Avery Experiment: DNA as the Transforming Principle @BOGObiology

Uploaded October 2021 | Updated September 2026, 2 weeks ago

The Avery, MacLeod and McCarty classic experiment helped to prove that DNA is the molecule of heredity. Previously, it was thought that proteins were the most likely biomolecule that transferred inheritance information from parent to offspring.

Avery's experiment built on the foundation of Griffith's earlier work, in which he identified a "transforming principle" that allowed bacteria to acquire characteristics from one another. In the Avery experiment, they first used process of elimination to determine that neither carbohydrates nor lipids were responsible, then tested proteins, RNA and DNA. The scientists knew that bacterial transformation should still take place unless they disabled the transforming principle. They added enzymes such as proteases, RNases and DNases to destroy various components of the bacterial mixture, knowing that most mice would die except the mice who received the injection with the disabled transforming principle.

Guided Notes & Study Guide: Check out the BOGOnotes for this video!
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0:00-0:38 Introduction
0:38-0:55 Biomolecules
0:55-1:47 Proteins vs. Nucleic Acids
1:48-2:30 Building on Griffith's Experiment on Bacterial Transformation
2:30-3:50 Preliminary Testing
3:50-4:03 The Diva Protein
4:03-4:26 Process of Elimination
4:26-4:57 Avery Experiment Design
4:57-6:24 Avery Experiment Results
6:24-7:12 Conclusions

Sources:
The Original Paper: ncbi.nlm.nih.gov/pmc/articles/PMC2135445/pdf/137.pdf

en.wikipedia.org/wiki/Avery%E2%80%93MacLeod%E2%80%93McCarty_experiment#:~:text=The%20Avery%E2%80%93MacLeod%E2%80%93McCarty%20experiment,the%20function%20of%20carrying%20genetic

openstax.org/books/microbiology/pages/10-1-using-microbiology-to-discover-the-secrets-of-life

thebiotechnotes.com/2019/12/09/averys-experiment

#averyexperiment #bacterialtransformation #moleculeofheredity

Avery Experiment: DNA as the Transforming Principle

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