Genome complexity: error correction (Introduction)

by David Turell , Thursday, June 03, 2021, 15:52 (1050 days ago) @ David Turell

Each genome has a system:

https://iai.tv/articles/the-gene-illusion-auid-1813?_auid=2020

"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. (my bold)

***

"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."

Comment: The error control system had to be present when DNA appeared or we would not be here. The first paragraphs show this. The last comments were directed at criticisms of Dawkins 'selfish gene' theory I've not quoted.