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Lysenko were often used to discourage serious study of any role of
development and its plasticity with the environment as a legitimate force
in evolution (Richards 2006).
The epigenetic system has also been compared with cultural or
learned information (cultural toolbox) that itself evolves over genera-
tions (Bronowski 1974; Ginsberg and Jablonka 2009). This concept is
often dismissed and considered to have no consequences for biological
evolution because of its strong connection with Lamarckian ideas. The
toolboxes of culture exist as a feedback loopmechanism that would favor
inherited ability to acquire (learn) and maintain them in human popu-
lations. The extant human population could share essentially the same
DNA sequence and epigenetic status with prehistoric ancestors, but
could easily outcompete them in an all-out survival and reproduction
competition. That advantage would rapidly disappear if either the
toolboxes themselves or the ability and/or opportunity to learn was
lost or impaired. The concept of a genetic learning mechanism has not
been readily adopted in modern genetic thought because of its connec-
tion with Lamarckian views of learned or acquired traits.
However, evidence today clearly points to the entire epigenetics
system as acting in such a malleable learning and memory information
loop. By this loop, specialized speci
city
in response to developmental and environmental signals. Then,
they remember how to be speci
c cell types learn their speci
c and reproduce their own kind, by
mitosis, even when the initiating signal is long gone. The loop can form
because the epigenetic machinery (DNA methylase, histone deacety-
lase, etc.) is encoded in the DNA. Therefore, the epigenetic machinery
may control the activation or suppression of expression of DNA
sequences that encode the machinery itself. Likewise, the loop is
completed because altering the DNA sequences that encode the epi-
genetic machinery may affect the reading of the template. The system is
subject to natural selection through mutation and evolves to alter and
further stabilize perception, transduction, and outcome modes of the
loops that control phenotype (Jablonka and Lamb 2002). This is in
essence the same as the important concept of genetic assimilation. Just
as cultures do not need to return to the Stone Age to advance de novo ,
complex organisms do not need to return to single cells and advance
de novo .
Waddington
s original use of epigenetics captured all of these more
complex issues that are embedded in the core idea that epigenetics is a
template system (including the cellular toolbox/machinery) that guides
reading or interpretation of the DNA sequence. One DNA sequence
could tell many stories depending on the template, its use, and its
'
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