It may interest readers to see the original article on which the exhange
below exchange were based.
Dr Ho has not provided evidence about her assertions that laboratory
genetic engineering is a source of new bacterial pathogens, and ignores
extensive evidence that refutes it.
Dr Ho has not analysed early evidence (1970s) that virulence genes were
mobile between bacterial species before the rec-DNA era, comprehensively
describe in Infectious Multiple Drug Resistance by S. Falcow Pion Press
1975. (eg Plasmid borne Colicin Haemolysin and Enterotoxin determinants
mentioned in Chapter 11 of that book).
Nether has she yet analysed the extensive data on genome sequences of
pathogens (eg The genome sequence of the plant pathogen Xylella fastidiosa
Nature 13 July 2000 p151 which identified 83-page derived genes, including
virulence related genes from other bacteria; AND Frequent interspecific
genetic exchange between commensal neisseriae and Neissseria meningitidis
Molecular Microbiology 36(5(, 1049-1058 (2000) which gives a specific
example of natural horizontal gene transfer between species about which Dr
Ho raises few concerns)
A comprehensive review of the huge literature on natural gene movement in
bacterial pathogens exemplified by these representative citations is a
necessary step in rigourous scholastic assessment of Dr Ho's speculations.
Dr Ho is yet to provide such a review.
David Tribe, U. Melbourne
Text of Magazine Article sent to Dr Ho:
GM-food: Secret Scientists or Obfuscatory Opponents?
Quadrant Magazine (Balmain NSW) July-August 2000 pages 38-41
Some years ago at the first Anti-genetic engineering forum, I attended,
Friends of the Earth were selling garish bumper stickers emblazoned with
the words "Genetic Engineering: Secret Sinister Science". In fact there is
little that is actually sinister and secret about this science (scientists
have to publish to survive, you see, and patents actually force
disclosure). All proposals for contentious work have to go through various
regulatory watch dogs for approval.
Senator Natasha Stott Despoja has recently declared "It's essential that
the veil of secrecy which shrouds genetically modified crops be lifted".
The public must know what science is doing to our crops and our farming'
In fact the shroud of secrecy is laying. It's not so much being used not by
the scientists, but by anti-Genetic Modification lobby groups.
The real secrecy problem is that the anti-GM activists are extremely
economical with the truth, keep many of the good points of GM technology as
secret as they can, and use rhetorical bluster to cover up the traces of
their secrecy. The scientists and the activists are getting nowhere in
debate because they speak different languages. Science values truth,
logical consistency and accuracy, and activism pure unadulterated rhetoric.
Yes, scientists tend to be a bit narrow, and many of them are, unlike
Natasha, politically naive and timid. No wonder the general public are
confused and concerned. Mostly, they think the activists are honest good
Yes, Natasha, locations of crop field trials are secret, but the lists of
field trials and companies involved are posted over the internet by the
government agency involved. Furthermore, detailed lists of Genetic
Modification (GM) projects appeared in the journal Australasian
Biotechnology the month Senator Despoja made her secrecy claim. Some
secrecy! The field trial locations of course need to be kept secret to
prevent the crops being torn up by Greenshirted eco-storm troopers, as
occurred recently with pineapple crops in a research institute in
No, Natasha, its not the scientists who are keeping secrets about GM-food,
its the anti-GM lobbyists. When they are posed searching questions, the
activists' standard response seems to be to avoid the point at issue, so
that inconvenient facts can remain secret. When this ploy fails, they fall
back to impugning the integrity of the source of inconvenient information,
an ad hominem attack pure and simple. I should know. I recently wrote an
Op-Ep piece, which appeared in the Fairfax papers, expressing a dissenting
view on GM-food to that held by the charming Natasha. For my pains, I got a
bunch of e-mails shouting 'Who is paying you. Gosh you are so narrow
minded. I choose to get my facts from scientists who aren't paid by
industry'. For the record, I am not being paid by food biotechnology
companies, and I don't do experimental work on GM-foods.
Its the benefits of genetic modification that the activists are keeping
secret. Reduction of persistent synthetic pesticides by providing more
environmentally friendly alternatives; fresh choices of herbicides, where
the new option is readily degradeable agents such as glufosinate (a natural
product) or glyphosate, instead of less desireable persistent herbicides; a
range of new options to protect plants from diseases that cause crop
failures; improvements in nutrition such as new varieties of rice with
vitamin A (which might remedy a leading form of blindness ), and rice with
better iron availability (a lack of which causes anemia in hundreds of
millions of people around the world). The potential of genetic technology
to improve crop yields has been demonstrated by a recent report that
transfer of maize photosynthesis genes into rice can improve rice yields a
thirdin preliminary greenhouse tests. All these outcomes are secrets the
anti-GM crowd what to cover up , or if they are referred to they are
described as "myths".
