DNA: not a fortune-teller

I’ve made this argument before (see here and here and here) and so it is gratifying (as always) to see someone else make the same argument albeit with a different emphasis.

A SciAm blog post by Kevin Mitchell (Is Our Future Really Written in Our Genes?) attacks the fallacy of genetic determinism by pointing out that our DNA does not contain nearly enough information to specify all the neural connections that condition and define brain function–that is to say, our personalities and our abilities. Random effects at the molecular level–which are a fundamental property of matter–mean that noise meaningfully impacts the outcome of brain development. Gene variants and permutations of gene assemblages certainly influence the probabilities of certain outcomes, but they can never determine it. Not at the level of the individual. Give his post a read.

The messiness of biology: A super-close-up reconstructed view of the synapses on a dendrite, with the synaptic vesicles (little white dots that store neurotransmitters) also visible. From Can we build a complete wiring diagram of the human brain?

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