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The gene illusion

Biological relativity and the Emperor's New Genes

21 06 07.The gene illusion

Once we debunk our current dogmatic understanding of how genes and living systems work, we will fundamentally change the view of ourselves and our place in nature, writes Denis Noble.

 

A debate organised by the IAI at HowTheLightGetsIn festival five years ago used the title “The Emperor’s New Genes” as a play on the old story about the tailors who made new clothes of the finest silk for the Emperor in which to display his prowess. Eventually, the silk they used was so fine that it was indeed a transparent “see-through” gown. It took a small boy in the crowd to shout out “the Emperor has no clothes!”

The central point of my contribution to the debate was a statement I had made in a new book called Dance to the Tune of Life: Biological Relativity, where I wrote “there is no gene for anything!” Not surprisingly, this shocked some in the audience brought up on Richard Dawkins’ book The Selfish Gene, where he states that “they [genes] made us body and mind.”

Dawkins also writes of DNA that it faithfully replicates like a crystal: “This is how crystals are formed”. This is the basis of his distinction between “immortal” genes as the “replicators” and the “mortal” body that conveys them to the next generation. One way of explaining why there are no genes for anything is to show that those statements are incorrect: they are the illusions of modern evolutionary biology.

 

How DNA replicates

 

The idea that DNA copies itself in the way in which a crystal grows originates with the quantum mechanics pioneer Erwin Schrödinger in his 1942 book What is Life?  It seemed so plausible that the idea was developed further when Watson and Crick discovered the Double Helix. This led to Crick’s famous Central Dogma of molecular biology, and to the idea of one-way causation from genes to proteins to cells, tissues, organs, all the way up to the whole body.

Crystals grow by each molecule inserting itself into the lattice structure formed by the existing crystal. This chemical process is automatic. Many schoolchildren will have grown crystals in their chemistry classes and see it all happen.

One way of explaining why there are no genes for anything is to show that those statements are incorrect: they are the illusions of modern evolutionary biology.

But, in the body, DNA does not exist as a crystal. It cannot, therefore, rely on providing a three-dimensional template into which other DNA molecules can automatically insert themselves.  Instead, the double helix unwinds to enable proteins that can string nucleotides together to form a new thread by using a simple chemical fact. The nucleotides like to associate with each other in pairs. A likes to join with T, C with G. That is how the double helix sticks together: one thread is then a mirror image of the other. The copying proteins use that preference for association between complementary nucleotides to create a new thread from one that is being unwound from the double helix.

 

DNA does not self-replicate like a crystal

 

If that process was accurate, DNA could still be replicated almost automatically provided those copying proteins are present. Indeed, some small RNA viruses ensure their ability to replicate inside a living cell by carrying those proteins in the virus itself.

But there is a snag, and it is a serious one. Errors occur during the copying process. The chemical specificity of the bonding of the complementary nucleotides is not perfect. Roughly speaking, an error occurs every 10,000 nucleotide bases. That may not seem very much. If this article, which is around 10,000 letters long, contained just a single typo, you would almost certainly still understand it.

Now, the genome in your cells is not just 10,000 base pairs, It is around 3,000,000,000  (3 billion!) base pairs.  At one error in 10,000, that means 300,000 errors. No organism could survive replication errors of that frequency. The genome would become badly degraded in just a few cell divisions.

Instead, an even larger system of proteins come along with cut and paste abilities to clean up after the replication process. That system – the cell’s proof-correcting system – systematically looks for any mismatch, cuts the thread when it finds one, and pastes in the correct nucleotide. Amazing, but true. The outcome is that the complete 3 billion long genome gets replicated at each cell division with often no errors, or just one or two.

That is one reason why DNA cannot function outside a living cell. The replicator, DNA, is therefore not separate from the vehicle, the complete cell because that proof-correcting process only occurs in living cells.

The distinction between DNA as a replicator and the cell as its vehicle is therefore also an illusion. They necessarily live or die together. That disposes of Selfish Gene theory in evolution since genes are not “sealed off from the outside world”. The same process by which those proof-correcting proteins can cut and paste DNA is precisely what enables genes to be influenced by the organism and its environment. That fact is also illustrated by two more illusions: the Weismann Barrier and the Central Dogma.

Denis Noble, Rupert Sheldrake and Anne Bowcock look beyond the genome.

 

The illusion of the Weismann Barrier

 

Although many modern evolutionary biologists call themselves neo-Darwinists, I doubt whether Charles Darwin would have agreed with this misuse of his name. He did not think that natural selection was the only process of evolutionary change. He was also convinced that organisms could pass on at least some of their acquired characteristics to their descendants. In organisms like us with a separate germ-line – the cells that eventually become eggs and sperm – he had to suppose that some features of the body get passed on to the germ-line. In 1868, nine years after his magnum opus, The Origin of Species, he published his theory of gemmules, which he supposed were tiny particles moving through the body.

The problem with this theory is that no-one could see them with 19th-century microscopes. Of course, not everything that can form part of a valid scientific theory has to be visible for it to be correct. We know that electromagnetic waves exist but we can’t see the electromagnetic field itself. We know that the field exists because of its effects.

Darwin did not think that natural selection was the only process of evolutionary change.

Nevertheless, the difficulty in detecting his postulated gemmules was an embarrassment for Darwin. The later geneticist, August Weismann, therefore removed this idea from Darwin’s theories, and so it became neo-Darwinism, eventually documented in detail in a book, Evolution: The Modern Synthesis, by Julian Huxley in 1942, the same year as Schrödinger’s What is Life? lectures introduced his genetic crystal idea.

To formulate his idea, Weismann invented what became known as the Weismann Barrier, isolating the germ-line from the rest of the body.  This is what Dawkins refers to when he writes that genes are “sealed off from the outside world.”

That idea is also an illusion. We now know that all cells can extrude very tiny vesicles that carry controlling RNAs and other molecules, including DNAs, to other parts of the body. There is no Weismann Barrier because those vesicles, and even the free molecules themselves, can pass to and be incorporated into the cells of the germ-line. We can even visualise these vesicles with modern microscopy using a clever technique to mark chemicals with fluorescent chemicals. The vesicles can therefore be visualised with light microscopes. We know for certain that they contain RNAs and DNAs.

 

One-way causation is replaced by multi-level causation

 

We must therefore move away from the Central Dogma and its one-way causation, what Dawkins refers to as  “ancient replicators manipulating it by remote control”.  

Living systems are organised at many nesting levels, from molecules to cells to organs and the whole organism. Each level influences the processes occurring at molecular levels. In my book Dance to the Tune of Life: Biological Relativity I give the full details of this multi-level causation view, which is precisely the concept of Biological Relativity.

You experience multi-level causation in everyday life. If you train hard as an athlete you will increase the RNAs that enable your muscles to grow more protein and so become stronger. Many other molecular changes will follow in the wake of your lifestyle decision.

That fact fundamentally changes our view of ourselves and our place in nature since it restores to us and other organisms the sense of control and agency. The levels of causation mesh with each other, so that higher-level processes, such as our mental states and lifestyles, necessarily influence the processes at a molecular level that control our genes.

 


 

Note: This essay is based on three publications:

Noble, D, 2016. Dance to the Tune of Life: Biological Relativity. CUP

Noble, R & Noble, D. 2020. The physiology of agency: Can Reasons and Values Influence Action: How Might Intentional Agency Work Physiologically? Journal for General Philosophy of Science. https://doi.org/10.1007/s10838-020-09525-3

Noble, D. 2021. The Illusions of the Modern Synthesis. Biosemiotics. https://doi.org/10.1007/s12304-021-09405-3

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