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IN RETROSPECT
The Origin of Life

“Oparin belongs in the pantheon of the twentieth century’s greatest scientists for pro-viding a foundation for understanding early molecular evolution.” –  write in  the Nature Clifford P. Brangwynne of MPI of Molecular Biology and Genetics in Dresden and Anthony A. Hyman of Princeton University.
(see Brangwynne, C. P and Hyman, A.A. IN RETROSPECT: The Origin of Life.  | NATURE | VOL 491 | P.  524 – 525.)

Below follow excerpts from this article.

 “No religious or philosophical sys¬tem, no outstanding thinker ever failed to give this question seri¬ous consideration.” So wrote Aleksandr Oparin more than 75 years ago, about the quintessential conundrum of how life self-assembled from inanimate components. The Soviet biochemist’s answer is his book The Origin of Life (1936). Roughly based on a pamphlet he published in 1924, this book is an enormous contribution to our under¬standing of life’s improbable beginnings. In it, Oparin argues that conditions on early Earth nurtured the synthesis of amino acids and their assembly into protocells. Nearly 20 years after the book’s publication… Stanley Miller and Harold Urey tested Oparin’s hypothesis in a lab at the University of Chicago in Illinois. They sent a continuous electric current through a glass vial contain¬ing water, hydrogen, methane and ammonia...(and) a substantial amount of the carbon had been converted into complex macromolecules, including many amino acids. This ‘Miller–Urey’ experiment con¬firmed the significance of Oparin’s ideas, and Miller duly referenced The Origin of Life. 

Oparin’s work thus played a seminal part in the formulation of our modern ideas of life’s conception. His ideas on the organiza¬tion of cells and first stirrings of life con¬tinued to attract an important audience.

Today, the primary legacy of The Origin of Life is the Miller–Urey experiment, but the synthesis of amino acids took up just part of the book. Oparin went on to describe a mechanism by which macromolecules would self-assemble into large liquid-like structures that he called “complex coacervates” — what today might be called colloidal assemblies. He suggested that these protocells were a key step in the origin of life. However, given the uncertainty at that time about the nature of biological macromolecules, it was unclear exactly how these colloids might form. 

…current cell and molecular biology provides a new perspective on the feasibility of life beginning from liquid-like macromolecular assemblies, suggesting that Oparin might have been more correct than he thought. Many macromolecules have weak multivalent interactions with other macromolecules, which means they have several sites at which interaction can occur. RNA itself is a flexible, extended, dynamic molecular chain; the interactions between it and other molecules are typically numerous and weak. These properties are sufficient for macromolecules to self-assemble into liquid-phase droplets, like Oparin’s coacervates. Recent work on RNA compartmentalization and catalysis in liquid droplets provides addi¬tional support for Oparin’s concept of primi¬tive protocells in a primordial ‘RNA world’.

Oparin belongs in the pantheon of the twentieth century’s greatest scientists for pro¬viding a foundation for understanding early molecular evolution. He believed that natu¬ral selection had “completely wiped off the face of the Earth all the intermediate forms of organization of primary colloidal systems and of the simplest living things”. Three-quarters of a century before Oparin, Charles Darwin noted that such primitive life forms would be a poor match for contemporary, highly evolved ones. But Darwin also wrote that relatively less-evolved species — “anom¬alous forms … living fossils” — often come down through the ages, against all the odds.

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