(Santa Barbara, Calif.) Life may have begun in the protected spaces inside of layers of the mineral mica, in ancient oceans, according to a new hypothesis.
The hypothesis was developed by Helen Hansma, a research scientist with the University of California, Santa Barbara and a program director at the National Science Foundation. Hansma will present her findings at a press briefing on Tues., Dec. 4, at the annual meeting of the American Society for Cell Biology in Washington, D.C.
The Hansma mica hypothesis proposes that the narrow confined spaces between the thin layers of mica could have provided exactly the right conditions for the rise of the first biomolecules effectively creating cells without membranes. The separation of the layers would have also provided the isolation needed for Darwinian evolution.
Some think that the first biomolecules were simple proteins, some think they were RNA, or ribonucleic acid, said Hansma. Both proteins and RNA could have formed in between the mica sheets.
RNA plays an important part in translating the genetic code, and is composed of nitrogenous bases, sugar, and phosphates. RNA and many proteins and lipids in our cells have negative charges like mica. RNAs phosphate groups are spaced one half nanometer apart, just like the negative charges on mica.
Mica layers are held together by potassium. The concentration of potassium inside the mica is very similar to the concentration of potassium in our cells. And the seawater that bathed the mica is rich in sodium, just like our blood.
The heating and cooling of the day to night cycle would have caused the mica sheets to move up and down, and waves would have provided a mechanical energy source as well, according to the new model. Both forms of movement would have caused the forming and breaking of chemical bonds necessary for the earliest biochemistry.
Thus the mica layers could have provided the support
|Contact: Gail Gallessich|
University of California - Santa Barbara