A few specific examples may convince the casual reader of the deviousness
of many anti-technology lobby groups when it comes to dialogue about the
issues raised by use of genetic technology in agriculture. If ever there
was a major societal and human welfare issue, worthy of serious, considered
discussion, its how to feed the world's people. In 1927 there were only two
billion of us, and by 1999 we numbered six billion. Despite predictions in
the 1960s by famous ecologist Dr Paul Ehrlich that in the 1970s that due to
lack of food, millions would starve, agricultural technology, aided by
synthetic fertiliser, and highly reliant on the efforts of plant breeders
such as Dr Norman Borlaug, ensured that this human population growth was
fed, with little expansion of farmland. In fact, productivity gains and
overall supply improvements have been so good that food prices, in real
terms, trended downwards all the twentieth century. Plant scientists have
got comparatively little praise for this, at least from the social science
based gene critics.
Important question remains unanswered by critics who focus on social
implications of technology, however. There are genuine scientific concerns
that conventional crop breeding technology, which has provided a steady
increase in crop productivity for the last fifty years or so, has reached a
point of diminishing returns, and that further yield increases from
conventional technology will be slow. The crucial agronomic issue is
whether a steady increase in food from an essentially constant (or worse,
diminishing) arable land area, can be made to cope with an expected
population growth to about nine billion by about 2050.
A typical example of how the anti-GM lobby deals with this weighty issue is
GM-food critic Mara Bun (then of the Australian Consumers Association,
currently PR advisor to Macquarie Bank). In a 1999 debate on the Nine
Network program Sunday, Mara announced that looming food supply problems
was essentially non-existent, as we have globally too much food !
(1.4-fold according to FAO statistics cited she cited). According to Mara
(and other anti-GM lobbyists such as Margaret Mellon, Luke Anderson and
Peter Garrett) the claim that gene technology is needed to feed the world
is a furphy. All that is needed is perfect and equitable food distribution
channels (utopia, I think she means).
In this worldview, we all become vegetarians, and eat only our standard
food ration everyday, and there will be (by edict?) no more dinner parties.
And there is one little secret to come, that Senator Stott-Despoja will
enjoy breaking to her Democrat friends- food prices are to shoot so far
through the roof that the GST debate will seem like a little hiccup at the
mad-hatters tea party.
More revealing is Mara's response to questioning on this issue: A TV studio
audience member at the Sunday program (one Dr David Tribe, Microbiologist,
the TV caption reads) asks Mara "Why do we have so much food?", and Mara
refuses to answer the question, put repeatedly, for about 15 minutes.
Presumably an airing of the fact that global food sufficiency is crucially
dependent on continual and continuing genetic improvement of crops is so
damaging to her case she had to try and keep the concept secret from the
Concealment by anti-GM crusaders of facts about food supply is far more
extensive than just this one particular incident. There is extensive debate
about third world food issues and the adverse effects of the 'Green
Revolution'. Anti-GM writers such as Vandana Shiva and Dr Mae-Wan Ho,
highlight the difficulties high intensity agriculture has arguably created
for poorer farmers. (It should be noted in following this debate that
GM-technology is mainly viewed by these writers as an extension of
"high-intensity agriculture". Thus in these discussions, GM-food and
"high-intensity agriculture" are in a sense synonymous, as GM-food is seen
as the high technology agriculture of the future. Some go as far as saying
that GM-food is the ground on which the organic farming and green political
movements want to attack conventional, high-intensity farming. A cynic
might also observe the anti-GM movements need (as they do) to keep secret
any successes of the food biotechnologists as these acheivements would
destroy their argument that technology will never provide for sustainable
I an no arguing that poor third world farmers difficulties should be
ignored, but neither should be the other sources of food for billions of
poor people. What is being kept secret in these discussions of third world
food difficulties is statistics on food supply. Simply put,
genetically-based high-intensity agriculture is not the exclusive province
of the rich western nations, and although not perfect, has created in the
third world, between 1970 and 1990 extra food for one billion people.
These people would not have any food had not the "Green Revolution"
improved farm output. The failure of Vandana Shiva and like minded
technology critics to duly acknowledge this fact is akin to keeping lives
saved by vaccination a secret, while only shouting concerns about rare side
Besides feeding people, farm efficiency from better breeds of crops enables
us to "tread lightly on the land", which Senator Stott Despoja's office
tell me she is passionately in favour of. India in fact provides a good
illustration of a smaller footprint made possible by plant breeding>
Beetween 1961 and 1992, plant breeders provided India a threefold increase
in wheat yield per hectare, due primarily to the introduction of new wheat
varieties. This efficiency increase avoided the need to find some forty
million hectares of fresh arable land in India (or elsewhere) for wheat
production to feed the growing population. 40,000,000 hectares is a big
ecological footprint by any measure.
