Spinal tap: Using cactus spines to isolate DNA

Isolation of DNA from some organisms is a routine procedure. For example, you can buy a kit at your local pharmacy or grocery store that allows you to swab the inside of your cheek and send the sample for DNA sequencing. However, for other organisms, DNA extraction is much more problematic. Researchers at Desert Botanical Garden in Phoenix, Arizona, have developed a novel procedure that greatly simplifies genomic DNA isolation from cactus tissue.

For members of the family Cactaceae, isolation of genetic material can be difficult due to the presence of polysaccharide-based mucilage content and other secondary compounds. Although important for water storage, these compounds necessitate the use of toxic chemicals and numerous modifications to protocols for DNA extraction. Lead author Shannon D. Fehlberg and colleagues describe a novel method for isolation of DNA using cactus spines

Considered to be modified leaves, spines contain significantly less mucilage content compared to other tissues commonly used for sampling in Cactaceae. Additionally, removal of cactus spines is less invasive than sampling epidermal tissue, which can damage plants and expose the underlying soft tissue to pathogens.

"Although you can cut a fairly small sample of epidermal tissue, this can be problematic if you are working with living collections or endangered species. Not only is it much easier to clip a spine, it is also more aesthetic and less harmful," comments Fehlberg.