How is foreign DNA inserted into organisms during the genetic engineering of crops?

Akiva Friedman

White Plains High School

Summer Research Program for Science Teachers

Summer 2006

Do Now:

Circulate a copy of an excerpt of N.Y. Times Business Section, August 19, 2006:

In Error, Rice Crop is Mixed With an Unapproved Strain by Andrew Pollack

“Small amounts of an unapproved strain of genetically engineered rice have been found in samples of supplies destined for human consumption…”

…”The rice, developed by Bayer CropScience, contains a bacterial gene that causes the crop to produce a protein that makes it resistant to the herbicide Liberty, also known as glufosinate.”

Teacher should act as facilitator of a discussion of positive benefits and negative consequences of genetically modified organisms.

Mini Lesson: Day 1 – Background and Notes

This part of the lesson is a primer lecture covering key biotech concepts and techniques. Proper questioning technique may elicit answers from students and decentralize the teacher’s role in the acquisition of information.

• How is DNA structure related to protein synthesis?

• Why is E. Coli used in biotechnology applications?
• How is plasmid DNA separated from all other parts of bacteria cell?
• What is the function of restriction enzymes?
• How does ligase work to insert DNA into vectors?
• How do you transform competent cells via heat shock?
• How do you prepare an overnight culture?

Differentiating the mode of instructional delivery can strengthen this lecture/notes segment. Certain students may require a pre-note template with a list of key phrases to guide them through the background vocabulary. For example:

• DNA is responsible for                                  synthesis.
• Restriction enzymes are used to                              DNA.

 Overheads with diagrams are a key element when presenting scientific concepts.

Final Summary: Day 1

• Discuss genetic engineering of insulin production for diabetics.
• Insert human insulin geneà bacteria DNA.

Group Activity Directions: Day 2 - double period lab

Each group is responsible for its own materials.

1. Prepare samples of pRES115 plasmid DNA, EcoR V enzyme, BSA, water, and buffer from Quiagen DNA prep kit.
2. Use pipettes and microcentrifuge tubes to combine 5 microliters of DNA, 2 microliters of BSA, 2 microliters of buffer, 10 microliters of water, and 1 microliter of EcoRV.
3. Incubate 1 hour.
4. Use prepared gels, ladders, and dye and run analytical gel for 30 min at 120 V.
5. Clean up your lab station.

Final Summary: Day 3

• Instruct students on how to read the gel electrophoresis results. Plasmid DNA should travel at a different rate compared to linear DNA.

·    Students will present their findings as lab groups.

·    Students shall discuss sources of lab error.

References to National Science Education Standards

Life Science Content C

• …“The genetic information stored in DNA is used to direct the synthesis of thousands of proteins that each cell requires.”
• “In all organisms, the instructions for specifying the characteristics of the organism are carried in DNA, a large polymer formed from subunits of four kinds (A, G, C, and T)…”

Educational Principles

• “Learning science is an active process.”
• “School science reflects the intellectual and cultural traditions that characterize the practice of contemporary science.”