The Corpus Callosum

This is a follow-up to href="http://scienceblogs.com/corpuscallosum/2006/07/transgenic_drug_controversy.php">the
post from a couple of days ago.  It might not make a
lot of sense unless you have read that post, or are otherwise familiar
with the issues regarding genetically-modified crops.

In general, there are valid concerns about genetically-modified crops.
 However, it is important to think clearly about the issues
involved.  Concerns about the technology that arise from a
generalization,  may or may not
apply to a specific implementation of the technology.  In
order to understand the issues regarding transgenic rice that is used
to produce Lactiva and Lysomin, it is necessary to distinguish between
the general objections to the use of transgenic crops, and the specific
issues that arise with this particular crop.


To use an analogy: there are serious concerns about commercial use of
radioactive material, but we would not apply the same standards to
nuclear power plants as we do to the tiny bit of href="http://www.uic.com.au/nip35.htm">americium
in a smoke detector.  Thus, general concerns about genetically
modified organisms cannot automatically be applied to the question of
safety of rice that makes human milk proteins.  

And, like the matter of nuclear power, the term “genetically-modified”
has become, well, radioactive.  

In fact, in the 1980′s the public sentiment about nuclear power was so
strongly negative, that it was difficult to get people to think clearly
about it.  That was the period of time in which the technology
for magnetic resonance imaging (MRI) was being developed.  But
MRI originally was not called MRI.  It was called “nuclear
magnetic resonance imaging.”    The technique of href="http://www.pslc.ws/mactest/nmr.htm">nuclear magnetic
resonance spectroscopy was already well-known in
chemistry labs around the world.  The same technology was
adapted to make MRI possible.  Despite the”nuclear” name, it
has nothing to do with radioactivity.  MRI scans to do not
expose the patient to radioactivity.  But the connotation of
the word “nuclear” was so strongly negative, you simply could not tell
patients that they were going to get a nuclear magnetic resonance scan,
and expect them to believe that they were not getting into something
dangerous. So the name was changed, simply to avoid misunderstanding.
 

Getting back to the matter of genetically modified rice crops: I cannot
think of a plausible scenario that I find medically or
ecologically worrisome, with respect to this particular kind of genetic
engineering. 

That is entirely different than the better-known case of crops that are
modified to produce Bt
toxin
.  Bt toxins are a group of chemicals that are
produced by a bacterium, Bacillus thuringiensis.
 They are toxic to insects, but safe for humans.
 Organic farmers use preparation of the bacteria to kill
insect larvae.  

It is possible to take the genes for the toxins from bacteria, and
splice them into the DNA of a crop plant.  Then the crop
plants produce the toxin themselves.  This makes it possible
for the crops to be grown without applying pesticide externally.

There are advantages to that, plus some disadvantages.
 Advantages include reduced need for externally-applied
pesticides, and (potentially) cost savings and greater crop production.
 Disadvantages include the possibility of increased
invasiveness of modified organisms, development of resistance, and
cross-contamination of genetic material.  That is, the
modified genes could potentially show up in other crops, or other
organisms.  

The term resistance in the above paragraph refers
to the possibility that the insects that are supposed to be killed by
the toxin could evolve to the point where the toxin no longer kills
them.  I won’t belabor that point, on the assumption that the
potential seriousness of the problem is fairly obvious.

Now, turning from that, and getting back to the specific questions that
might arise concerning rice that has been modified with human genes to
produce Lactiva and Lysomin, let’s look at the potential problems, and
see if there are any specific reasons to worry.

What about invasiveness?  Would the presence of human mild
proteins confer some kind of selective advantage to rice, making it
invasive?  Almost certainly not.  If anything, it
would most likely be less invasive.  It would be wasting
resources by producing a material that does not help it in any way.

What about gene transfer?  Could the genes somehow make their
way into some other kind of organism?  Yes, they could, but it
is hard to see how that could be worrisome.  

What about resistance?  That one is a bit harder to dismiss.
 Yes, lactoferrin does have antimicrobial properties, and it
is
conceivable that having more of it out in the environment could lead to
the evolution of resistance in various microorganisms.  In
order to know if that is a real risk, it would be necessary to know the
mechanism by which lactoferrin inhibits the growth of bacteria and
fungi.  Some antimicrobial mechanisms are susceptible to
resistance, while others are not.

