Genetically Modified Organisms (GMOs)

Any microorganism, plant or animal that has purposely had its genome altered using genetic engineering technology

Traditional Genetic Modification

• Also called Selective Breeding

• Farmers would always save the best seeds (bigger, sweeter or more resistant to disease, etc) from their crops to plant for next year.

• As a result each year the farmer got slightly better crops. Change was slight but over many generations the change was significant.

For example…..

• Balsas teosinte, a wild

grass typically found

in Mexico, was

modified into…

drum roll please……

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Modern Corn

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Transgenic Manipulation

• One or more genes are artificially inserted into the DNA of the plant’s chromosomes.

• The gene can come from the same type of plant or even another type of organism

Bt Crops

• Plants with the Bt sequence of genes can produce proteins that protect them from various insects such as European corn borer, southwester corn borer, tobacco budworm and Colorado potato beetle.

Let’s Engineer…..

• Take toxin from BT DNA and combine with a vector (What is a vector?)

• Short piece of DNA capable of replicating on its own when inside a bacterial cell.

• Now another gene which will make the plants resistant to a herbicide is added.

• The vector, which incorporates the Bt gene, is now placed into a bacterium cell.

Agrobacterium

• Causes disease in plants.

• Has the ability to transfer a portion of it DNA into plant cells

• Once inside a plant cell, its DNA will be incorporated into the DNA of one of the plant’s chromosomes.

Grow the bacterium

• By adding it to a growth medium

• Each time the bacterium divides, so do the vectors within

• Before the blink of an eye you have millions of copies of the bacterium and of the vector that contains the Bt gene

Now for the plant cells….

• Add small pieces of whatever plant you want to modify (e.g. tomato, corn) to the Agrobacteria

• The DNA of the bacteria enters the plant’s cells and the cells’ nuclei

• The vector’s DNA (which includes the Bt and herbicide resistant gene) becomes integrated with the plant cells’ DNA

Grow the plant cells

• By placing the cells into the growth medium for plants

• In the growth medium, the plant cells multiply and form stems, roots and leaves

Here comes the herbicide

• Spray the plants with a herbicide and ONLY the cells with the herbicide resistant gene survive

• Plants are transferred to a growth chamber and the plants are allowed to mature

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