A new theory about the chemical evolution of life proposes that simple self-replicating chemical systems rather than complex ones could have been the precursors of living cells more than 3.5 billion years ago. The new theory, published in a recent issue of the Journal of Molecular Evolution, was developed by David White, an assistant professor at the University of Santa Clara, Calif.
White proposes that the first chemical ancestors of life were themselves ‘alive’ only in the sense that they could reproduce themselves and may have been far simpler than previously believed. The prevailing theory of the chemical evolution of life holds that natural energy, such as lightning, sunlight, and heat, interacted with the atmosphere, soils, and oceans of primordial Earth. The continuous interaction and evolution over millions of years eventually produced complex chemical systems that could reproduce themselves and that led to the first living cells. The problem lay in getting the right chemical building blocks together in the right place at the right time. The process that led to living cells is easier to explain, however, if the necessary components are simple and few in number.