientists created clay hydrogel. They found that amino acids and other biomolecules could have formed in primordial oceans, drawing energy from lightning or volcanic vents. These acids could have been protected by the clay since biomolecules have a tendency to attach to its surface. In addition, cytoplasm, which is the interior environment of a cell, behaves much like a hydrogel.
That's not all the scientists found. Using geological history, they found that clay first appeared just at the time biomolecules began to form into protocells, which are cell-like structures. Eventually, they formed membrane-enclosed cells. This history matches up nicely with biological events.
That said, exactly how these biological machines evolved remains to be explained. For now, the researchers are planning to study exactly why a clay hydrogel works so well. This could help with drug manufacturing where large quantities of proteins and thus, a lot of hydrogel, are necessary.
The findings are published in the journal Scientific Reports.