DNA Origin of Life

Is the “RNA world” hypothesis a good naturalistic explanation for the origin of life?

If you look closely at this blog, you’ll see that I am currently reading  a book called “The Comprehensive Guide to Science and Faith: Exploring the Ultimate Questions About Life and the Cosmos“. Well, there’s an ongoing series of posts about the book at Evolution News, and one of them caught my eye. They are talking about the origin of life, and what’s needed to create life from non-life.

Here is the post from Evolution News.

The article starts by explaining the what is required to show how non-living components could be organized into a living system:

  • plausible biochemical paths from individual bio-building blocks like amino acids or nucleic acids to functional polymers such as proteins and DNA.
  • ways to speed up chemical reactions that are naturally slow.
  • the ordering of amino acids in proteins and nucleotide bases in RNA and DNA that allows them to function properly.

The leading naturalistic explanation to solve these problems is called the “RNA world” hypothesis:

The most popular proposal for the first self-replicating molecule is RNA — where life was first based upon RNA carrying both genetic information (akin to modern DNA) and performing catalytic functions (akin to modern enyzmes), in what is termed the RNA world.

The article lists several problems with the RNA world hypothesis. Dr. Walter Bradley lists two of those problems.

First, the assembly of RNA requires intelligent design:

First, RNA has not been shown to assemble in a laboratory without the help of a skilled chemist intelligently guiding the process. Origin-of-life theorist Steven Benner explained that a major obstacle to the natural production of RNA is that “RNA requires water to function, but RNA cannot emerge in water, and does not persist in water without repair” due to water’s “rapid and irreversible” corrosive effects upon RNA.3 In this “water paradox,” Benner explains that “life seems to need a substance (water) that is inherently toxic to polymers (e.g., RNA) necessary for life.”4

To overcome such difficulties, Benner and other chemists carefully designed experimental conditions that are favorable to the production of RNA. But Robert Shapiro explains that these experiments do not simulate natural conditions: “The flaw is in the logic — that this experimental control by researchers in a modern laboratory could have been available on the early Earth.”5 Reviewing attempts to construct RNA in the lab, James Tour likewise found that “[t]he conditions they used were cleverly selected,” but in the natural world, “the controlled conditions required to generate” RNA are “painfully improbable.”6 Origin-of-life theorists Michael Robertson and Gerald Joyce even called the natural origin of RNA a “Prebiotic Chemist’s Nightmare” because of “the intractable mixtures that are obtained in experiments designed to simulate the chemistry of the primitive Earth.”7 In the end, these experiments demonstrate one thing: RNA can only form by intelligent design.

The second problem is that the RNA world hypothesis is that it requires the existence of a self-replicating RNA molecule in order to get started. But this self-replicator contains a lot of biological information that is beyond the reach of chance to produce:

The most fundamental problem with the RNA world hypothesis is its inability to explain the origin of information in the first self-replicating RNA molecule — which experts suggest would have had to be at least 100 nucleotides long, if not between 200 and 300 nucleotides in length.10 How did the nucleotide bases in RNA become properly ordered to produce life? There are no known chemical or physical laws that can do this. To explain the ordering of nucleotides in the first self-replicating RNA molecule, origin-of-life theorists have no explanation other than blind chance. As noted, ID theorists call this obstacle the information sequence problem, but multiple mainstream theorists have also observed the great unlikelihood of naturally producing a precise RNA sequence required for replication.

Whenever I sit down to write some code or to write a blog post, I can start with one letter, then add another, then add another, until I have a functioning program, or a legible blog post. It might be possible for random chance to make a meaningful word out of 3 letters, like “the” or “hat”. But it’s not possible to make a self-replicating RNA molecule that way. The required sequence is just too long, and every letter has to be just right in order for it to function as a self-replicating system. The simplest self-replicating molecule is extremely complicated.

Anyway, check out the article, and if you want to read all about Walter Bradley (my role model), there is a new book out about him called “For a Greater Purpose: The Life and Legacy of Walter Bradley” which I finished, and it was great.

2 thoughts on “Is the “RNA world” hypothesis a good naturalistic explanation for the origin of life?”

  1. Dr James tour is amazing.

    It is interesting to see how every level from physics to chemistry. Even assembly of information and required interpretation. Each step has impossible odds that require far beyond luck to occur. And to have them all occur in a small narrow time window, such as the lucky moment of rna self assembling before it is naturally broken down by its environment.

    It is beyond proof against abiogensis.

    Liked by 1 person

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