Ask A Scientist© Molecular Biology Archive

name        Lance
status      other
age         15

Question -  Why do lifeforms on Earth have double helix
shaped DNA? Why not Triple helix or corkscrew shaped DNA?

This is an extremely deep question.  It could be answered in a number of
different ways.  Any of which would take considerable time if done
thoroughly.  We scientists are still debating what the original genetic
molecule was on earth.  From a perspective of energy, and conserving energy,
we know that stable molecules do not evolve from arrangements that use
energy the wrong way...much like friendships that take a lot of effort will
be less likely to endure.  In the same respect our knowledge of the double
helix verses a triple helix is that, with the elements involved, the double
helix takes the least effort to remain stable.
Peter Faletra
pf
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