Origin of Life

This post will provide a final discussion of an article in Scientific American entitled “A Simpler Origin for Life” by Robert Shapiro. Part I explained why the Miller-Urey experiment and the DNA-first hypothesis is deficient. In Part II, I explained Shapiro’s apt criticisms of the RNA-world hypothesis. Those who have abandoned the RNA-world hypothesis still seek a self-replicating molecule to qualify as the climax of chemical-origin of life scenarios–the “pre-RNA world.” However, Shapiro observes not only that “no trace of this hypothetical primal replicator and catalyst has been recognized so far in modern biology,” but also that “the spontaneous appearance of any such replicator without the assistance of a chemist faces implausibilities that dwarf those involved in the preparation of Read More ›

Writing in Scientific American Robert Shapiro recounts many criticisms of popular models for the chemical origin of life. Part I recounted why many origin of life theorists reject the possibility that DNA was the first genetic molecule. As noted, Shapiro even takes aim at those who suggest that the Miller-Urey experiment chemistry was important for forming prebiotic molecules on meteorites because studies of these meteorites show “a bias toward the formation of molecules made of fewer rather than greater numbers of carbon atoms, and thus shows no partiality in favor of creating the building blocks of our kind of life.” Due to these deficiencies, Shapiro then notes that increasing numbers of prebiotic chemists now turn to RNA as the first Read More ›

In an article titled “A Simpler Origin for Life” — a title which hides the implication of the article, Robert Shapiro, writing in Scientific American, highlights many problems with chemical origin of life scenarios. Shapiro quotes Richard Dawkins on his worship of the first self-replicating molecule and says “[a]t some point a particularly remarkable molecule was formed by accident. We will call it the Replicator.” (emphasis in original) That’s “Replicator” with a capital “R“. But, as Shapiro explains, the conventional explanation is not nearly so simple: Unfortunately, complications soon set in. DNA replication cannot proceed without the assistance of a number of proteins — members of a family of large molecules that are chemically very different from DNA. Proteins, like Read More ›