THE MANTRA of the anti-GM activists is that genetic engineering does things
the like of which has never been seen on this planet. Gene technology is
radical because genes are moved between species, which never happens in
nature, so the activists say. Random insertion of DNA in new locations
within a cell is a source of new risks that we cannot predict the
consequences of. The anti-GM activists assert that the global ecological
system must be protected from this novel laboratory creation, to guard
against ecological meltdown.
As an example of this genre, the Australian Conservation Foundation's June
1999 Habitat Australia supplement "Say No! to Gene Tech's Bitter Harvest"
starts with the assertion:
'Genetic engineering enables the tree of life to be scrambled for the first
time. It allows genes to be transferred across species boundaries, from any
living organism to any other-animals to humans, humans to bacteria,
microbes to plants, and so on. This could never happen in nature or through
traditional breeding, where sows deliver piglets and roses make rosebuds.'
The ACF do not seem to realise, or care that their statement is totally
false. There is, in fact, no overarching natural law or scientifically
established biological function associated with containment of genes within
species. Those barriers that do exist may largely be just accidents of
evolution, and there is definitely no absolute genetic barrier between
To quote a recent evolution textbook (Evolution: the Four Billion Year War,
by Michael Majerus and others) "[The standard defintion of a species, using
the concept of reproductive isolation] is one which is very 'animal
centred'...many plants do not fit easily into this classification...Amonst
plants [cross-species] hybridisation events are not uncommon...most
microoorganisms, many invertebrates and all vegetatively reproducing plants
are excluded from [this]... species concept."
In fact there is evidence that much horizontal gene between species
movement has occurred in nature, and it is a subject of great current
scientific interest. For many years now studies of mobile DNA have revealed
the ubiquitous presence of jumping genes or DNA parasites that can insert
copies of themselves in random location in chromosomes.
These parasitic DNAs are extremely common in nature - for example 37 per
cent of human DNA consists of such mobile parasitic DNA. Movement of these
jumping genes is so frequent in nature that they are a common source of
natural mutations in many species. Barbara McClintock was able to readily
observe such mutations in maize in the 1940s, and studied them because they
were inexplicable in then convention genetic theory. She received a Nobel
prize for her work.
In his 1993 article "The mariner transposon is widespread in insects" in
the journal Nature, which is about a mobile gene called Mariner after
theAncient Mariner, Hugh Robertson has commented that "whatever the
mechanism Š phylogeny implies that horizontal [DNA] transfers have occurred
relatively frequently and over great taxonomic distances." Since then
hundreds of papers have confirmed this judgement. Mariner mobile genes have
been found in all animal phyla, and horizontal movement of this gene
between different phyla (not just between different species) is well
documented. Hugh Robertson has recently also reported that mariner mobile
genes invaded the human evolutionary line about fifty million years ago, so
that humans are infected with an insect gene that has jumped around to many
different locations in our own chromosomes.
A recent article on gene movement between species in the journal Science by
Elizabeth Pennisi is entitled '"Genome data shake the tree of life",
indicating the extent to which extensive new observations based on complete
analysis of complete organism gene content (genome analysis), fully confirm
and extend the now very well established concepts of mobile DNA and
horizontal gene movement.
Viruses are on of the most likely carriers for genes moving between
species. In the ocean, surprisingly, the most abundant creatures are
viruses. Jed Fuhrman has recently reviewed the ecological and genetic roles
of of marine viruses-which typically number 10,000,000,000 per litre of
surface water- and points out that viruses are prime agents for enabling
movement of genes horizontally between "unrelated" ocean species. Dissolved
DNA is also readily found in sea water and can be taken up by different
species. Fuhrman speculates that sea volumes and microorganism numbers are
such that rare gene transfers between ocean species that have a probability
of only 1 in 100,000,000,000,000,000,000 cell generations will occur a
million times a day, worldwide.
MORE TO THE POINT of this article, is how anti-GM lobbyists deal with
criticism of their assumption - the starting point of their propaganda
campaign - that genetic engineering poses a radical new risk of gene
movement never found in nature . In Australia, this is part of the public
record. Australian Conservation Foundations's Bob Phelps in discussing this
recently with me on ABC radio in Melbourne abruptly changed the topic when
faced with facts on this issue.
