Interview with Dr. Rick
Meilan, Molecular Tree Physiologist at Purdue University
The Story on GMOs
GMO stands for Genetically Modified Organism.
Let’s break it down word by word. Genetically refers
to genes. Genes are made up of DNA, which is a set
of instructions for how cells grow and develop.
Second is Modified. This implies that some change or
tweak has been made. Lastly, we have the word
Organism. When it comes to GMOs, many people only
think of crops. Yet an ‘organism’ isn’t just a
plant; it refers to all living things, including
bacteria and fungi.
With that in mind, GMOs are living beings that
have had their genetic code changed in some way.
While conventional breeding, which has been going on
for centuries, involves mixing all of the genes from
two different sources, producing a GMO is much more
targeted. Rather than crossing two plants out in the
field, they insert a gene or two into individual
cells in a lab. Yet, as mentioned earlier, GM
technology can also be used on microorganisms. For
example, bacteria have been genetically modified to
produce medicines that can cure diseases or vaccines
that prevent them. A commonly used medicine that
comes from a genetically modified source is insulin,
which is used to treat diabetes, but there are many
others.
The process to create a GMO starts very small. A
scientist causes a gene to be inserted into the DNA
in the nucleus of a single cell. The DNA being used
for the modification is so small that it can’t be
seen, even under the most powerful microscope.
Despite how tiny a cell is, there is a massive
amount of DNA all packaged into its one little
nucleus. To give some idea of just how much DNA is
packed into that small space, if you were to take
all the DNA of one single corn cell out of the
nucleus and line it up end-to-end, it would be about
six feet long! Into this enormous amount of DNA, a
very small piece is inserted. A vast majority of the
organism’s genetic code remains completely unchanged
by the process.
Once this single cell has been modified, the
scientist will treat it with naturally occurring
plant hormones to stimulate growth and development.
This one cell will start to divide (which is the
natural growth process for any organism) and the
resulting cells begin to take on specialized
functions, until they become a whole plant. Because
this new plant was ultimately derived from a single
cell with the inserted gene, all of the cells in the
regenerated plant contain that new gene.