Junk DNA
Over 95 percent of DNA has largely unknown function
By Jaan Suurkula M.D.

Presently, only the function of a few percent of the DNA is known, the rest has been
believed to be useless garbage, commonly called "Junk DNA" by molecular biologists.
Increasing evidence is now indicating that this DNA is not "junk" at all. Especially, it has been
found to have various regulatory roles. This means that this so-called "non-coding DNA"
influences the behavior of the genes, the "coding DNA", in important ways.
However, the knowledge is still very incomplete about this DNA. And there is little
knowledge about the relationship between non-coding DNA and the DNA of genes.
Without this knowledge it is completely impossible to foresee and control the effect of
artificial insertion of foreign genes.

This is a very important reason why genetic engineering is unsuitable for commercial
application. It is still at a stage of early experimentation with very incomplete understanding
about its consequences. According to the ethical standards of sound science, the products
of such experimentation should be strictly contained in laboratories, especially as released
DNA may spread indefinitely in an uncontrollable way.

Presently, only the function of a few percent of the DNA is known, the rest has been
believed to be "junk". The most exhaustive knowledge is about the genes responsible for
the bodily structures, the structural genes, which are the simplest part of the system. But
the knowledge about the most important part of this system, the regulator genes, is
incomplete. The genetic code language of these genes is only partially known.
More than 95 percent of all DNA was called "Junk DNA" by molecular biologists, because
they were unable to ascribe any function to it. They assumed that it was just "molecular
garbage". If it were "junk", the sequence of the "syllables", i.e. the nucleotides in DNA
should be completely random.

However it has been found that the sequence of the syllables is not random at all and has a
striking resemblance with the structure of human language (ref. Flam, F. "Hints of a
language in junk DNA", Science 266:1320, 1994, see quote below). Therefore, scientists now
generally believe that this DNA must contain some kind of coded information. But the code
and its function is yet completely unknown.

It has been reported that the sequences of this unknown DNA are inherited and that some
repetitive patterns in it seem to be associated with increased risk for cancer. Also, the DNA
has been found to mutate rapidly for example in response to cancer. It has been speculated
that this DNA may contribute to the regulation of cellular processes. Haig H. Kazazian, Jr.,
chairman of genetics at the University of Pennsylvania has recently found reasons to suspect
they may be a key force for the development of new species during evolution. He thinks this
DNA may be essential for increasing the plasticity of the hereditary substance.
Published at this website in May 1997.