At science news sites we are still getting an endless stream of very misleading stories trying to suggest progress on the problem of the origin of life, a problem scientists have made no progress on. But there is occasionally some candor from a scientist. A recent press release looked like this.
Recently there was a long interview with chemist Edward Peltzer, the author of many scientific papers that can be read here. The topic is the origin of life. Peltzer speaks far more candidly on this topic than a typical origin-of-life researcher. Peltzer's answers are extremely long-winded, but I will quote some of the highlights.
Peltzer discusses some problems with the famous Miller-Urey experiment producing amino acids, chemicals that are building components of protein molecules. The experiment used the apparatus shown below
Peltzer says this about the experiment:
"The electric discharge process produced racemic amino acids—both D- and L-forms—but living organisms only used the L-form. Likewise, only D-sugars were used by life even though L-sugars also existed. And the Maillard reaction greatly limited the concentration of amino acids in the 'prebiotic soup.' As soon as amino acids were formed, they started reacting with sugars and other unsaturated organic compounds. This reaction consumed the amino acids almost as quickly as they were made and severely limited their availability to make proteins.
If one looks at the percent yield of amino acids from the electric discharge process, they are only a minor product. While the world had praised the Miller-Urey electric discharge experiment as a major breakthrough in origin life research at the time it was announced, this promise has faded with time as all attempts to go further and produce proteins and functional enzymes without a major amount of investigator intervention has proved beyond reach."
Although making some good points, Peltzer fails to discuss some of the main reasons for thinking the Miller-Urey experiment is irrelevant to explaining the origin of life. One reason is that the Miller-Urey experiment used an extremely artificial technological contraption unlike anything that would have existed in the early Earth. Another reason is that the level of electricity bombardment was many, many times greater than any space would have naturally received in the early Earth. Natural lightning occurs in the open air, as a rare event, not anything like what went on in the Miller-Urey experiment (continuous electrical bombardment every other day in a small glass-enclosed space).
Peltzer's discussion above of D and L forms of amino acids will be unclear to most readers, but later on he says a little which helps explain it better:
"First, in abiotic syntheses [experiments like the Miller-Urey experiment], the [experimentally yielded] amino acids are racemic: half of them will be D-amino acids, and half will be L-amino acids. These 'optical' isomers are mirror images of each other, much like our hands are mirror images of each other. The D-amino acids (D for dextro) are the 'right-handed' amino acid, and the L-amino acids (L-for levo) are the 'left-handed' amino acids. In living systems, only the L-amino acids are used and synthesized."
Later on Peltzer explains some of the luck that would be required to get a functional protein of 100 amino acids (all L-amino acids) from some mixture of 30 types of amino acids, only 20 of which are the types of amino acids used by living things. He uses a number of 60, because if you have 30 possible amino acids that can be either left-handed or right-handed, that is 60 possibilities. Peltzer says this:
"Thus, we have 60 amino acids in total. To keep the math simple, let’s ignore the differences in concentrations of the acids and assume that the chance of randomly selecting the L-isomer of a particular amino acid from this mixture is 1 in 60. Thus, the chances of getting the right sequence of amino acids in a protein of 100 amino acids in length by random chance is 1 in 60100 or 1 in 6.53 × 10177. In the vernacular, that would be considerably less than 'slim to none.' But that is just the odds of selecting the amino acids in the correct order; we still have some chemistry to do to combine them in the proper way via peptide bonds. Making proteins via undirected chemical reactions is beyond hard. Based upon these odds, it is impossible."
A skeptic might try to challenge these numbers by saying that not every amino acid in the amino acid sequence of a functional protein has to be exactly as it is. But such an objection has little validity. We know that protein molecules are extremely fragile and sensitive to small changes. Here is a relevant quote: " It seems clear that even the smallest change in the sequence of amino acids of proteins usually has a deleterious effect on the physiology and metabolism of organisms." ( Evolutionary biologist Richard Lewontin, "The triple helix : gene, organism, and environment," page 123). It is true that there are very many sequences of amino acids that correspond to functional protein molecules; but the set of all possible amino acid sequences with a length of 100 amino acids is exponentially larger (more than 1,000,000,000,000,000,000,000,000 times larger) than the set of all possible amino acid sequences of 100 amino acids resulting in functional, useful protein molecules. Similarly, the set of all possible character sequences of about 100 characters is exponentially larger (more than 1,000,000,000,000,000,000,000,000 times larger) than the set of all possible character sequences of about 100 characters that result in useful sentences or paragraphs.
