Introduction to GMO Debates and How to Make a GMO

Rensel: 10/29

Where do the majority of molecular biology tools used in the lab to engineer plants/animals, such as enzymes, come from?

A) They were originally discovered in plants

B) They were originally synthesized in the lab

C) They were originally found in bacteria 

C) They were originally found in bacteria 

Which of the following is true about a good vector for transporting a gene of interest into a host cell?

A) It should make the host cell sick, leading it to die quickly 

B) It should be larger than the host cell

C) It should have the ability to “infect” a host cell in nature

D) It should be able to rapidly mutate

C) It should have the ability to “infect” a host cell in nature

The main difference between transgenic and gene-edited (e.g., CRISPR) GMOs is:

A) Safety testing is always required for transgenic GMOs but not for gene-edited GMOs

B) Transgenic modifications affect 1-8 genes while gene editing techniques change the entire genome 

C) Transgenic modifications are cheaper than gene editing 

D) Transgenic GMOs have (foreign) genes inserted at desired locations in their genomes, while gene editing typically alters the organism’s own genome  

D) Transgenic GMOs have (foreign) genes inserted at desired locations in their genomes, while gene editing typically alters the organism’s own genome  

What types of GMOs are Roundup Ready corn and Bt corn?

A) Drought-tolerant GMO; Insect-tolerant GMO

B) Herbicide-tolerant GMO; Insect-tolerant GMO

C) Insect-tolerant GMO; Pesticide-tolerant GMO

D) Herbicide-tolerant GMO; Heat-tolerant GMO

B) Herbicide-tolerant GMO; Insect-tolerant GMO

Say you’ve identified a gene for drought tolerance in a bacterium, and want to introduce this gene into your soybean crop. What’s the correct order of the process?

1) Isolate the drought-tolerance gene from the bacterium.

2) Insert the gene into a vector, such as a plasmid.

3) Insert the recombinant DNA plasmid into a bacterium and allow it to replicate. (transformation)

4) Induce the host soybean cells to take up the recombinant DNA, so it can express the gene for drought tolerance.

How are modern GMOs different from traditionally-bred crops?

Modern GMOs have foreign genes inserted (recombinant DNA) or edited from their own genome to produce specific traits, but leave the rest of the genome as it is. They involve direct manipulation of DNA and the ability to insert DNA from different species or taxa. Traditionally-bred crops mix entire genomes by selecting crops with desired traits and cross-breeding them over generations. Modern GMOs are also paired with farming methods to produce high-yields, efficiency, and mechanization.

List and describe the main enzymes involved in making transgenic crops. What role do they play in the basic GMO molecular toolkit?

The main enzymes involved in making transgenic crops are DNA ligase, Taq polymerase, and restriction enzymes. Restriction enzymes cut plasmids and foreign DNA at specific sites, allowing the isolation of genes of interest. DNA ligase sticks these ends of DNA together to create a recombinant DNA molecule. Taq polymerase is a heat-resistant enzyme that replicates target DNA sequences in PCR to make many copies of the recombinant DNA to be taken up by the crops.

This type of genetic modification allows crops to survive applications of weed-killing chemicals.

herbicide tolerance (HT)

Name one molecular tool commonly used to insert genes into a plant's genome.

plasmid or Ti plasmid

This bacterial enzyme, essential for polymerase chain reactions (PCR), is derived from Thermus aquaticus.

Taq polymerase

Approximately what percentage of processed foods in the United States contain genetically modified ingredients?

60% - 70%

Identify the three main steps of PCR used to amplify genetic material.

denaturation, annealing, extension

This term refers to the combined genetic material of two or more organisms

recombinant DNA

This quality makes a good vector for transgenic GMOs

ability to “infect” a host

These are the 3 main methods of crop modification discussed in class

1) traditional breeding

2) mutagenesis

3) RNA interference

4) transgenics

4) gene editing

This method of crop modification often (but not always) relies on altering the organism’s own genome, not adding foreign DNA (“transgene-free”) 

CRISPR gene editing

These are in the basic molecular toolkit for making a transgenic crop

1) Enzymes derived from bacteria

DNA ligase

Taq polymerase

restriction enzymes

2) Vectors derived from bacteria or viruses

3) Bacteria to make copies of the recombinant DNA