Epigenetics crosses multiple generations. It may play a significant
role in what makes a chicken a chicken. The chicken is more than its
DNA. The chicken may in significant part be the egg, and the
mother's egg, etc.
http://www.ideacenter.org/contentmgr/showdetails.php/id/821
http://tinyurl.com/re7bva
"Practicing good science led researchers to a novel discovery in a
weed (weedy cress, Arabidopsis thaliana) (see Lolle, S.J., Victor,
J.L., Young, J.M., and Pruitt, R.E., "Genome-wide non-mendelian
inheritance of extra-genomic information in Arabidopsis," Nature 434
(24 March 2005): 505-509.). What researchers found was that the weeds
were inheriting their grandparents' normal DNA which did not exist in
their parents' mutated DNA (see this picture [from article in
NewScientist.com] for a great schematic image of this) - according to
Mendelian genetics, that's supposed to be impossible! Offspring are
not supposed to be able to have DNA that does not exist in their
parents, unless it is a mutation (which researchers ruled out in this
case). By following the evidence where it led, these researchers may
have stumbled across a small piece in the complex developmental
information puzzle that goes well beyond DNA. Rather than throwing
out evidence that doesn't match the neo-Darwinian paradigm (in this
case, Mendelian genetic inheritance), researchers practice good
science and can make significant scientific discoveries. Some of the
researchers speculate that there may be RNA playing a role in storing
the "normal" genetic information for safe-keeping when mutations
occur. Regardless of what the error-correcting mechanism turns out to
be (which may show promise for helping cure various genetic
diseases), it's clear DNA is not the definitive developmental
information storer."
"A recent finding, published in the journal Cell (Bernstein, B. E.,
Kamal, M. et al. Genomic maps and comparative analysis of histone
modifications in human and mouse. Cell 120, 169-181 (2005)), based on
studies of histones in mice and humans, causes a problem for the
rational behind relating different organisms through genetic
comparisons. With the advent of genetic mapping technology, supposed
phylogentic relationships have often been constructed based on
comparisons of various organism's DNA sequences. Yet, this new
finding shows that DNA may not be as reliable an indicator for
evolutionary ancestral relations as previously thought. What was
found was that histone modifications are highly conserved between
mice and humans, even when the DNA sequences in these same histone
areas are not. In fact, as noted in a Nature Reviews Genetics summary
(EPIGENITICS: It's not all in the DNA), author Tanita Casci commented
that, "[w]hat was striking, however, was that the DNA sequence of
functionally conserved sequences, as inferred from histone profiling,
did not coincide with higher levels of sequence conservation,
implying that comparative genomics is no reliable way of detecting
stretches of DNA with conserved epigenetic marks." It turns out
histones play a significant role as a genetic regulator rather than
being passive molecules simply "holding" DNA. Interested readers may
find a previous summary article on this interesting (see Li, E.
Chromatin modification and epigenetic reprogramming in mammalian
development. Nature Rev. Genet. 3, 662-673 (2002))."
Interestingly, the above site is apparently a pro-design anti-Darwin
site. There appears to be a failure to realize that the fact
evolution is far more complex than Darwin realized does not discount
but rather supports the fact evolution exists.
The existence of evolution seems to me to be independent of the
question of creationism. The fact evolution exists, however complex,
neither supports nor discounts the possibility it was created. The
main concern for creationists then should be *when* the creation
occurred. This is the essence of the chicken and the egg problem
when considered from a creationist viewpoint.
Best regards,
Horace Heffner
http://www.mtaonline.net/~hheffner/
