Genetically Modified Crop Plants

Genetically Modified Crop Plants

Genetic Engineers CanModify Food

• Transgenic organisms are produced when a gene from one organism is incorporated into the genome of another

• The more popular term for transgenic organisms is GMO, for genetically modified organism

• GM foods means genetically modified

GMO examples

Genetically Modified Food

Inserting the Gene

Inserting the Gene

Inserting the Gene

Pros to Creating Genetically Modified Food

Pros to GMOs

• Better resistance to weeds, pests, disease

• Better texture, flavor, nutritional value

• Longer shelf life, easier shipment

• Better yield, more efficient use of land

• Less herbicides and other chemicals

• Essential if we are to feed the world

Cons to Creating Genetically Modified Food

Cons to GMOs

• They can have harmful effects on the human body– It is believed that consumption of these

genetically engineered foods can cause the development of diseases which are immune to antibiotics.

– These foods are new inventions, not much is not known about their long term effects on human beings. As the health effects are unknown, many people prefer to stay away from genetically modified foods

Cons to the Environment

• Creates “super weeds”

• Creates “super bugs”

• Effects natural ecosystems

Bt and the Monarch butterfly

• Bacillus thuringiensis (Bt) is a soil bacterium that produces insecticidal toxins.

• Genes from Bt can be inserted into crop plants to make them capable of producing an insecticidal toxin and therefore resistant to certain pests.

• Bt corn can adversely affect non-target insects if they are closely related to the target pest, as is the case with Monarch butterfly

Genetically Modified Foods in the U.S. Diet

• Over half of all food in U.S. market contain at least some GM foods

– Most soybeans grown are modified for herbicide resistance

– GM corn – an ingredient in most processed foods – is common as well

– GM canola and cottonseed oils are used in a huge range of food products

FDA Regulations

• Manufactures must get FDA approval for an food not generally recognized as safe (GRAS), including new genetically engineered food substances

• The FDA declared milk from rBGH cows safe for consumption in 1993

How Are GM Foods Evaluated for Safety?

• The EPA must approve all GM crops• GM foods can cause allergic

reactions (8% of us are allergic to foods)

• Newly inserted genes may also encode proteins that prove to be toxins

DNA Technology and Genomics

Genetic Engineering/ DNA Technology

3 types of Cloning Technologies:

1. Recombinant DNA Technology/ DNA Cloning

2. Reproductive Cloning

3. Therapeutic Cloning

Cloning the bovine growth hormone (BGH) gene

Recombinant DNA Technology/DNA Cloning

Cloning a Gene

• Cloning means making many copies of a gene

Recombinant DNA Technology/DNA Cloning

1. Remove the Gene of Interest2. Cut the Plasmid DNA3. Insert the Gene into the Bacterial

Plasmid4. Insert the Recombined Plasmid

into the Bacterial Cell5. Let the Bacteria Reproduce

1. Remove the gene of interest (ex: BGH gene) using restriction enzymes

Restriction enzymes cut DNA at specific sequences called palindromes . . .

Restriction Enzymes Leave “Sticky Ends”

Restriction Enzymes

• The unpaired bases on the sticky ends form bonds with any complementary bases with which they come into contact

2. Cut the Plasmid DNA with the Same Restriction Enzyme

3. Insert the Gene of Interest into the Bacterial Plasmid

(The bacterial plasmid is also cut with the restriction enzyme, leaving sticky ends)

4. Insert the Recombined Plasmid into a Bacterial Cell

5. Let the Bacteria Reproduce

Other Proteins Made by DNA Cloning:

•Insulin for diabetics•Clotting factors for hemophiliacs

Basic Versus Applied Research

Basic research

• no profit motive or direct commercial application – generally government funded

Applied research

• immediate and profitable application – generally privately funded

Reproductive Cloning/Cloning Entire Organisms

Reproductive Cloning

• Technology used to generate an animal that has the same nuclear DNA as another curretly or previously existing animal

Steps in Nuclear Transfer

Steps in Somatic Cell Nuclear Transfer

Results of Nuclear Transfer Experiments

There were 277 failures before this nuclear transfer technique succeeded;

Reproductive Cloning

Dolly was successfully born in 1997

Reproductive Cloning

• Dolly was put to sleep at the age of 6 in 2003

• She was suffering from arthritis and a progressive lung disease

• These are usually only seen in old sheep

Other Organisms Reproductively Cloned

Mouse

Cow

Goat

Mule

Horse

Rabbit

Cat

Pig

Dog

Rat

Deer

Why Do Reproductive Cloning?

Have We Reproductively Cloned Humans?

Opposition and Support of Human Cloning

What do YOU think?

Therapeutic Cloning/ Embryo Cloning

• Instead of cloning entire organisms, there is therapeutic cloning

• Stem cells are induced to turn into specific tissue cells

Therapeutic Cloning

The Human Genome Project

Sequenced the entire human genome

Goals of The Human Genome Project

Organisms With Genome Sequenced

Rhesus Macaque

Fruit Fly

Zebra fish

Potato

Many organisms have genome projects that have either been completed or will be completed shortly, including

:

•Humans•Neanderthal•Haemophilus influenzae, a bacterium•Common House Mouse•Brown Rat•Common Chimpanzee•Rhesus Monkey•Domestic Chicken•Domestic Cat•Domestic Dog•Common fruit fly•Baker's yeast

Many organisms have genome projects that have either been completed or will be completed shortly, including

•Red bread mold,

•Thale Cress

•Rice

•Common Wheat

•Corn

•Poplar Tree

•E. coli bacteria

•SARS virus

•Nematode worm

•Zebra fish

•Tomato

•Potato

•Western Honey Bee

•Grapevine

•Spanish flu virus

The Human Genome Project

• These were used as model organisms in genetic studies

• These model organisms contain genes that are the same as human genes

Gene Testing

DNA Chips

Pros and Cons of Gene Testing

Gene Therapy

• Once the genetics are worked out, gene therapy can be researched

• Replacing defective genes with functional ones

– Germ line gene therapy in embryos– Somatic cell gene therapy in

individual somatic cells in affected tissues

Gene Therapy

• Germ Line Gene Therapy

• Somatic Cell Gene Therapy

Gene Therapy

• Non disease causing virus is genetically engineered with the functioning gene that is needed in SCID patients

• The virus infects the immune cells and the immune cells get the functioning gene

Gene Therapy

Gene Therapy

• Treatment for SCID (severe combined immunodeficiency)

• Gene therapy in cells of the immune system

Somatic Gene Therapy

• is not widely used

• Is only for single gene disorders with cells that can be removed, engineered and then replaced in the body

Somatic Gene Therapy

• The condition may still be passed to offspring, because somatic cell gene therapy does not treat all the cells in the body

Setbacks to Gene Therapy

1.Treat Cancer

2. Gene Therapy to treat inherited form of blindness is successful!

Recent Successes in Gene Therapy