Category Archives: Explainer

Extracting DNA: separating the wheat from the chaff

By Andrew Farrer

Reading the sequence of DNA molecules (the order of As, Gs, Cs, and Ts) is how ACAD researchers reconstruct the history of life. However, life at a cellular level is an intricate dance of simple and complex molecules – proteins, fats, carbohydrates – all working in concert to keep cells alive. DNA is part of this dance, the sheet music from which the music is read, providing the master copy of instructions for complex molecules such as enzymes. To ensure each of these molecules is made only when they’re needed, the DNA is not free-floating, but bound, packaged, and carefully regulated. Unfortunately, sequencing machines can only deal with pure DNA; all those other molecules will cause critical errors. So first we must separate the DNA wheat from the chaff by doing a DNA extraction.

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Figure 1: Wheat seed heads. Before the wheat grains can be used, the tough dry cases enclosing them – the husk or “chaff” – must be removed. Credit: Dako99.

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