Furthermore, it is necessary to determine which organisms might develop
resistance, and see if any of those organisms could pose a threat, if
they were to develop resistance.  There probably are not any
microorganisms that grow on rice, that also pose a threat to humans,
but I can’t claim to be certain about that.

Given that it is a new technology, it might make sense to do some
studies to see if it is possible to breed resistance in various kinds
of bacteria.  Someone who knows more than I about agricultural
science would have to figure out if any bacteria that are found in and
around crops could potentially pose a threat, if they were to develop
such resistance. This is not the same, though, as the well-known risks
posed by agricultural
use of antibiotics
.

Personally, I doubt that there is a potential problem there.

Having said that, I do have to acknowledge that there is an economic
risk to the cultivation of genetically-modified rice.  As
mentioned in the href="http://www.nytimes.com/aponline/technology/AP-Transgenic-Diarrhea-Drug.html/partner/rssnyt">AP
article:

Many U.S. opponents, including conventional rice
farmers,
fear genetically engineered rice will inadvertently mix with their
crops and cause them economic harm.

”It’s not even just real contamination,” said Rebecca Spector of the
Center for Food Safety, which opposes biotechnology in agriculture.
”It’s also the threat of the contamination that could cause farmers to
lose their markets.”

Rice interests in California drove Ventria’s experimental work out of
the state in 2004, after Japanese customers said they wouldn’t buy the
rice if Ventria were allowed to set up shop.

Ms. Spector’s position on the Ventria rice is explained in href="http://www.centerforfoodsafety.org/page246.cfm">this
press release, from the Center for Food Safety (CFS).
 There is a little more information on the topic in this
article: href="http://www.truthabouttrade.org/article.asp?id=4182">What’s
So Scary About Rice?
, originally published in
Business Week.  There is no mention of a specific safety
concern.  In general, I welcome the involvement of advocacy
groups such as CFS.  They can force a debate on topics that
really ought to be examined.  On the other hand, it is
important to debate issues based upon specific concerns.  It
makes no more sense to categorically oppose all applications of
biotechnology, that it does to oppose all applications of
radioactivity.   That is my main point.

One thing, though, that I just can’t let go by.  The news
article I cited, href="http://www.washingtonpost.com/wp-dyn/content/article/2006/07/14/AR2006071400747.html">Uproar
in Peru Over Transgenic Drug, has a misleading title.
 First, the product is not a drug, per se;
it is a therapeutic food.  Second, the product itself is not
transgenic.  In fact, it contains no genes at all.
 Rather, it is a product that is made by transgenic rice.
 Perhaps it is picking nits to complain about this, but
sometimes it is important to be really clear about the terminology, in
order to think clearly about the subject.

Comments

  1. #1 Aaron Gunter
    November 17, 2006

    The piggyBac transposon used to genetically modify pink bollworm was originally discovered by its ability to transpose within insect cells and baculovirus and to move between the two. The environment assessment of the pink bollworm release did not discuss the likelihood that baculovirus bearing piggyBac or related transposon could rescue the inactivated piggyBac in the pink bollworm cell by genetic recombination. The interaction of the piggyBac transposon in the bollworm cell and baculovirus should be studied in the laboratory before the “contained ” field trial is allowed. The proposed trial does not “contain” the predictable interaction of baculovirus and pink bollworm. Baculovirus are known to cause non-pathological infection of human liver cells.

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    December 5, 2006

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  3. The biotech company Ventria Biosciences sponsored tests on babies and children hospitalized at two pediatric institutes in Peru, of two new experimental drugs derived from transgenic rice that was genetically engineered with synthetic human genes to
    produce artificial human milk proteins.

    The experiments – results of which were revealed this May in the US – were carried out at the Institute for Child Health and at the Nutrition Research Institute, both in Lima, Peru. The Peruvian public found out about the experiments when they were denounced by the Peruvian Human Rights Association and the Network for
    a GMO-Free Latin America.

  4. #4 Aaron Gunter
    December 11, 2006

    “The approval is a very significant milestone for the field of transgenic animal biotherapeutics,” Burlingame, Calif.-based Origen Biotherapeutics president and CEO Robert Kay, whose company is developing transgenic chickens as drug manufacturing platforms, told The Scientist.

  5. #5 Thomas Cooper
    January 22, 2007

    Advantages include reduced need for externally-applied pesticides, and cost savings and greater crop production. Disadvantages include the possibility of increased invasiveness of modified organisms, development of resistance, and cross-contamination of genetic material.