As I have tried to point out, the success of an individual colony is not simply that it had the right genes, nor can this combination of genes be passed on directly and intact to its offspring. This excerpt expands on that idea:





Simplistic ideas of how genes ‘cause’ traits are no longer viable: life is an orderly collection of uncertainties



Perhaps the most important single fact ... is that when numerous genes contribute to a trait, the specific set of contributing variants is different for every individual. This is a many-to-many causal relationship: there are many genetic paths to a single height, blood pressure, triglyceride, or cholesterol level. Equally, a given genotype is consistent with many different trait values. Each genetic variant is a very weak ‘coin flip’ with unstable probabilities, and everyone is flipping a different set of coins. So, even if we identify the genotype of an individual, we can’t as a rule accurately predict its effects, even though this is just what ‘personalised genomic medicine’ has promised to do.



We should not be at all surprised that, just like most other traits, behaviour is not specifically predictable from genes. The massive web of probabilism makes such prediction weak at best, just as we’ve seen for physical traits.  But the reason is that the causation involved is so complex and deeply probabilistic that it is, in effect, unpredictable even if we were to try to enumerate all the contributing factors. 



Human beings don’t like things that are unexplained. We want the comfort and sense of safety that comes from predictability. ... We are made very uneasy by things that are only probabilistic unless, as in coin-flipping, we can sense what’s going on. When we can’t see it, and causation is many-to-many, that is far too much for our minds to deal with easily. Yet that seems to be the reality of the world.



Things genes can’t do

by Kenneth Weiss and Anne Buchanan



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