Saturday, March 15, 2014

Knee deep in the fetid pools of evolution

I am, as I may have told you before, an evolutionary biologist at heart. And one of the things I love about evolution is how messy, random and complicated it is. Evolutionary outcomes aren't just survival of the fittest, but also reproduction of the luckiest and replication of the not overly deleterious. Natural selection often doesn't get its way and the optimal trait often doesn't exist or can't quite win out. Evolution is a box of dirty tooth-marked mismatched Legos with no instructions all in clumps from previous projects, and that is how I like my Legos

So I always enjoy talking with colleagues who really think about evolution in depth, not as a nice neat optimization process (which it isn't) or a collection of family tree (which it can be, but this misses the forest) but rather as the beautiful mucky anarchic tangled mess of genes, lineages, mutations and highly fallible biology that it is. Sure, there is a lot of phylogeny in there, and a bunch of natural selection, which to an extent can optimize things, but it is like optimizing the design of a boat when all you have to work with is coconut husks, maple syrup and a swarm of fire ants. It isn't so much optimization with constraints as a bowl of constraints with optimized sprinkles on top. To really capture the beauty of it you have to do away with the basically creationist notion that organisms are perfect for their niches and the anarchic view that biology follows the rules we write in text books. Organisms only breed with members of their own species, except when they don't, and clones are genetically identical to each other, unless you look closely.  Only changes to DNA are heritable, except those non-DNA heritable traits. Rules, broadly defined, do not apply to fungi. The dissertation that was defended from me this week showed that in real wild populations, genetic drift is sufficient to speed aging and shorten lifespan. These populations aren't short lived because there is something optimal about it, but rather because drift isn't letting selection have its own way. I'm oversimplifying, and you'll have to wait for the details to come out, but it is a wonderful example of evolution in its slip-shod Rube Goldberg glory.

I'd like spend more time with colleagues who think deeply about the gorgeous multi-layered sub-optimality of evolution. That's where the fun is.

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