Scientists' second look at role of `dust' in forming life on Earth. Clay may have triggered processes that led to creation of living organisms, raising a possibility that minerals had their own life-forms

And the Lord God formed man of the dust of the ground, and breathed into his nostrils the breath of life; and man became a living soul.-- Genesis 2: 7 What seemed plausible to our ancestors, and continues to persuade many believers today, has largely been dismissed by most scientists as pure parable. But a cadre of researchers studying the origin of life on Earth are convinced that the role of minerals in general, and clay in particular, was far more than figurative.

They argue that considerable circumstantial evidence supports the contention that clay played an intimate role in the formation of organic life.

A number of the advocates of this minority view explained their reasoning at a symposium held Tuesday at the National Aeronautics and Space Administration's (NASA) Ames Research Center here.

``This is an exciting time in origin-of-life work. We are seeing a coming together of organic and inorganic research in a synergistic way,'' explains David Deamer, a biologist at the University of California, Davis.

The dominant scientific view of the creation of life pictures the first self-reproducing molecules arising in a ``primordial soup'' rich in organic materials. These materials, it is thought, were created in the planet's primitive atmosphere rich in ammonia and methane.

This view was supported by experiments that passed a spark through a mixture of gases thought to duplicate Earth's primitive atmosphere. The experiments found that organic chemicals could be made in abundance.

But more recent geochemical research now suggests that the ammonia and methane required were not all that abundant and would not have lasted long enough to produce the quantities of organic materials necessary for such a process. This made researchers more willing to consider alternative mechanisms.

For some time researchers have known that clay and organic material mix in interesting ways. Clay has been found to be a catalyst in the formation of peptides, primitive proteins, from amino acids. More recently, David White of the University of Santa Clara has found that the addition of small amounts of peptides to the clay-amino acid experiment disproportionately boosts peptide formation.

As a result of experiments of this sort, origin-of-life experts have grown more open-minded about the possibility that clay acted as a catalyst for the production of crucial organic material, may have provided a surface to support early organic molecules, and perhaps even acted as a template for early life forms.

Far more controversial is the argument of organic chemist Graham Cairns-Smith of the University of Glasgow. He speculates that mineral life-forms may have existed and created organic materials for their own, evolutionary purposes.

While cheerfully acknowledging that no hard evidence supports his ``clay-life'' hypothesis, he argues that organic life is too ``high tech'' to have evolved from the simple beginnings now assumed.

Instead, he says it more plausible that organic life got a head start from a ``low tech'' mineral life-form. Professor Cairns-Smith shows microscopic photos of various clays that take on strikingly organic-like forms to lend credence to his ideas.

As scientists have increasingly examined the difference between the living and non-living at the molecular level, distinctions have blurred, agrees Leila Coyne of San Jose State University.

Dr. Coyne, with colleagues at NASA-Ames, has demonstrated that clays can store and transfer energy, one of the characteristics exhibited by living organisms. Her work demonstrates that clays absorb significant amounts of energy from radioactive and ultraviolet sources and release it at room temperature when wetted (particularly in the presence of amino acids) or dried, and when fractured.

``The more science learns what life is, the more reluctant scientists are to define it. It is far easier to say what living things are made of and what they do, than what they are,'' Coyne says.

Mineral systems have been found that exhibit all basic life-functions, such as growth and repair, reproduction, and response to the environment. ``But no single system has been found which exhibits all of them,''she says.

And that is exactly what Cairns-Smith wants to find. Once identified, scientists could determine whether the system is subject to the laws of natural selection. If so, this would provide a powerful boost to his contention. -- 30 --{et

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