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Standard: Students will analyze how biological traits are passed
on to successive generations.
Element: Examine the use of DNA technology in forensics,
medicine, and agriculture.
EQ: How is DNA technology used in agriculture?
In agriculture today, farmers often produce crops or
livestock that have DNA from different organisms. As you
already know, inserting genes (sections of DNA) into the
genome of another organism is called recombinant DNA.
These inserted genes are intended to make the organisms
bigger, stronger, and more resistant to disease.
Organisms with recombinant genes are called
transgenic organisms also known as G.M.O.'s.
G.M.O. stands for Genetically Modified Organism.
Most corn and soybean products sold in grocery stores in
the USA are made from GMOs. In many cases, the crops
have a gene added from the bacteria Bacillus
thuringiensis (Bt). The gene produces an insecticide that
prevents pests from eating the crop. Many food crops are
engineered to be easier to grow or to be more nutritious.
Bt Corn
Unlike a transgenic organism, a clone is an
organism that is an exact genetic copy of another
organism. Their entire DNA is identical. Clones
can happen naturally (twins) or artificially by
Somatic Cell Nuclear Transfer (SCNT).
Steps of Somatic Cell Nuclear Transfer:
1. An egg cell is removed from an organism,
placed in a petri dish, and the nucleus is
removed.
2. The nucleus from a somatic (body) cell is
removed and then inserted into the
enucleated (without nucleus) egg cell.
3. The egg cell is then stimulated with a
chemical or electric current until it starts
to divide and form an embryo.
4. The embryo is then implanted into a
surrogate (substitute) mother who gives
birth to the newly cloned organism.
Questions:
1. What is the difference between a
transgenic organism and a clone?
2. What are the advantages/disadvantages of
genetically modified foods?