Clay is seen as the primordial material of life in various cultures and religions. We have biology to explain how life comes to be, but could the stories of old hit closer to the mark?
In a paper written to commemorate the work of Ned Seeman, inventor of the field of DNA nanotechnology, UC Santa Barbara biophysicist emerita Helen Hansma outlines her longstanding idea that that primitive life, in pre-cellular arrangements that evolved into our cells, may still exist. The paper appeared in the journal.
Hansma's hypothesis has been proposed many times before. The "RNA World" and the "Metaboloism First" concept suggest that life began out of chemical reactions. The "pizza" hypothesis says that life could have come from organic biomolecules. Life may have started on iron-rich clays.
When Hansma first came up with the idea, she didn't want to figure out how life evolved. She was a research biophysicist and a program director at the National Science Foundation when she played with her toys.
She said in an article that she thought "this would be a good place for life to originate."
Her idea claims that life could have been created from non-living material if it had been corralled between layers of mica. The environment allowed for the free exchange of water and other substances that would become essential to cells.
She said that the surfaces of the sheets were a great place for molecules to grow and processes to develop. The mica was used as a scaffolding andreaction chambers. Hansma said that the advantage of mica clays over montmorillonite is that they are non-swelling and give a more stable environment. Montmorillonite sheets are held together by smaller salts, which causes them to shrink and swell during wet-dry cycles.
The mica clay hypothesis is supported by the fact that the cells in living creatures have high concentrations of potassium, which makes it a more likely habitat than montmorillonite.
Where would the energy to interact and sustain itself come from, without the biochemical energy that powers our bodies? Hansma suggests that the opening and closing of the mica sheets as water flowed in and out could have been a mechanical energy source.
She said that the open-and-shut movements seemed to be a way of squashing the molecule together. The proximity could have promoted interactions between the molecule. Different interactingmolecules would combine to form a single molecule. The group of big molecule would eventually be wrapped around the Lipids in the mix
Some of the arguments in Hansma's hypothesis can be found in micaceous clay and the mineral's affinity for biomolecules and other factors.
Hansma says that "life imitates mica in many ways."
More information: Helen Greenwood Hansma, DNA and the origins of life in micaceous clay, Biophysical Journal (2022). DOI: 10.1016/j.bpj.2022.08.032 Journal information: Biophysical Journal
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