It’s been used for ages as building material, and for decoration. It’s used today for electronic components and tooth-polishing. It’s mica, and according to UCSB researcher Helen Hansma, the mineral could also have been instrumental in the beginnings of life on Earth.

Hansma’s hypothesis, which she presented at the annual meeting of the American Society for Cell Biology in Washington on Tuesday, proposes that the unique properties of mica may have created the optimal environment for the development of the earliest forms of life.

There are several theories of the origins of life, Hansma said from her Washington office, where she spends part of her time as program director for the National Science Foundation. One well-known idea is that life originated in the oceans — a prebiotic soup of simple molecules randomly floating around. A lesser-known notion, she said, is the pizza hypothesis, which suggests that these biomolecules originated on the Earth’s crust.

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The random soup model leaves molecules open to the elements, according to Hansma. And the pizza hypothesis can’t explain how the earliest biomolecules were able to come up with enough water to form stable bonds between them.

Not to be left out of the smorgasbord, Hansma offered another look at the origins of life.

“I call it the sandwich filling model,” she said.

The key is in the structure of mica, a mineral with which Hansma is deeply familiar.

“I developed a passion for mica in the late 1980s when I was working at UCSB on atomic force microscopy,” she said. “Mica is quite an amazing mineral.”

Mica is unique in that its surface is so atomically smooth it is used in preparing samples for viewing with the atomic force microscope, an instrument that can scan samples down to less than a nanometer. Mica is also arranged in nanometer-thin layers and, according to Hansma, it’s the spaces within these layers that provided the kind of incubator that the first biomolecules needed to survive. With sheets of mica floating in the ocean, the molecules would have both the water, and the relative safety from the elements they needed to evolve.

“Some think that the first biomolecules were simple proteins, some think they were RNA, or ribonucleic acid,” Hansma said. “Both proteins and RNA could have formed in between the mica sheets.” Similarities in the structure, composition and electrical charge between RNA and mica further suggest that mica acted as a cell wall before the molecules organized and developed their own membranes.

The heating and cooling of the day-to-night cycle plus the wave action could have provided enough movement and energy to create and break the bonds and molecules needed for the necessary chemistry of life, she added.

What’s just as interesting is how Hansma came by her hypothesis – her fascination with mica extends beyond the lab.

“I was trying to make a centerpiece decoration for a wedding last spring,” she said. “There were no scientific thoughts in my mind at all.”

Using a dissecting microscope — an instrument commonly used by hobbyists for viewing coins and stamps — Hansma encountered what she called “organic crud” between layers of mica.

“It occurred to me that this would be a good place for life to originate — between these sheets that can move up and down in response to water currents which would have provided the mechanical energy for making and breaking bonds.” From there, she said, the first biomolecules would have gotten a good start before spreading out into the world.

Tuesday’s discussion won’t be the only one the biophysicist has scheduled on her new idea. In January she returns to California to discuss the hypothesis with a small group of researchers interested in the origins of life and in February she’ll be presenting a talk in Long Beach, at a biophysical society meeting.

“I’m excited to see where it goes from here,” Hansma said. “I’m curious to see what parts of the hypothesis are controversial.”