Extraction of DNA

Obtaining plant DNA of sufficient quality and quantity is an important consideration for MAB. Figure 1 shows a step in a DNA extraction procedure.

Figure 1: A  Laboratory technician carefully adds chloroform to a large DNA extraction prep.  (Image provided by Theresa Fulton.)

There are many DNA extraction protocols available.   No matter the protocol chosen, though, each will follow these four main steps summarized nicely in Wikipedia:

  1. Break cell wall (grinding, shaking, etc.)
  2. Freeing the DNA from the nucleus and surrounding membrane lipids (detergent, enzymes) (See Figure 2 for refresher on cell components.)
  3. Precipitate out the DNA to wash off other contaminants (alcohol)
  4. Redissolve the DNA in a clean aqueous solution

This DNA Extraction animation visually depicts these laboratory steps (Sherman and Quinn)

While watching this next animation by Hain and Ehly (2000), which focuses on DNA structure, note the order/sequence of events: Plant cell-> Nucleus-> Chromosomes-> Fine structure of chromosome-> DNA double stranded helix-> Nucleotide pairs/order-> Genes –> Proteins-> Traits

Figure 2: A plant cell diagram illustrating various components. DNA is normally extracted from chromosomes found within the nucleus.  Image from Plant and Soil Sciences eLibrary