Overseas, the activist response to this issue is depressingly similar and
even more ethically disturbing. Recently, the prestigious National Academy
of Sciences was called upon by President Clinton to re-assess the potential
risks posed by GM-food. Among other comments, the Academy judges that
GM-foods offer "no strictly distinct risk" from that posed by
conventionally bred crops. Plant are riddled with mobile DNA, and almost
every seed would be expected to have a mobile DNA in a novel location.
According to the rules of the anti-GM activists we should fear every seed.
The response of anti-GM lobby groups to the US Academy of Sciences report
was to reject the the advice on the basis that the Academy was tainted and
biased by their connections with the biotechnology industry. Note the
response: avoid the main point of the issue being made, and instead impugn
the integrity of the source.
In trying to understand why the scientific basis for risk assessment of
GM-food has received such intellectually shoddy treatment I have read
widely anti-GM publications such as Vandana Shiva, Richard Hindmarsh, Luke
Anderson and the like. There is very little evidence in most of these
publications that mobility of natural DNA is understood as a phenomenon.
Two publications are an exception to this rule, one by David Suzuki
(assisted by Holly Dressel), Naked Ape to Super Species, and another, by
Mae Wan HoGenetic Engineering, Dreams or Nightmares?, which is used used
as a prime source of argument by Suzuki. Even these two books, despite
mentioning mobile DNA, are out of touch with the current status of mobile
DNA and seriously misleading on this topic.
Suzuki and Ho assert that genes move around infrequently in nature, but
they are very worried about a "recent" upsurge in reports that DNA
parasites 'surprisingly' are being spread around many different species in
nature. Ho's concern is that this movement has been caused by the
carelessness of genetic engineer-scientists accidentally spreading their
cloned DNA around. Susuki repeats, without offering any critical appraisel,
Ho's concern that recent infectious disease problems - namely evolution of
new antibiotic resistance and virulence in bacterial pathogens - has been
caused by the carelessness in genetic engineering laboratories. Suzuki and
Ho's assertions are unsupported by any experimental observations, refuted
by numerous scientific reports. They have not been tested through
professional scientific publication, and out of touch with current biology,
and especially microbiology.
Mobile DNA specifying bacterial virulence and resistance to antibiotics was
widely studied and identified BEFORE genetic engineering was invented
around 1975. Genetic studies prove that mobile DNA moved between species
millions of years before Suzuki was born. In the last 5 years or so about
100 different organisms have had their genetic contents totally analysed,
and these numerous studies reveal numerous new "cross-species" DNA
transfers of DNA never previously studied or used by genetic engineers, and
because they are completely novel they couldn't have been spread by
previous carelessness by genetic engineers. (DNA sequence evidence is
almost absolutely consclusive on this) One can only assume that Suzuki and
Ho havn't are unfamiliar with microbiology literature from about 1970
onward (despite Susuki's claim in his book to be an authoritative
geneticist with twenty-five years' research experience)
Criticism of this careless avoidance of well established facts of modern
biology is not academic hair-splitting. This prpaganda has been the basis
of a seemingly successful self-acknowledged putsch by Greenpeace and
Friends of the Earth that has driven GM-food out of European supermarkets.
And after this campaign, Australia is a prime target for the anti-GM
network. Already they've converted intellectually omniscient heavyweight
Philip Adams who wrote recently:
Now US corporations are on the march with genetically modified food... GM
crops that will - not might, will - currupt attempts [of Australian
farmers] to be a clean, green producer and exporter...scientists are
joining the organic food industry in warning against GM-food... And the US
government is doing everything it can to force such technologies on the
world...The corporations seeking to own our own food supplies, from paddock
to plate, should be prepared for a fight to the death.
Perhaps Adams should follow his own 'Catechism for atheists'-Worry about
something else. Do not be fashionable. Be curious. Be sceptical. Do as
little damage as possible-but add in the original commandment 'Do not bear
false witness against your neighbour'.
He should temper his anti-American posture with the knowledge that the
Peoples Republic of China has a third of its crop plantings as GM-crops.
There are even small Australian companies who will suffer collateral damage
from Adam's war. Perhaps he could tell us who the scientists are that
support the anti-GM case so that we can assess their claims.
Fortunately in science its not people's reputation that carries the day,
but the quality of their arguments and the reconcilatiation of that
argument with observations on the real world. But unfortunately, there are
a host of relevant observations about how the natural world actually
behaves that need to be bought to the attention of everyday Australians,
the people who really matter in this argument.
David Tribe teaches Biotechnology at the University of Melbourne. He has
previously written 'Myths about Mutants Muddy the Waters', (Agricultural
Science January 1997, pages 32-36) and more recently the Institute of
Public Affairs Backgrounder "Biotechnology and Food: Ten Thousand Years of
Sowing Seeds, One Hundred Years of Havesting Genes" (May 2000).