These are excerpts and elaborations from my book "The Nature of Consciousness"
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A body is made of cells.
Every single cell in the same body contains roughly the same genetic
information (barring copying mistakes). However, each cell ends up specializing
in a task, depending on where it is located: a heart cell will specialize in
heart issues and not, say, liver issues, even though the genetic information
describes both sets of issues. A muscle cell is a muscle cell, even though it
is identical to a liver cell. This is the phenomenon of "cell
differentiation", by which each cell "expresses" only some of
the genes in the genome, i.e. only some of the possible proteins are
manufactured ("synthesized"). The human body has about 265
different cell types. Differentiation seems to be
regulated by topology: depending on where a cell is, it exchanges energy (which
is information) with some cells rather than others. Neighboring cells
"self-organize". How cells develop to be what they will be within the
body is probably determined by a regulatory mechanism: instead of each cell
being "told" by the genes what to become, cells interact among
themselves; and the body is the emergent outcome of their interaction. This is
an efficient way to produce complex bodies: the genome does not need to specify
where each of the 100 trillion cells must go. The difference between humans and
chimps is caused by a mere 1.6% of the genome: it is the interactions among
cells that greatly amplify that 1.6%. Another advantage is that the body can
repair itself: if a cell is damaged, interaction among cells yields a new
configuration that makes that damage irrelevant. The price that the organism
pays is a long period of "incubation" during which the body develops
(and it is vulnerable). A puzzling feature of
genomes is that they contain far more useless junk than useful genes. The human
genome, in particular, contains about 95% junk, in between genes. Back to the beginning of the chapter "The Evolution of Life: Of Designers and Design" | Back to the index of all chapters |
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