Environmental effects of Genetically Modified Organisms GMOs

1
Environmental effects of Genetically Modified
Organisms (GMOs)
A GM crop is a transgenic crop where gene from
another organism has been incorporated into the
genome of the crop. This crop can then pass the
transgene down to is descendents.
Positive environmental effects

• Popular claim by industry the use of transgenic
  insect-resistant Bt crops is reducing the volume
  and frequency of insecticide use on maize, cotton
  and soybean.
• New transgenic crops with tolerance to various
  abiotic stresses (e.g. salt, drought, aluminum)
  are being developed that may allow farmers to
  cultivate soils that were previously not arable.
• Herbicide-tolerant crops are encouraging
  low-till agriculture (which limits the use of
  plows), with resulting benefits on soil
  conservation.

2
Negative environmental effects
Gene flow If a transgenic/wild hybrid has a
competitive advantage over the wild population,
it could persist in the environment and disrupt
the ecosystem. (GM science review claims that
genes that are advantageous in agriculture may
not have an advantage in the wild).
Example of gene flow Case of Percy Schmeiser,
a farmer in Canada. He was taken to court by
Monsanto, the largest GM corporation in the
world, because some GMO canola plants were found
in his fields. This plant, whose fruits bear
canola oil, are wind pollinated. The court
ordered that it didn't matter how it landed up in
Schmeiser's field but it was his fault that they
were growing in his field. Schmeiser, a
recipient of the Mahatma Gandhi Award in the year
2000, lost the case and had to pay a sum of US
1,53,000 as compensation to the multinational
biotech company. (http//www.mindfully.org/GE/Schm
eiser-Gandhi-Award25oct00.htm)
3
Biodiversity loss

• "Farmers Losing Seed Varieties Worldwide"
• In the United States more than 80 of seed
  varieties sold a century ago no longer are
  available.
• The world is rapidly losing genetic diversity in
  crops (through gene flow, and through regulation
  brought by the companies holding patents).
• With development of transgenic crops, traditional
  varieties may dwindle even further as farmers
  grow a less diverse pool of crops to obtain the
  highest yields for commercial production.

Weediness / Invasives Weeds that hybridize with
herbicide-resistant crops have the potential to
acquire the herbicide-tolerant trait. More
evidence is required regarding the effect of
fitness-enhancing traits on invasiveness. These
"superweeds" would then be herbicide tolerant as
well.
4
Pesticides / Herbicides
Increased use of pesticides/herbicides 550
million acres of GM corn, soybeans and cotton
planted in the US since 1996 has increased
pesticide use (herbicides and insecticides) by
about 50 million pounds. Reduced effectiveness
of pesticides Just as some populations of
mosquitoes developed resistance to the now-banned
pesticide DDT, many people are concerned that
insects will become resistant to B.t. or other
crops that have been genetically-modified to
produce their own pesticides. Pest and weed
resistance Extensive long-term use of Bt crops
and glyphosate and gluphosinate, the herbicides
associated with HT crops, can promote the
development of resistant insect pests and
weeds. Worldwide, over 120 species of weeds have
developed resistance to the dominant herbicides
used with HT crops
5
Gene Transfer
Gene transfer into guts of bees A three year
study at the Institute for Bee Research,
University of Jena found a gene transfer from
genetically engineered rapeseed to bacteria and
fungi in the gut of honey bees. Beatrix
Tappesser from the Ecology Institute in Freiburg
was quoted as saying "This is very alarming
because it shows that the crossover of genes
takes place on a greater scale than we had
previously assumed. The results indicate that we
must assume that changes take place in the
intestinal tubes of people and animals. The
crossover of microorganisms takes place and
people's make up in terms of microorganisms in
their intestinal tract is changed. This can
therefore have health consequences."
6
Non-target species
Some transgenic traits - such as the pesticidal
toxins expressed by Bt genes - may affect
non-target species as well as the crop pests they
are intended to control. Cornell University
researchers found that monarch butterfly larvae
that were fed milkweed leaves coated with high
levels of pollen from Bt corn ate less, grew
slower and suffered a higher death rate than
larvae that consumed milkweed leaves with pollen
from non-Bt corn or with no pollen at all.
Monarch butterflies migrate through the central
U.S., where the majority of corn is grown. A
laboratory study was published in Nature showed
that pollen from Bt corn caused high mortality
rates in monarch butterfly caterpillars. Pollen
from Bt corn could coat milkweed which is what
the caterpillars eat. Losey and his colleagues
found that when they spread the pollen from a
commercial variety of Bt maize on milkweed leaves
in the laboratory and fed them to monarch
butterfly caterpillars, the caterpillars died.
7
Soil quality and fertility
The soil food web is crucial for plants to obtain
the nutrients necessary for growth. Many crops
are engineered with the Bt toxin in order to
resist infestation from insects. Yet root
exudates from these plants release the toxin into
the soil, where it retains its activity for at
least 234 days, long after its release. This
stimulates major changes in soil biota that could
affect nutrient cycling processes and change soil
fertility. Monsanto's advertising campaigns try
to convince people that Roundup is safe, but the
facts do not support that conclusion.
Independent scientific studies have shown that
Roundup is toxic to earthworms, beneficial
insects, birds and mammals (in addition to
destroying the vegetation on which they depend
for food and shelter).
8
Changes moving up through the food chain
Bt (Bacillus thuringiensis) toxins are becoming
ubiquitous, highly bioactive substances in
agro-ecosystems. Bt crops are pumping out huge
amounts of toxin from all tissues throughout the
growing season, from germination to senescence.
Most non-target herbivore insects, although not
lethally affected, ingest plant tissue containing
Bt protein which they can pass on to their
natural enemies.
9
Letting the imagination loose on this technology
Greener lawns Scott company research on lawn
grass - nicknamed "low mow" by company
scientists, has been designed to grow at a slower
pace, thereby reducing the need for a lawn mower.
Other strains could be drought-resistant, or
bred to flourish in the winter. Why not other
colored lawns? And some scientists at Scotts are
even talking about someday developing grasses in
different color. Ornamental value The company
is also working on genetically modified roses and
other flowers that will bloom longer than the
ones found in nature.
10
How do we safely grow GM crops/trees/plants? Sepa
rate these areas from areas where regular crops
grow? Giant greenhouses? How is all this
different from the genetic changes that have been
caused by humans all through time?