Genetic Engineering and GMO Detection Techniques in Plants

Organisms whose DNA has been deliberately altered by introducing genes from another organism to confer new traits.

Genetically modified organisms (GMOs)

A GM crop containing a gene from Bacillus thuringiensis that produces delta-endotoxin, a protein lethal to common insect pests.

Bt crop

The DNA sequence that serves as a docking station for RNA polymerase and signals where gene transcription should begin.

Promoter

The DNA sequence that signals RNA polymerase to stop transcription.

Terminator

A promoter from cauliflower mosaic virus that is constitutively active in all plant cell types; used in approximately 85% of GM crops.

CaMV 35S promoter

A terminator sequence from Agrobacterium tumefaciens used in approximately 85% of GM crops.

NOS (nopaline synthase) terminator

A gene that is active at all times in all cell types, not regulated by external signals.

Constitutive gene

Non-coding regions of a gene that are removed from mRNA before translation and must be eliminated when engineering a gene for use in a new organism.

Introns

An undifferentiated clump of plant cells grown from a single isolated cell on special medium, used as a target for genetic transformation.

Callus

A soil bacterium that naturally inserts its DNA into plant genomes; exploited by scientists to transfer engineered genes into plant cells.

Agrobacterium tumefaciens

A transformation method in which an electric current creates temporary pores in cell membranes, allowing engineered DNA to enter.

Electroporation

A transformation method that physically shoots gold particles coated with engineered DNA into plant cells.

Gene gun

Genes inserted alongside an engineered gene to help identify successfully transformed cells; examples include antibiotic resistance and Green Fluorescent Protein.

Selectable markers

A laboratory technique that amplifies specific DNA sequences, used to detect GM sequences (such as the CaMV 35S promoter) in food samples.

Polymerase chain reaction (PCR)

A modified version of PCR that can quantify the percentage of GM material in a food sample.

Real-time PCR

Short DNA sequences used in PCR that are complementary to and bind a specific target sequence, initiating amplification.

Primers

PCR primers that target a gene common to all plants, used to confirm that viable DNA was successfully extracted from a food sample.

Plant primers

PCR primers that target regulatory sequences commonly found in GM crops, used to determine whether a food has been genetically modified.

GMO primers

A technique that separates DNA fragments by size using an electric field through a gel, used to visualize PCR products as bands.

Gel electrophoresis

A reference ladder of DNA fragments of known sizes run alongside samples in gel electrophoresis to determine the sizes of unknown bands.

Molecular weight ruler

An antibody-based test that detects specific proteins produced by GM plants; can only be used on fresh produce and is specific to one crop type.

ELISA (for GMO detection)

The process of successfully introducing a foreign gene into a host organism's genome.

Transformation