Selfish Gene Theory

[pineapplebunnybounce]

Sure! One thing that throws me off in trying to imagine the actual utility of the gene is his personification and metaphors comparing them to conscious agents. In what way exactly are genes "alive" in the survival machine? Should I imagine it in the way that viruses or bacterias are? I recently read an Ernst Mayr selection and he was no fan of the selfish gene theory because in his opinion natural selection could only pressure individual phenotypes, rather than the (millions? billions?) of genes within the individual. Can you expound on this process of gene selection?

Oh ok. No, genes aren't conscious. I'm not sure which specific part of the book you're referring to, but genes are alive because they still call the shots. Their job isn't done when the machine is built, they are highly regulated and respond to stimuli, except there is a time delay in the response, which is why the machine has a certain amount of autonomy to ensure survival.

To understand the selfish gene theory, you must first understand that genes are possibly immortal. They can be copied for an eternity. But machines are mortal and die off, most likely never to be replicated again. So the ultimate goal of evolution is the survival of the genes, not the survival of machines. The traditional view used to be more egocentric and view the genes as servants of the machine. The selfish gene theory flips that around.

That's why selection is ultimately gene selection and not really phenotypic selection. Because phenotypes only get passed on if the genes for it are there. If the genes aren't there, the phenotype dies off. You cannot select one without selecting the other. But because genes are more permanent in the evolutionary timescale, it is the one that is ultimately selected. You can have genes in you that is no longer expressing itself but piggybacking on the active genes. These can still pull tricks that ensure their survival without affecting phenotype. Such as being close (in terms of placement on the actual chromosome) to a very important gene. So every time the very important gene gets passed on, this useless gene gets to survive another generation of machines.

Edit: Oh and remember that the measure of fitness in evolution isn't how well you survive but how well you reproduce. So the machine is selected to propagate the genes and the genes are not selected to help the survival of the machine after the machine is past reproductive age. In fact, a theory for aging and senescence is that we have a lot of beneficial genes that turn bad after a certain age, but they get passed on because we reproduce when we're younger. So genes do not serve the machine, they only help us to help themselves.