To: North American Fruit Explorers <nafex@lists.ibiblio.org>
Subject: Re: [NAFEX] GMO and Breeding
Date: Fri, 30 Dec 2005 17:47:05 -0800
Most people think of genes as discreet units. They are not. Each
gene is composed of many subunits in a particular order. When that
gene is read by the enzymes that transcribe it into it's intended
product, where the enzyme starts and finishes on the gene are important
to what comes out. Think of a car riding along a string of beads, with
the product coming out of the car as it goes along. If the string is
damaged, the car hits a roadblock and either can't go on, or jumps the
damage and produces something with a section missing. The result is a
product that may or may not resemble the original product enough to
function. To add to this, many genes are in series and need to be
read in order to produce the final result correctly. Move a gene and
you may alter the organism's ability to produce something it needs, or
worse yet, cause it to produce something it wouldn't ordinarily make.
Mutation breeding usually makes use of this by altering a single gene,
by changing a single bead on the gene's "string" but without changing
much else. The gene produces a slightly altered product, which, with
luck, is useful to the organism. More importantly, the altered gene is
still in the same place in the series, so the odds of producing a
really altered product are small. But mutations generally don't alter
anything else in the organism, so the plant or animal stays pretty much
in balance, genetically speaking.
The difficulty with Genetic Modification is that it doesn't insert
absolute distinct genes, and they don't simply replace something very
similar on an established pathway. There are always bits of extra
genetic material attached, which are out of place on the chromosome,
and are apt to be "read" and produce something entirely foreign to the
organism. Most often, the result is probably a protein of some sort
that the plant doesn't recognize, so nothing is done with it, and it
accumulates in the cell.
This means that there is a strong likelyhood that GM plants will
contain proteins of sorts that they have never contained before, and
which the consumer's metabolism doesn't recognize. What happens when a
foreign, unfamiliar, protein is introduced into the body? One reaction
is that the body treats it as an invader and reacts to it, forming
antibodies. Repeated exposure to the protein may cause the body to
react strongly to it. What is another term for this kind of reaction?
Allergy.
Question. What condition is increasing in America faster than almost
any other disease? Asthma and allergies.
I'm not saying that GM foods are the cause, but the coincidental rise
of GM foods with asthma seems worth looking into.
This is just one small reason why use of GM technology needs a lot
more study, over a longer period of time.