Moreover, Peltzer has calculated using an amino acid length of 100; but the average number of amino acids in prokaryotic proteins (the simpler class of proteins) is much greater, about 300. So the probability of getting any type of functional protein used in the first living thing is actually very much smaller than Peltzer has estimated.
Speaking about the possibility of an accidental origin of life from non-life (abiogenesis), Peltzer makes a good point:
"Now people will argue that given the tremendous size of the ocean and the time involved, there is a tremendous resource for the many possibilities. I would argue that it does us no good to have the essential proteins scattered about the ocean and millions of years apart. We need all of them simultaneously and in the same spot. And that spot is tiny. A typical bacterial cell is very small. They range in size from 0.2 to 2.0 μm in diameter and 2 to 8 μm in length or 63 atto-L to 25 femto-L (63 × 10-18 L to 25 × 10-15 L) in volume. So, time and chance are of no help here."
Later Peltzer flatly states this about abiogenesis (an imagined unguided origin of life from non-life): "Abiogenesis needs an external source of information that random undirected chemical reactions can never provide."
The great majority of Peltzer's comments are intelligent and illuminating, and I have added two of his quotes to my "Candid Confessions of the Scientists" post, which is the largest collection to be found of scientists making the kind of "we don't know so much" confessions they do not ordinarily make. But there is one place in the interview where Peltzer goes very badly wrong. Asked what are the minimum criteria for calling something "alive," Pelzter states this:
"Finally, there has to be a form of genetic information: a blue print for making a new cell or a new organism. Otherwise, reproduction would just be a willy-nilly process of cells splitting when they got too big, with some fragments being viable and others not. Life is much more efficient than that."
Peltzer's claim that there is in genes "a blue print for making a new cell or a new organism" is very incorrect. No such blueprint exists. DNA has been exhaustively analyzed by large billion-dollar projects such as the Human Genome Project. No one ever discovered in DNA any such thing as a blueprint, recipe or program for making an organism, nor did anyone ever discover any such thing as a blueprint, recipe or program for making any cell.
- a specification of the large-scale structure of the human body;
- a specification of the structure of any of the appendages of the human body such as legs or arms or heads;
- a specification of any organ system of the human body;
- a specification of any individual organ of the human body;
- a specification of any of the 200 types of cells in the human body;
- a specification of any of the organelles that are the building components of cells.
- a specification of any of the protein complexes that are smaller than organelles, but larger than individual protein molecules.
It is impossible to even represent in DNA one of the organelles that are the building components of cells. It is also impossible to represent in DNA a cell or an organ or a bone or a body structure. The very low-level coding system used by DNA is utterly incapable of such representations. Similarly, under a primitive coding system such as "thumbs up means I like it" and "thumbs down means I don't like it," you can indicate your approval or disapproval of things. But so primitive a coding system is utterly incapable of transmitting complex construction information such as how to build a house.
The claim that human bodies arise because there is a blueprint for building human bodies stored in cells is a very childish tall tale, as childish as the tall tale that you can build a balloon that will fly you to the moon and back. One reason the claim is childish is the simple fact that blueprints don't build things. Things only get built with the help of blueprints when there is at least one intelligent agent around to read the blueprint and get ideas about to how to instruct things. Deposit at a construction site a heap of building materials and a blueprint, and this will not cause any building to be built. But if you have a construction crew intelligent enough to read the blueprint and get ideas about how to build the building, you can get the construction of a building.
- On page 26 of the book The Developing Genome, Professor David S. Moore states, "The common belief that there are things inside of us that constitute a set of instructions for building bodies and minds -- things that are analogous to 'blueprints' or 'recipes' -- is undoubtedly false."
- Biologist Rupert Sheldrake says this "DNA only codes for the materials from which the body is constructed: the enzymes, the structural proteins, and so forth," and "There is no evidence that it also codes for the plan, the form, the morphology of the body."
- Describing conclusions of biologist Brian Goodwin, the New York Times says, "While genes may help produce the proteins that make the skeleton or the glue, they do not determine the shape and form of an embryo or an organism."
- Professor Massimo Pigliucci (mainstream author of numerous scientific papers on evolution) has stated that "old-fashioned metaphors like genetic blueprint and genetic programme are not only woefully inadequate but positively misleading."
- Neuroscientist Romain Brette states, "The genome does not encode much except for amino acids."
- In a 2016 scientific paper, three scientists state the following: "It is now clear that the genome does not directly program the organism; the computer program metaphor has misled us...The genome does not function as a master plan or computer program for controlling the organism; the genome is the organism's servant, not its master.
