rna

HURDLE NUMBER 2. THE RNA HURDLE.

DNA is the molecule that carries the genetic information, “telling” the body how to grow and function. RNA is a simpler version of DNA.

If life could have emerged from a primordial soup, then it would either have to emerge in the form of Protein, or DNA, or RNA. These are considered by origin of life scientists to be the only three possible options.

We have to rule out proteins, because proteins cannot reproduce themselves.

This leaves us with DNA or RNA. RNA is the simpler molecule, and therefore origin of life scientists believe that the most feasible way forward for evolution is if RNA forms in the primordial soup, and reproduces itself in more and more complex formats until natural selection takes over, and evolution commences.

Unfortunately (as origin of life scientists will readily admit) there are vast, absolutely insurmountable hurdles to this above scenario. To illustrate these hurdles, here are some quotes from authoritative sources:-

This quote is from the book Life From an RNA World by Michael Yarus (Professor Emeritus, Dept. Molecular, Cellular, and Developmental Biology, University of Colorado), published by Harvard University Press, 2010, page 53:-

Yarus tells us that “Though nucleobases are easy to make, putting together nucleic acids - - - - has so far proven impossible”

(My comment:- “Nucleobases” are the nucleotide bases (or monomers) that are the fundamental building blocks of DNA or of RNA. “Nucleic acids” are lengths of RNA or DNA.)

The next quote comes from the book Seven Clues to The Origin of Life by A.G. Cairns Smith (Senior Lecturer in Chemistry at The University of Glasgow), published by Cambridge University Press, reprinted 1991, page 45.

“Nucleotides - - - have yet to be made under conditions that are realistic simulations of primitive Earth conditions.”

(My comment:- Nucleotides are the building blocks of DNA and RNA.)

The next quote is from the book Signature in The Cell – DNA and The Evidence For Intelligent Design by Stephen C. Meyer (Ph.D. from Cambridge University in Philosophy of Science), published by HarperOne, 2009, page 322:-

Meyer quotes Leslie Orgel (Senior Fellow and Research Professor at the Salk Institute for Biological Studies in La Jolla, California, where he directed the Chemical Evolution Laboratory.) “The de novo appearance of oligonucleotides (ie:- specific sequences of nucleotides) on the primitive Earth - - - (would have been) - - - a near miracle.”

The next quote comes from from the book Genetic Takeover and The Mineral Origins of Life by A.G. Cairns Smith (Senior Lecturer in Chemistry at The University of Glasgow), published by Cambridge University Press, reprinted 1987, pages 56 to 59:-

“Pre-vital nucleic acids are highly implausible.”

Then Cairns Smith lists reasons why this is so:-

(A). Precursors of nucleotides had to be in concentrated form (unlikely).

(B). The precursors of nucleotides “must have then been separated from the confusing jumble of similar molecules that would also have been made.”

(C). “Bases and sugars must now have come together - - - they must have been induced to react to make nucleotides. There are no known ways of bringing about this thermodynamically uphill reaction in aqueous solution.” He then explains that, even by “dry phase synthesis”, there is no known way to condense pyrimidine bases and ribose to give nucleotides.

(D). He then points out that pH, temperatures etc. must all be just right for nucleotides to form, and that ultraviolet light, or radicals produced by the ultraviolet light will have “highly destructive effects on nucleic acid-like molecules” Cairns Smith then comments:-“A nucleotide is too complex and metastable (ie:- chemically unstable) a molecule for - - - - easy synthesis.”

(My comment:- I should provide definitions of some of the terminology used in the above quote:- Nucleotides (which are the building blocks of RNA and DNA) include a nucleoSIDE joined to ribose (which is a type of sugar). Pyramidine is one of the four nucleosides used to form RNA and DNA.

The next quote is from the book Origins: A Skeptics Guide To The Creation of Life on Earth – by Robert Shapiro (Professor of Chemistry at New York University), published by Heinemann, 1986, page 186:-

Shapiro discusses the steps required on the prebiotic Earth to form a replicating molecule of RNA:- “Many steps would be required which need different conditions and therefore different geological locations. The chemicals needed for one step may be ruinous to others (ie:- ruinous to other steps further down the line). The yields are poor, with many undesired products - - - - It would be necessary to invoke some imagined process to concentrate the important substances and eliminate the contaminants. The total sequence (ie:- of chemical procedures) would challenge our credibility, regardless of the time allotted for the process.”

The next quote is from the book The Origin of Life and Evolutionary Biochemistry, edited by K Dose (Inst. Fur Biochemie, Universitat Mainz, Germany) and S.W. Fox (Inst. for Molecular and Cellular Evolution, University of Miami, Florida) et al, published by Plenum Press, NY and London, 1974. The article in this book that I am quoting from is The Coacervate-in-Coacervate Theory of The Origin of Life by Vladimir J.A. Novak. Czechoslovak Academy of Sciences, Prague:-

“The constituents of nucleic acids (ie:- RNA and DNA) could - - - have originated in a chemical, abiotic manner - - - - - Their organization into nucleic acid molecules is possible only in the presence of a suitable enzyme (polymerase), however,”

(My comment:- In other words, assuming that the nucleotide bases are available, in order for them to “string together” to form a “chain” of RNA, an enzyme (which is a form of protein) is required.)

The next quote comes from the book Blueprint For a Cell: The Nature and Origin of Life by Christian de Duve, Professor Emeritus at The Rockefeller University, and President of the International Institute of Cellular and Molecular Pathology. Published by Neil Patterson Publishers 1991, page 133:-

“The construction of an RNA molecule - - - - requires - - - - 30 to 40 enzymes”

(My comment:- These 30 to 40 enzymes would not have been available on the prebiotic Earth.)

My comment on The RNA Hurdle:- The above quotes make it clear that the emergence of RNA on the prebiotic Earth is effectively a chemical impossibility.