Re: Does DNA update itself as a human grows up?

The simple answer to your question is no - the DNA of a newborn baby will 
be the same as when the person is fully grown.  Now for the complicated 
answer:  The base sequence of our DNA (i.e. the sequence of the A,T,C,and 
Gs) does not normally change as we grow older, we die with the same DNA we 
were born with.  However, as we age, our DNA may become damaged through 
environmental influences and in some cases may not be repaired properly 
(this, by the way, is one hypothesis of how we age).  In addition, as our 
cells replicate there may occur misreplication of various bases in our DNA. 
 Usually these changes (mutations) do not have any adverse affects and go 
completely unnoticed, though if mutations occur in certain genes, cancer 
can occur.  In any event, unless mutations occur in gametic cells (eggs or 
sperm), they are not passed to the next generation.  There are other 
changes associated with DNA as we age.  Normal DNA is tightly coiled into 
chromosomes.  These chromosomes have ends of genetic material on them 
called telomeres that as we age, decrease in size.  In addition, there are 
other modifications associated with DNA.  Much of our DNA is methylated - a 
methyl group is attached to the cytosine residues in our DNA.  There is 
evidence that the pattern of methylation changes as we age.  Still, single 
base mutations, changes in telomere length, and methylation differences are 
minor.
   Memory storage in DNA is an old debate.  It is almost certain that 
memories are not stored in our genes.  At one time, it was thought that the 
life experiences of an animal are passed on to its offspring.  The great 
scientist Jean Baptiste de Lamarck believed that evolution was the result 
of acquired characteristics accumulated over many generations.  Thus 
today's giraffe has a long neck because its forefathers strained their 
necks reaching for food high in the trees.  This was a view commonly held 
for centuries.  The idea that our memories are stored in our DNA is a 
Lamarckian idea.  While there are anecdotal stories and off-handed 
suggestions of tribal memories there is no concrete evidence for such 
beliefs.  Some people have argued that proto-myths (i.e. myths common to 
many different cultures, like the flood myth) are proof of genetic memory. 
 However, the renowned mythologist Joseph Campbell correctly suggested that 
these myths represent the commonality of the human experience.  Still, 
people have tried to prove that memories are contained in our genetic 
makeup.  In the 1960s and 1970s, various scientists studied a phenomenon 
called transfer of learning.  They would teach a flatworm to travel in a 
certain direction in a maze, grind it up, feed it to other flatworms and 
see if these flatworms could be trained quicker.  Much to their surprise, 
they found very significant improvement in the cannibal worms.  It turned 
out they just didn't clean their mazes well enough and the second worms 
were following a scent trail left by the first group of worms.
     One type of memory that must be genetic is instinctive memory.  
Instincts are not really memories - if we define a memory as something 
learned and stored for later retrieval - they are hardwired behaviors.  
Still, the hardwiring is controlled by our genes and is passed on from 
generation to generation.