From:
RRC
Date: 2001-06-09 05:05:00 UTC
Subject: Re: Bob C: A MAD Look At Genetically Altered Foods
> As a molecular biologist I feel qualified to respond to your post... I'm
> going to play devils advocate, as I mostly agree that the fear of GM foods is
> pretty hyped up.
As a molecular biologist, you probably know the subject better than I,
and if you don't, then I'm telling your committee chairman! ;-)
I can't tell you how many hours I've perched on wobbly chairs, consuming
vast quantities of beer and pretzels, playing devil's advocate on
subjects deep and important. Most people think graduate students learn
all there is to know about their subject in classes, but I'm here to
tell you that its the after class discussions were REAL knowledge is
found. I am part of an informal discussion group named "The Darwinian
Drinking Club" what meets 2 or 3 nights a week, where we discuss topics
as if we really know them. I've tried many times to generate that sort
of debate on several mailing lists, but it seems either people get
really mad at each other, or no one bites at the carefully placed baits
I've offered. I'm glad you've made some pretty intelligent comments and
asked some intriguing questions.
> That being said, I DO have questions and concerns about genetically modified
> foods. Working with genes and recombinant DNA technology I can tell you from
> personal experience that things don't always do what you think they are going
> to do. Living organsims are SO incredibley complex. There are so many
> pathways and gene interactions. Just because science has teased apart one
> aspect of a gene or pathway doesn't mean that everything has been all worked
> out.
Agreed.
> And there is a very fundamental and, IMO, important difference between
> breeding for a trait and ''inserting a trait". That is natural selection and
> the weeding out processes that occur with breeding for a trait. Artificial
> selection that occurs by human intervention, which is what breeding is
> essentially, is still governed by the laws of natural selection. This
> becomes less of a constraint when talking about GM foods. In many cases we
> are inserting genes that would never have a chance in nature of getting
> incorporated into an organsim's genome. Often these genes are not under the
> control of normal natural selection processes. The natural weeding out
> processes that would occur normally don't occur. Whether this is a problem
> or not really depends on the gene that was inserted. You put a gene in, and
> boom, it's there. What the organsim does with it over subsequent generations
> is of concern to me as well.
Crack a beer, because I'll discuss this one for a minute. Darwin's
bugaboo, which has long tainted most zoologists' view of WHAT
domesticated animals are, was that they had been REMOVED from natural
selection. He erroneously thought evolution was a process which required
natural selective pressures, such as sexual or natural selection (to
name a few). Darwin saw domestication as outside that realm, so even
though domestication resulted in a shift in gene frequencies far greater
than what is expected between, say a wolf and a fox, he did not consider
the resulting animal to BE a "new" species (He was Victorian and was
trained for the clergy; he could not escape a culture that taught that
only God created new species). Darwin came up with the term "artificial
selection" to describe how humans domesticated animals (if it isn't
natural, it must be artificial). But domestication is NOT the result of
artificial selection; it is HUMAN selection. WE did it, and there is
nothing artificial about it. The change in gene frequencies between a
wolf and dog, or a ferret and a polecat, are far greater than those
between a wolf and a coyote or the European polecat and the black-footed
ferret, yet domesticated animals areby conventionconsidered to be
variants of the progenitor species. What Darwin (and Mayr) missed is
that domestication IS evolution, and human selectionregardless of
intentis no different than any other selective force. (I guess you can
tell I am one of the minority which think domesticated animals ARE new species).
But Darwin was right about one thing; most domesticated animals are NOT
subject to NATURAL selective processes to any great degree. Natural
selection still applies to all living creatures, but it is hard to see
much pressure shifting gene frequencies when all the offspring are
living in contained chicken sheds, or munching in a pasture that is
largely predator, parasite and pathogen controlled. There is a selective
pressure rarely discussed; that of biochemistry. Bodies work only within
a very narrow range of variation, which is ALSO a selective force. For
example, consider my joke about the 4th Alien movie and how Ripley's
acidic blood should have dissolved her bones into antacids. We know that
bone is the buffer system to regulate blood pH, so it was impossible for
Ripley to have blood of high enough pH to dissolve metal. At that ph
(probably between 2 and 1, based on the reactivity), the hydroxyapatite
in her bones would have dissolved, leaving behind a cartilage matrix
that probably wouldn't support her weight (not to mention all the
problems it would have caused in disrupting the action potentials to the
muscles and nerves, or of the ability of the hemoglobin/myoglobin
complex to transport oxygen, or even of cellular metabolism to take
place). The bone buffering system can only work within a very narrow
range of variation, so ANY mutation or introduced gene which causes some
change beyond that range will result in the death of the animal. Thus
physiology is a selective pressure, and one to which ALL organisms are
subjected. I personally think it supersedes natural selection in terms
of transgenics. In short, I think any introduced gene which does not fit
within the parameters of the organism's biochemistry would result in
such disruption of physiology that the organism could not survive (or be
able to face most selective pressures). I agree that this is more of a
constraint in complex creatures, but it would still have some effect
even in microorganisms.
