A lot of confusion surrounds the idea of GMO, or genetically modified organisms. The most
common misconceptions involve confusion between hybridization of plants and genetic
engineering.
A hybrid is created
by breeding species of the same genus.
This is called "conventional breeding" and it employs processes that
occur in nature, such as sexual and asexual reproduction. The
selected characteristics are not new for the species. Common plant hybrids are
Leyland Cypress, peppermint, grapefruit and wheat. You might also picture
dog/horse pedigree charts where certain traits are cross bred for specific
outcomes. Or perhaps you picture the genetic selection chart from your high
school biology or horticulture book, where you charted your family traits or even
cross bred a flower.
By definition a GMO product
has had its genome altered. This is
called recombinant DNA technology. Genetic
engineering works primarily through insertion of genetic material. Engineers
must also insert a "promoter" gene from a virus to make the inserted
gene express itself. This allows insertion of DNA from other genus.
When I teach GMO we always start with taxonomy so that students understand the division of kingdoms(1) and the classification of species(2) within each kingdom. We then
look specifically at insect classification (animalia kingdom) to enforce the concept
of classification and introduce identification of characteristics (ie:hard/soft
bodies, two wings). Hybridization is studied when we identify and classify
plant characteristics within the plantae kingdom. I introduce GMO last, after a
lab where we extract DNA from a strawberry. GMO can take a gene from a bacteria
and put it in a plant. Students then understand that the engineering crosses genus
and even kingdoms. DNA "jumps" across the classification chart in opposition
to evolution and adaptation.
Look at the chart below and think through the process of
extracting Bt bacteria (monera) and introducing it into corn (plantae), a widely talked about GMO
controversy. GMO corn contains a soil bacteria that kills the cutworm by
"exploding" its intestines. We do not know how this affects humans or
animals who eat the corn as feed. This is why many people are upset. There are
many benefits to GMO, but there are also many controversies.
GMO products include medicine and vaccines as well as
biopesticides and bioherbicides. Other benefits do include increased nutrients,
yields and stress tolerance of crops and animals. Environmentally GMOs
contribute to conservation of soil, water and energy and provide food security
for growing populations.
HOWEVER, there are potential human health impacts including
allergies, transfer of antibiotic resistance, and unknown health effects. A major environmental impact that we are
already seeing is cross pollination contamination in crops and there are
unknown effects on soil microbes and flora and fauna diversity.
Most of the controversy today revolves around intellectual
property rights, ethics, labeling and right to know, and societal impact, as
well as human health.
Studies indicate that almost all soybeans, corn, alfalfa, cotton
and canola grown in the US is GMO. But the US does not require labeling so the
average American does not know their food contains GMO. This is possibly the
largest controversy, the right to know in a country that prides itself on
citizen rights.
Keep in mind that all organisms are evolving and adapting. There
are phenomenal examples in nature. I encourage you to seek out and watch Queen
of Trees (Nature series). Once we alter a genome evolution and adaptation
begins. This is a huge, irreversible, human impact on our environment that
everyone should understand.
******
(1) Five-Kingdom System:
Animal Kingdom –
Invertebrates (without backbones) and vertebrates (with backbones),
multicellular, no cell walls, obtain energy through respiration
Plant Kingdom – multicellular, have cell
walls, obtain energy through photosynthesis. Ex. mosses, ferns, flowering and
seed plants
Fungi Kingdom – cells with cell walls
but not green and do not carry out photosynthesis, break down other organic
materials to obtain food. Ex. mushrooms and molds and yeasts
Protist Kingdom –
come in a wide variety of forms, some are animal-like, such as amoeba,
paramecium and protozoan. Some are plant-like such as algae and others are
fungi-like. Many are single-celled and others are multicellular.
Monera Kingdom –
some photosynthesize while others respire. The nucleus of moneran cells are not
bounded by nuclear membranes like cells in the other kingdoms. Ex. bacteria
and blue-green algae
(2)The classification of humans – Homo sapiens
Kingdom: Animalia
Phylum: Chordata
Class:
Mammalia
Order:
Primata
Family:
Hominadae
Genus:
Homo
Species:
sapiens
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