Genetics Lab: GMOs

What is a genetically modified organism?

An organism in which the genetic material has been altered in a way that does not occur naturally by mating and/or natural recombination

What are some examples of foods that contain GMOs?

corn, soy, canola, potato, rice and squash

Why would crops contain GMOs?

Growing human population

Loss of farmable land

Remediation of soil

Enrich nutrient content

What genetic modifications can be added to crops?

Pest Resistance

Herbicide Tolerance

Viral Resistance

Drought Resistance

What are some opposing viewpoints of genetically modified crops?

Creation of super pests

Creation of super weeds

Loss of biodiversity

What are the steps of genetic modification in crops?

Choose desirable trait

Clone the gene

Engineer the gene

Transform gene into plant

Backcross GM plant into high yield crops

What is a plasmid?

a DNA carrier

What is the promotor sequence?

begins transcription

What is the terminator sequence?

stops transcription

How can we test for GMOs in food?

Grind food

2.Extract DNA from sample

3.Test sample DNA for viable

plant DNA

4.Test sample DNA for

genetic modifications

What are the functions of the PCR components?

template: DNA that’s amplified

primers: flanks to the target sequence

nucleotides: ATP, dCTP, dGTP, dTTP

magnesium: enzyme cofactor

buffer: maintains pH

Taq DNA polymerase – thermophillic enzyme from hot springs

What’s the difference between 1% and 3% gel?

Bands in 1% are tighter while in 3% the bands appear a bit more separated

How do we calculate the % agarose gel?

grams of agarose/mL of buffer x 100

Why do we amplify the plant gene?

To confirm that viable DNA was extracted and that negative GM result isn’t due to a non-viable template

What is CAMV 35S

Sequence for the promoter of 35S transcript of the Cauliflower mosaic virus

-it functions in every plant cell

What is NOS

Sequence fornopaline synthase terminator from soil bacterium Agrobacterium tumefacians

-it evolved to be recognized in most plants

Which foods can provide viable plant DNA?

corn, papaya, corn meal, and soy flour

What foods provide little to no plant DNA?

chips, fries, salad dressing, and wheat flour

Why did we use oats in the lab?

Because GMO oats don’t exist – they make

the perfect negative control

How do we know if GMOs have been detected?

if there is a band in lane 4 or not

What can cause a false positive?

contamination or lack of sterile techniques

What can cause a false negative?

No DNA extracted, the food type, or InstaGene matrix mixed in

How do we extract DNA from our food?

by grinding it

How does InstaGene matrix protect DNA?

by chelating divalent ions (e.g. Mg2+)

necessary for DNA degrading enzymes

What can cause the InstaGene matrix to become overwhelmed?

transferring over 50 μl of food

What can release food DNA into the InstaGene solution?

boiling