I agree new genes can be introduced which would never have had a chance
of being breed, but I don't think the offspring would be any less
removed from selective processes than any other domestic animal. I think
the removal of the natural weeding out processes is a phenomenon of
domestication, regardless if the vehicle of change is mutation, breeding
to cause shifts in gene frequencies, or gene insertion.
With THAT said, I readily agree that there are a lot of genes which
could be introduced which could improve the organism's fitness in ways
that cannot be foreseen. I see that as a serious problem.
> I do agree with Bob, that most likely inserted genes are not going to cause
> any big health risk, but but but..... Like I said above, organisms are so
> complex! So you prove a protein does one thing in a set of experiements.
> What's to say that protein doesn't do a whole lot of other things that you
> didn't test for, and who's to say that when you put this gene in another
> organism there's not going to be some sort of bizarre unexpected interaction
> that causes unexpected and maybe even undectable problems? In my opinion
> science has been way to cavalier about going around willy nilly recombining
> genetic material (for public consumption, let me specify), without proving to
> the scientific community public that what they're doing is okay and safe.
> This is nothing to be cavilier about! Nature has had millions of years to
> work these complex protein and/or DNA interactions out and here we come along
> thinking we can make it better. I think we can, but we need to be much more
> careful than what I've been seeing.
I've addressed some of this in the above comments. I don't know what the
exact review process is in genetic engineering. I would hope it is at
least as strenuous as the requirements for animal experimentation or
testing. I see governmental regulation as a negative thing because
technology, especially in an emerging science, rapidly makes regulations
obsolete. Regulation must come from within, but with outside observers
to insure honesty. Since you are a molecular biologist, that makes it
YOUR job, with the rest of us peering over your shoulder!! ;-)
> The concern that Bob brought up about the super pests is a VERY valid concern
> and this is much more worrisome to me that any of the other points I've
> brought up. Living things reproduce themselves; that's their job, it's what
> they do. We have to come to grips with the idea that if we put a gene into
> an organism it IS going to find a way to pass that gene on. What or who it
> passes it on to is not up to us at that point (cross species hybridization
> and transposons are two mechanisms). Nature will take it's course. That's
> it, accept it.
The danger isn't in EATING the food; the real danger is a cow engineered
to survive in a marginal environment might escape and outcompete local
animals. If we create superfit animals, we will end up with a marginal
fauna as they are replaced by a monoculture composed of what humans see
as advantageous. This is exactly what happened in New Zealand; superior
mammals (since there were no native mammals, all were superfit) were
able to best the local birds. The extinction of New Zealand wildlife was
caused by dozens of introduced mammals and hundreds of introduced
plants, introduced diseases, widespread sheep and cow ranching,
agriculture and urbanization, so it make sense to me to blame bird
declines on feral ferrets. Sometimes I wonder if working with
bureaucratic governmental agencies makes PhDs stupid.
> As a not so pimply faced graduate student I do agree with Bob that the
> scientific community needs some bad ass public relations help in this area.
> But we also need to think carefully about what we are doing, why we are doing
> it, and how we can ensure that we are not doing more harm than good.
Scientists are among the smartest, bravest, and most concerned humans on
the planet, but they suck at explaining what they do so people who are
not trained in their field can understand it. I see it on Larry king all
the time, and Larry is too stupid to realize that the inability to
explain a complex problem in 30 seconds is NOT the same as being wrong
or dishonest. Genetic engineering is very complex and difficult to
understand; most college students struggle through introductory genetics
classes. Throw in some biochemistry and they blow brown stains on their
undies. Get someone with two genes for lecturing, like me, and they
can't even say their name in less than 30 seconds. If science was easy,
there would be no need for shop classes.
> Finally, I do eat genetically modified food without much concern! (I need
> my energy so I can make more transgenic frogs!)
I love the word "transgenic." It makes me feel like I am about to fly
off to adventure. "Welcome to Transgenic Airlines. Please fasten your
seatbelts and cleave your DNA in an upright position..."
Bob C