Genes, Brains, and Human Potential The Science and Ideology of Intelligence

REAL GENES, REAL INTELLIGENCE 131

that make us physically unwell and prone to viral infections and chronic
diseases, just as feeling particularly relaxed and peaceful can turn off
those genes and activate others that help us heal and fi ght infections. Th e
emerging fi eld of human social genomics is demonstrating that social
conditions, especially our subjective perceptions thereof can radically
change our gene expression states.”^27
All this indicates how the model of the cell and the organism as a
machine, with form and variation written in the genes, is obsolete. In-
stead, adaptability in changing environments (as opposed to the static
circumstances of the model) has required integration of bottom-up and
top- down pro cesses across numerous levels. Th ey are self- organized,
dynamical systems with emergent properties, in which genes are servants,
not masters. Th ey allow cells to have dramatically diff er ent forms and
functions through regulations beyond the genes. And they transform
development from a passive executor of ge ne tic instructions into creative
adaptabilities.
We will be visiting all those diff er ent levels in the rest of the book.
For the remainder of this chapter, let us look at some immediate mani-
festations of those dynamics.

Form and Variation Are Unpredictable

Even a brief survey of complex forms and functions reveals unpredictable

relationships between variation in genes and variation in the phenotype.

In complex, adaptable traits there is no direct mapping from genes to

phenotype. And that, in changing environments, is for the best of evo-

lutionary reasons. Instead we get a dynamical system that is far more

adaptable to changing environments.

Most Ge ne tic Variation Is Irrelevant
As with choosing which font you type with, most gene mutations and
subsequent protein variations are, except in rare circumstances, irrele-
vant to function. Most traits crucial for survival are buff ered against such
ge ne tic variations; they are canalized in development, as described in
chapter  5, or are subsumed into developmental plasticity. With the

This content downloaded from 139.184.14.159 on Tue, 17 Oct 2017 13:52:50 UTC