DNA's Role with Proteins
Is it sure that the most important information of living
cells is stored in the DNA? DNA seems to be nothing more than an
inventory of useful proteins and a tool to create those proteins. Could
it be that more important operational know how of how these proteins
interact to build a living organism is actually located in the rest of
the cell? So that the rest of the cell is the most important
inheritance, whereas DNA merely takes care of the genetic variation?
DNA is the entire library of protein information for an organism. All
seven types of protein. It is true that in developmental stages of an
organism that the presence and absences of certain proteins and other
chemicals generated by proteins will influence what the DNA in a
"particular" cell will express. Hence, you can start out with one cell
and end up with a complex organism. You may have heard some of this
information with the cloning activities that have been going on
lately. All the inheritance comes from the DNA, but what parts of the DNA
expression may be dictated by the cells special characteristics developed
upon specializing. In that way the liver cells will only do "liver"
things and the kidney cells will only do "kidney" things, BUT they use the
same DNA information to operate, just a different portion of the same DNA
that pertains to their particular "job". If you can convince a cell that
it does not have a special job anymore, then you can develop the entire
organism from this cell with the right signals; this is what cloning
techniques have done!
If the genetic content of a cell were more than DNA,
it should be present in the germ cells to be passed on
to future generations. And you are right: DNA itself
is not enough. The way the DNA is folded and kept
together by proteins adds to the information carried
on the DNA. So although the DNA (in some viruses it is
RNA) is the carrier of genetic information, this
information can only be correctly interpreted
('exrpessed') if the DNA is covered and held together
by the correct proteins. This complete structure is
called the chromosomes, and these, as is generally
believed, are sufficient for all genetic information.
Modern technology in which 'empty' germ cells are
refilled with chromosomes from foreign donor germ
cells confirm this theory.
Click here to return to the Biology Archives
Update: June 2012