Genetically Modified Organisms

- plants, animals, microorganisms

- add or take away traits

Why use GMOs?

-old method:traditional breeding

-new method: direct introduction of desired trait

How are organisms genetically modified?

(I) Direct DNA transfer

(II) Vector assisted transmission

electroporation

biolistics (plants)

microinjection

Wound near base of stem

Agrobacterium tumefaciens

Bacteria invade wound

Healthy plant

Rapid cell division in plant -Crown Gall

T-DNA (oncogenes)T-DNA (oncogenes)

Virulence region

Host specificityregion

~200 kb

Tumour Inducing Plasmid of A. tumefaciens

T-DNATiTi

integrated T-DNA

Plantchromosomal

DNA

T-DNAT-DNA

Plant DNA

rapid cell division synthesis of opines

Plasmid invades plant cell

T-DNA of a wild type Ti plasmid

Oncogenes - auxin synthesis, cytokinin synthesis, growth stimulation

iaaH iaaM ipt nos

Gene transfer using the T-DNA of a plasmid

promoter terminator

selection marker- kanamycin

gene(s) of interest

Golden Rice

When is a carrot not a carrot?

Herbicide resistance built in to maize

BtBt Cotton Cotton

Cotton Boll Weevil

Monarch Butterfly

Improving health careImproving health care

Vaccines - CholeraVaccines - Cholera

Insulin Dependent Diabetes

Clearing up after war

BioSteel

Nephila clavipes Capra hircus

Transgenics - example of inactivated genes

Antisense strategy

-blocking of enzyme synthesis to improve the quality of fruit

e.g. polygalacturonic acid in tomato the “Flavr Savr”

Types of modifications introduced into plants between 1987 and 1999

Herbicide tolerance 30%Insect resistance 25%Product quality 20%Resistance to viruses or fungi 15%Agronomical qualities 7%Other 3%

Examples of introduced genes

Herbicide resistance

Resistance to plant pathogens

Improvement of nutritional qualities

Health care

Resistance to abiotic stress

Increased Production or Yield

Safety Matters

Other….

The scaredy goat

Tennessee Fainting Goats