- In the book Mind in Life by Evan Thompson (published by the Belknap Press of Harvard University Press) we read the following on page 180: "The plain truth is that DNA is not a program for building organisms, as several authors have shown in detail (Keller 2000, Lewontin 1993, Moss 2003)."
- Developmental biologist C. H. Waddington stated, "The DNA is not a program or sequentially accessed control over the behavior of the cell."
- Scientists Walker and Davies state this in a scientific paper: "DNA is not a blueprint for an organism; no information is actively processed by DNA alone...DNA is a passive repository for transcription of stored data into RNA, some (but by no means all) of which goes on to be translated into proteins."
- Geneticist Adam Rutherford states that "DNA is not a blueprint," a statement also made by biochemistry professor Keith Fox.
- "The genome is not a blueprint," says Kevin Mitchell, a geneticist and neuroscientist at Trinity College Dublin, noting "it doesn't encode some specific outcome."
- "DNA cannot be seen as the 'blueprint' for life," says Antony Jose, associate professor of cell biology and molecular genetics at the University of Maryland, who says, "It is at best an overlapping and potentially scrambled list of ingredients that is used differently by different cells at different times."
- Sergio Pistoi (a science writer with a PhD in molecular biology) tells us, "DNA is not a blueprint," and tells us, "We do not inherit specific instructions on how to build a cell or an organ."
- Michael Levin (director of a large biology research lab) states that "genomes are not a blueprint for anatomy," and after referring to a "deep puzzle" of how biological forms arise, he gives this example: "Scientists really don’t know what determines the intricate shape and structure of the flatworm’s head."
- Ian Stevenson M.D. stated "Genes alone - which provide instructions for the production of amino acids and proteins -- cannot explain how the proteins produced by their instructions come to have the shape they develop and, ultimately, determine the form of the organisms where they are," and noted that "biologists who have drawn attention to this important gap in our knowledge of form have not been a grouping of mediocrities (Denton, 1986; Goldschmidt, 1952; B. C. Goodwin, 1985, 1988, 1989, 1994; Gottlieb, 1992; Grasse, 1973; E. S. Russell...Sheldrake, 1981; Tauber and Sarkar, 1992; Thompson, 1917/1942)."
- Biologist B.C. Goodwin stated this in 1989: "Since genes make molecules, genetics...does not tell us how the molecules are organized into the dynamic, organized process that is the living organism."
- An article in the journal Nature states this: "The manner in which bodies and tissues take form remains 'one of the most important, and still poorly understood, questions of our time', says developmental biologist Amy Shyer, who studies morphogenesis at the Rockefeller University in New York City."
- Timothy Saunders, a developmental biologist at the National University of Singapore says, "Fundamentally, we have a poor understanding of how any internal organ forms.”
- On the web site of the well-known biologist Denis Noble, we read that "the whole idea that genes contain the recipe or the program of life is absurd, according to Noble," and that we should understand DNA "not so much as a recipe or a program, but rather as a database that is used by the tissues and organs in order to make the proteins which they need."
- A paper by Stuart A. Newman (a professor of cell biology and anatomy) discussing at length the work of scientists trying to evoke "self-organization" as an explanation for morphogenesis states that "public lectures by principals of the field contain confidently asserted, but similarly oversimplified or misleading treatments," and says that "these analogies...give the false impression that there has been more progress in understanding embryonic development than there truly has been." Referring to scientists moving from one bunk explanation of morphogenesis to another bunk explanation, the paper concludes by stating, "It would be unfortunate if we find ourselves having emerged from a period of misconceived genetic program metaphors only to land in a brave new world captivated by equally misguided ones about self-organization."
- Referring to claims there is a program for building organisms in DNA, biochemist F. M. Harold stated "reflection on the findings with morphologically aberrant mutants suggests that the metaphor of a genetic program is misleading." Referring to self-organization (a vague phrase sometimes used to try to explain morphogenesis), he says, "self-organization remains nearly as mysterious as it was a century ago, a subject in search of a paradigm."
- Writing in the leading journal Cell, biologists Marc Kirschner, John Gerhart and Tim Mitchison stated, "The genotype, however deeply we analyze it, cannot be predictive of the actual phenotype, but can only provide knowledge of the universe of possible phenotypes." That's equivalent to saying that DNA does not specify visible biological structures, but merely limits what structures an organism can have (just as a building parts list merely limits what structures can be made from the set of parts).
