New research suggests life on Earth may not have rained down from the heavens after all; but rather rose up from the ground.
A research team believes life could have formed in Earthly clay, and complex biochemicals may have made it possible, a Cornell University news release reported.
"We propose that in early geological history clay hydrogel provided a confinement function for biomolecules and biochemical reactions," Dan Luo, professor of biological and environmental engineering and a member of the Kavli Institute at Cornell for Nanoscale Science, said.
The researchers simulated seawater from Earth's early days and found it contained hydrogels, which are "a mass of microscopic spaces capable of soaking up liquids like a sponge."
The team believes chemicals trapped in the hydrogel's spaces could have been protected while it underwent complex chemical reactions over billions of years; these reactions could have eventually led to the creation of proteins, DNA, and eventually living cells.
In order to test this theory, the team attempted protein synthesis within a lab-made hydrogel. They found that when filled with the right combination of amino acids, enzymes, DNA, and cellular building blocks; proteins perfect for DNA coding will form.
The team made the discovery while searching for a cheap hydrogel to be used in prescription drug manufacturing. They noticed clay had the ability to form a "dirt cheap" protein-forming hydrogel. The researchers realized the discovery could have deeper implications than they had originally set out to find.
Past studied have found life could have developed in ancient oceans, but researchers could not explain how amino acids and other biomolecules collided often enough to form higher life forms and had adequate protection. The presence of hydrogels could be the explanation they were looking for.
Clay would make sense as life's origin because biomolecules easily attach to its surface. Researchers have observed that cytoplasm (the inner workings of a cell) behave in a similar to a hydrogel, and protects delicate DNA.
"As further evidence, geological history shows that clay first appeared - as silicates leached from rocks - just at the time biomolecules began to form into protocells - cell-like structures, but incomplete - and eventually membrane-enclosed cells. The geological events matched nicely with biological events," the news release reported.
Researchers still need to explain how the cells continued to evolve.