New model based on lipid molecules

REHOVOT, ISRAEL--June 5, 2000-- One of the greatest mysteries, which continuously fascinates many scientists worldwide, concerns the way by which life emerged on primeval Earth. The accepted notion is that prior to the appearance of living organisms, there was a stage of chemical evolution, which involved selection within inanimate chemical mixtures. This is thought to have eventually led to the crucial moment, when self-replicating molecules arose. As self-replication is a most fundamental characteristic of living entities, such an event is often defined as the birth of life.

Self-replication of molecular systems is often viewed in the context of information content. Many scientists believe that life began with the spontaneous emergence of biopolymers, such as proteins or RNA, where information is stored in the sequence of chemical units. Experiments mimicking the conditions on Earth billions of years ago have shown how such chemical units, e.g. some of the building blocks of proteins and RNA, could appear spontaneously. Yet, the emergence of proteins or self-replicating RNA molecules remained enigmatic.

This started Prof. Doron Lancet of the Crown Human Genome Center in the Weizmann Institute of Science, and his students, Daniel Segre and Dafna Ben-Eli, on a journey leading to alternatives to proteins and RNA. They have developed a model, suggesting a new route for the origin of life, based on lipid molecules. This model is described in an article published in a recent issue of the Proceedings of the National Academy of Science, USA.

Lipids are oily substances, known as chief ingredients of the cell's membranes. Lipids have two different aspects − one hydrophilic (water-attracting), and the other hydrophobic (water-repelling). They get readily synthesized under simulated prebiological conditions, and because of their bipartite nature, have the tendency to spontaneously form s
'"/>

Contact: Jeffrey J. Sussman
jeffrey@acwis.org
212-895-7951
American Committee for the Weizmann Institute of Science
4-Jun-2000