Genomic DNA Extraction and Genomic DNA Isolation

Genomic DNA extraction is the process of releasing chromosomal DNA from the cellular matrix in which it is contained. Genomic DNA extraction requires a robust disruption method to open the nuclei and cell walls (if applicable); it usually involves adding a compatible detergent as well as mechanical shearing.

Following genomic DNA extraction is isolation, in which the proteins, cell membranes, and other cellular materials are removed yielding a purified genomic DNA sample.
 

Three general methods for genomic DNA isolation are common, and each is based on a different biochemical principle. Selection of a method is based on the throughput required, equipment available in the lab, and how the purified genomic DNA will be used.
 

Genomic DNA isolation by organic extraction involves the addition of phenol and quanidine isothiocyanate to separate the DNA and proteins into different organic phases. Organic extraction is a low-cost method and, with advanced reagents such as DNAzol, is a straightforward method requiring very little equipment.
 

DNA binds to silica (aka glass fibers) under high-salt conditions and can be released under low-salt conditions. Silica-containing columns provide an easy way to bind, wash, and elute purified genomic DNA from multiple clarified cell lysates in parallel.

Columns are designed to flow buffers through centrifugation, vacuum, or gravity. PureLink Genomic DNA Mini Kits use spin column technology and work in a microcentrifuge for easy prep of up to 18 samples at a time. Spin plates provide the same isolation technology in a high-throughput, automation-friendly format.
 

In this method, paramagnetic (attracted to magnet) beads are added to the sample, and genomic DNA binds to the beads. Using a strong magnet, the beads are held in place while removing unwanted material. After washing, the genomic DNA is eluted from the beads in water or a low-salt buffer. The bead-based method, used in MagMAX multi-sample DNA isolation and related kits, is scalable and automation compatible.