- At the Stack Exchange expert answers site, someone posted a question asking which parts of a genome specify how to make a cell (he wanted to write a program that would sketch out a cell based on DNA inputs). An unidentified expert stated that it is "not correct" that DNA is a blueprint that describes an organism, and that "DNA is not a blueprint because DNA does not have instructions for how to build a cell." No one contradicted this expert's claim, even though the site allows any of its experts to reply.
- A paper co-authored by a chemistry professor (Jesper Hoffmeyer) tells us this: "Ontogenetic 'information,' whether about the structure of the organism or about its behavior, does not exist as such in the genes or in the environment, but is constructed in a given developmental context, as critically emphasized, for example, by Lewotin (1982) and Oyama (1985)."
- Biologist Steven Rose has stated, "DNA is not a blueprint, and the four dimensions of life (three of space, one of time) cannot be read off from its one-dimensional strand."
- Jonathan Latham has a master's degree in Crop Genetics and a PhD in virology. In his essay “Genetics Is Giving Way to a New Science of Life,” a long essay well worth a read, Latham exposes many of the myths about DNA. Referring to "the mythologizing of DNA," he says that "DNA is not a master controller," and asks, "How is it that, if organisms are the principal objects of biological study, and the standard explanation of their origin and operation is so scientifically weak that it has to award DNA imaginary superpowers of 'expression'” and 'control' to paper over the cracks, have scientists nevertheless clung to it?"
- An interesting 2006 paper by six medical authorities and scientists tells us that "biochemistry cannot provide the spatial information needed to explain morphogenesis," that "supracellular morphogenesis is mysterious," and that "nobody seems to understand the origin of biological and cellular order," contrary to claims that such order arises from a reading of a specification in DNA.
- Keith Baverstock (with a PhD in chemical kinetics) has stated "genes are like the merchants that provide the necessary materials to build a house: they are neither the architect, nor the builder but, without them, the house cannot be built," and that "genes are neither the formal cause (the blueprint), nor the efficient cause (the builder) of the cell, nor of the organism."
- Evolutionary biologist Richard Lewontin stated, "DNA is not self-reproducing; second, it makes nothing; and third, organisms are not determined by it." Noting that "the more accurate description of the role of DNA is that it bears information that is read by the cell machinery," Lewontin lamented the "evangelical enthusiasm" of those who "fetishized DNA" and misspoke so that "DNA as information bearer is transmogrified into DNA as blueprint, as plan, as master plan, as master molecule." In another work he stated "the information in DNA sequences is insufficient to specify even a folded protein, not to speak of an entire organism." This was correct: DNA does not even specify the 3D shapes of proteins, but merely their sequence of amino acids.
- In 2022 developmental biologist Claudio D. Stern first noted, "All cells in an organism have the same genetic information yet they generate often huge complexity as they diversify in the appropriate locations at the correct time and generate form and pattern as well as an array of identities, dynamic behaviours and functions." In his next sentence he stated, "The key quest is to find the 'computer program' that contains the instructions to build an organism, and the mechanisms responsible for its evolution over longer periods." Since this was written long after the Human Genome Project had been completed, he thereby suggested that no such instruction program had yet been discovered in the genome (DNA).
- A 2024 article says, "Martínez Arias, 68, argues that the DNA sequence of an individual is not an instruction manual or a construction plan for their body...The Madrid-born biologist argues that there is nothing in the DNA molecule that explains why the heart is located on the left, why there are five fingers on the hand or why twin brothers have different fingerprints."
- Two scientists said this: "We see no valid use for definitions of the genotype and phenotype in terms of blueprints, programs, or sets of instructions, and their realizations or manifestation....The program/manifestation metaphor is factually misleading, because it suggests that the genotype uniquely determines an organism’s phenotype. However, as is well known, all it does is specify an organism’s norm of reaction to environmental conditions (Rieger et al., 1991,Lewontin, 1992)."
- A 2022 paper in the journal Science (one authored by more than ten scientists) says this: "Although the genome is often called the blueprint of an organism, it is perhaps more accurate to describe it as a parts list composed of the various genes that may or may not be used in the different cell types of a multicellular organism....The genome in and of itself does not provide an understanding of the molecular complexity of the various cell types of that organism."
- A Duke University biologist and a Cornell University biologist have confessed this: " No information about the overall architecture of these body parts is present in the cells and tissues of the parts themselves, or in each organism’s genes."
- Physics PhD Eric Heden states, "The molecular coding within DNA, rich and vast as it is, falls impossibly short of being able to supply the informational guidance needed to supervise the development and moment-by-moment cellular activities of living organisms."