DNA and Biotechnology

What is biotechnology?

the manipulation (as through genetic engineering) of living organisms or their components to produce useful products, such as pharmaceuticals, food improvements, or fuels.

Problem: Restaurants want to be able to sell apple slices, but once you cut an apple, it begins to brown. Is it possible to create an apple that doesn't turn brown? How would you do this?

brown apple

Mini Experiment: Design an experiment to test the hypothesis that lemon juice will slow browning.

How have we modified organisms in the past?

1. Selective Breeding (artificial selection)

domesticated dogs and livestock

many traits are the result of random mutations that were perceived to have some value

Examles: plants (food) such as broccoli, cabbage and cauliflower, corn

2. Crossbreeding (hybridization)

humans can crossbreed animals and plants to produce ones with desirable traits

Examples: labradoodles, tangerines

3. Genetic Modification

Transgenic - refers to organisms that have genes from another species inserted

Examples: glow in the dark mice, bacteria that produce insulin, pest resistant crops

The papaya was saved from extinction by inserting viral DNA into it which gave it an immunity


What is a GMO?

A GMO is a genetically modified organism

Genes can be added or removed

How could we use genetic modification to create a non-browning apple?


Genetic Engineering Techniques

1. DNA extraction and Analysis

DNA is removed from the host organism, cells are broken up and the DNA is released from the nucleus.

We did this procedure with strawberries!

DNA can be analyzed to solve crimes, determine paternity, establish lineages, and diagnose disorders

Gel electrophoresis is used to separate fragments of DNA

The image shows a DNA fingerprint, the fragments of suspects can be compared to the evidence at the crime scene.

DNA fingerprint

2. Cloning

Organisms with the same genetic code are called clones

Twins are natural clones

Clone can be created - artificial twinning, and somatic cell nuclear transfer


Can we make and apple that doesn't turn brown?

1. Understand why the apple turns brown in the first place. What causing browning?

Browning is caused by the protein PPO, which is controlled by a gene

2. Why does lemon juice slow browning?

Lemon juice affects the shape of the protein, it doesn't function as well.

3. What would happen if we silenced the PPO gene?

The protein would not be produced, no browning.

4. Is the arctic apple considered transgenic?

No, it does not have new genes added, the PPO gene has been turned off.


Food for thought

1. What are some reasons for NOT wanting to label foods as GMO? (con)

2. What are reasons FOR labeling GMO foods? (pro)

3. If the law required GMO labeling, would the arctic apple need a label? Why or why not?

arctic apple