When people talk about the advantages of sexual reproduction, one of the (if not the) primary responses is to create genetic diversity.
But what if the opposite is true? What if sexual reproduction evolved initially as...and primarily remains... a mechanism to prevent excessive genetic drift due to lateral gene transfer and mutation? (In that order)
In recent years we’ve learned that it’s the virus that’s the heavy hitter for creating genetic diversity on the bacterial side rather than mutation. In retrospect that’s kind of obvious since mutation generally flips bits while viruses deliver entire subroutines from elsewhere...but that does also mean everything we derived from that concept also bears a bit of rethinking. Why do they slowly stop being a heavy hitter with us eukaryotes? What makes us special?
That’s where sexual reproduction comes in. I invite you to stop a moment to think about what actually happens during the process and think of all of that DNA as data and code. What’s the net effect of the process of making backups of something and then copying all the files back and forth every now and then when compared to just letting files become corrupt?
See? You end up with LESS variation not more. That’s why we keep having to load files off of disk, they keep mutating in memory. But if we mod a file and it still works then people play it. If it gets popular then suddenly it’s everywhere. If it’s buggy and keeps crashing all the time then the adherents slowly fade away.
Things really come into focus with us metazoans. Having more than one cell carries with it a whole new set of complications. We’re constantly mutating and changing and the virus/chromosome dance is still happening. Do you think all the cells in your brain are genetically identical?
They’re not. Each one is a unique and special snowflake with thousands of genetic variances. The same goes for all the cells in your body. Sure, we hear about it when one of them decides this ‘cooperation’ thing is for nerds and gives us cancer. (And every now and then one of those little experiments works too and becomes a whole new thing like Cloney, the tiniest puppy)...but in general we don’t think too much about the fact that every cell in our body is blazing its own trail.
That’s why our germ cells are so precious. They’re what keeps the species going, that’s what keeps us compatible. Having incompatible reproductive bits just mirrors the fact that we also have incompatible DNA.
And that’s why I wonder if perhaps I learned everything backwards, and perhaps sex is there to keep us the same.
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