The Selfish (Non-Nucleic) Gene

1976 saw the publication of a book called “The Selfish Gene” by Richard Dawkins which has recently been updated to celebrate its thirty years in publication.

I first came across it around 1979/1980 as a recommended book for one of my zoology subjects – maybe genetics or palaeontology. What I found was a book that, if you agreed with its starting point, was logical in its conclusions. But something bugged me about it: something seemed wrong but I could not put my finger on it. It was a couple of years later when I was explaining it to a non-scientist that it actually hit me. It was such a basic and obvious error that I had completely overlooked it. I can tell you I felt very stupid. So I then started to look around the scientific papers to see how many other scientists noticed the same simple fundamental error.

I am still looking.

All I have seen is gushing sycophancy for how important this book is. Needless to say that it has not enhanced my low opinion of this generation of biologists.

That would have been that if I had been re-visiting the arguments recently and discovered something really scary: that Richard Dawkins is both wrong and right.

THE BASIC ERROR

Here's the argument: your genes do not care if you survive to reproduce or if it is one of your relatives, so a gene that encourages altruism will survive and prosper and you will be expendable. It sounds reasonable, doesn't it, but there is a problem. You get half of your chromosomes (and therefore your genes) from your father and half from your mother, so there are four possible combinations:

 
X
x
X
XX
Xx
Y
XY
xY

This means that if I have a sibling, there is 1 in 4 chance of having the same combination of chromosomes, 1 in 2 chance of having just one chromosome in common and 1 in 4 chance of not having either chromosome in common. So, if I sacrifice myself for another sibling, I have the same chance (25%) of having the same combination of genes survive as not and only 50:50 chance of getting just one set of chromosomes surviving. Yet, I have 100% chance of my exact gene sequence surviving if I survive. So, a selfish gene would not lead to altruism, it would lead away from it because the odds of it surviving are always worse for another person. Once you see that the entire basis of Dawkins' book unravels. And the sad part is that it is Genetics 101.

NOW THE SCARY BIT

However, there is one situation where Dawkins' arguments are spot-on. There is something that I have in common with every single sibling – as well as my mother. I get half my nucleic genetic material from my father but everything else comes from my mother – including a lot of non-nucleic genetic material stored in your mitochondria. That is as good as 100% to me as to make no difference. In the case of my mitochondrial genes, it makes absolutely no difference if I live or one of my siblings. It would appear that mitochondrial DNA mutates at a faster rate than nucleic DNA. Nonetheless, I am still more likely to share a larger portion of mitochondrial DNA in common with a complete stranger than I am nucleic DNA with my own sibling, especially if that sibling is a different gender. In fact, I am likely to share more mitochondrial DNA in common with other mammals than I am nucleic DNA with my sister. This would explain why a fire fighter would sacrifice their life to save a complete stranger and even why someone would risk their lives to save their cat. As far as my mitochondrial DNA is concerned, I am so expendable.

Did you notice the scary thought?

When I was at university, there was a move away from the Pyramid model of life towards the Onion model. The Pyramid model was popular with the Victorians who thought of lower life at the bottom and complexity increasing up the pyramid until you got to the most highest and most evolved example of life: us. The Onion model also started with simple, single-celled marine organisms. However, it sees them as the centre of the onion because they have the greatest diversity of species, greatest population numbers and sheer size in terms of their biomass. In terms of living, they have it the easiest because their environment is so stable – so all they do is eat and reproduce. It then goes on to see the different layers of the onion as life trying to find ways to survive by adapting to more and more inhospitable areas where there is less competition to live. For example, when we left the sea, we created a whole host of problems for ourselves: dehydration, temperature change, finding our next drink of water, supporting our own body mass because the water no longer did it and so on. The Onion model sees life in terms of making more and more desperate decisions to find a niche to survive in. The Onion model unseated humankind from its position of pre-eminence and made our intelligence just another desperate attempt to survive because we were stupid enough to leave the oceans. But at least it gave us a reason for why life evolved in the way it did. If we accept the argument of the Selfish Non-Nucleic Gene, then not only am I completely irrelevant but so is the human race and mammals and probably every other group as well. This argument makes mitochondrial DNA the driving force of evolution and our Nucleic DNA just a bystander. So, why do we exist if we are so irrelevant? Maynard-Smith put it very well when he said Darwinism explains why ducks have webbed feet but it does not explain why we have ducks in the first place. And that is true for all of us. Really, why are we existing when we are so genetically irrelevant?

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