While all the recent biotech limelight has been on gene
editing, especially CRISPR, another older GM crop 'improvement' technique has
continued to creep quietly up on us.
RNA interference, 'RNAi', which artificially alters gene
expression, is still with us [1].
Note. RNA interference is also known as double-stranded RNA, 'dsRNA'.
Although at the time no one actually knew why, the very
first commercial, fresh GMO venture, the FlavrSavr tomato, ripened abnormally
slowly due to RNA interference. GM
papaya with RNAi-based viral resistance has been on some markets for a long
time. Arctic apples which don't turn
brown when sliced thanks to RNAi are working their way into US shops. GM-Free Scotland readers will be aware of
Pandora's Potatoes with RNA interference to stop their bruises showing (even
although the damage is still there), to stop them turning brown when fried
(even although they taste like cardboard), to stop them producing the
carcinogen, acrylamide (even although potatoes don't produce enough
acrylamide to cause cancer), and to encourage potato growing in areas with
a high risk of late blight (even if other crops could be better grown there)
[2].
Many others are under development, but the blockbuster
everyone's been waiting for is a commodity crop with its very own RNAi-based
insecticide. This is a radical departure
from what's gone before because the artificial RNAi in the GM plant will be
designed to silence gene expression in another organism in its
environment.
Very quietly, in 2017, the US Environmental Protection
Agency (EPA) approved the first RNAi insecticide, 'DvSnf7'. It attracted very little attention from the
press or environmental watchdogs because the EPA (not for the first time)
didn't post its proposed decision in the Federal register and allowed only 15
days for public comment. The Center for
Food Safety has pointed out that this totally unprecedented use of RNAi
technology should have merited more public scrutiny.
Reassurances abound about how natural and safe DvSnf7 RNAi
is. We're told, for example, that people
are already eating stay-white fruit and veg with RNAi, and that the use of RNAi
has already proven more environmentally friendly than the use of
pesticides. RNAi, we're informed, is
highly specific, silencing only one specific gene in only one specific
species. The action of RNAi is based on
a natural mechanism which plants and animals have always used to reduce
the expression of their own genes.
"In fact," as the directors of the Donald Danforth Plant
Science Center (created with a significant donation of cash and land from
Monsanto) tell us "as a naturally occurring biological process, RNAi was
mediating plant metabolism, growth and pathogen defence long before humans
began cultivating crops for their own benefit".
In short, RNAi is SAFE because it's ubiquitous in plants and
there's a "history of safe use and consumption of naturally occurring and
transgene-derived RNAi crops". The
high species specificity minimises off-target effects. Moreover, because no GM protein is produced
in the plants, they lack toxicity and allergenicity. Who could possibly be worried?
Accordingly, the EPA initially approved four 'SmartStax Pro'
maize seed products with RNAi-insecticide to control the 'billion dollar bug',
western corn rootworm [3].
SmartStax Pro is a belts-and-braces crop with five
insecticide-producing 'Bt' genes besides DvSnf7. Scientists have already documented pests
resistant to all these Bt proteins, and Monsanto (now Bayer) researchers have
already generated rootworms resistant to DvSnf7 in order to study it. Pooling genetic resources with DowDuPont,
SmartStax Pro will also have tolerance to glyphosate, 2,4-D and FOP
herbicides.
The first wave of SmartStax Pro seed is expected in early
2020 as a 5% refuge-in-a-bag to prolong its commercial shelf-life.
If this sounds like another sprint on the same old pesticide
treadmill, it is. And even the biotech
industry is admitting it. The Center for
Food Safety points out that by ditching the current "unhealthy practices
in planting corn" and rotating a diversity of crops, farmers could get off
that treadmill along with all the GM patent-controlled seeds that are keeping
them there.
The safety of artificial RNAi in food was called into
question in 2011 by a Chinese study which detected naturally-occurring RNA
circulating in the bloodstream of people eating it. Biotech industry scientists with a vested
interest failed to replicate the Chinese study.
However, an American professor, who was aware of how difficult it is to
reliably detect RNA in a living system, tried an experiment using a different approach
to detecting RNAi: since RNAi is an active substance, she measured its effect
in a living system. It emerged that,
when laboratory mice bred to be prone to cancer were fed an RNAi construct
known to suppress cell division, their tumour burden was reduced. However, with a little help from Monsanto,
her inconvenient finding never saw the light of day [4].
OUR COMMENT
A major concern about RNAi was highlighted by the creator of
Pandora's potatoes: RNAi molecules break up the RNA they are interfering with
to release a clusterbomb of RNA fragments.
When this happens in their natural context, the debris is naturally
cleared, but artificial RNAi is going to generate artificial RNA fragments,
possibly in far larger quantities than naturally normal. These could be unpredictably active elsewhere
in the genome. Other concerns were
raised back in 2013 [4].
That same RNAi which will pass seamlessly into a pest when
the corn is eaten by it will presumably pass seamlessly into you when you eat
it. Let's hope that those assurances of
specificity, under all physiological conditions and at all ages of the human
consumer, are true because no one's checking (or if they are, the work's being
suppressed).
The Donald Danforth directors repeat just about every
assumption ever invented to 'prove' GM safe without the bother of conducting
any science.
GM proponents never seem to tire of telling us that GM is
really natural and must, therefore, be safe because we've always eaten it and
that, we may not know it, but all we're worried about is GM protein.
Make sure you never tire of pointing out any artificial
change forced into the DNA / RNA interactive, holistic complex at the basis of
life processes will have extensive side-effects, and is unlikely to be
compatible with a healthy plant, a healthy consumer of that plant, or a healthy
ecosystem of which that plant is a part.
Background
SOURCES:
- Sarah
Zhang, The EPA Quietly Approved Monsanto's New Genetic-Engineering
Technology, The Atlantic,
24.07.17
- Narender
Nehra and Nigel Taylor, Improving Crops with RNAi,
www.the-scientists.com, 1.06.15
- Aggie
Mika, First RNAi Insecticide Approved, www.the-scientists.com,
27.06.17
- Emily
Ungesbee4, Rootworm Trait Agreement, The Progressive Farmer,
17.05.18
- Caius Rommens, Pandora's Potatoes: The Worst GMOs, 2018, ISBN 9781986600835
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