Why is RNA extraction tougher than DNA extraction?

The main reason is that RNA is less stable and easier to degrade compared to DNA. There are three main causes for RNA degradation:

• RNA is more reactive than DNA because of the ribose units in its structure, which have a highly reactive hydroxyl group on C2 that takes part in RNA-mediated enzymatic events.
• RNA is single-stranded, while DNA is mostly double-stranded. RNA has larger grooves than DNA, which makes it easier to be attacked by enzymes.
• Enzymes that degrade RNA, ribonucleases (RNases) are abundant in environment and hard to be removed completely. For example, autoclaving a solution containing bacteria will destroy the bacterial cells but not the RNases released from the cells. Furthermore, even trace amounts of RNases are able to degrade RNA.

Therefore, RNA isolation requires cautious handling of samples and good aseptic techniques. It is important to use only RNase-free solutions during the extraction, as well as RNase-free pipet tips and glassware.