I am working with tissue samples from a marine fish that have been preserved in alcohol for 2–4 years. The alcohol has not been changed during this period. I have successfully extracted DNA from some samples using the TIANGEN Blood and Tissue Kit. However, older samples, which appear degraded, molten, and have a strong odor, did not yield any visible bands on gel electrophoresis.
Given the degraded state of these samples, I am looking for an alternative DNA extraction method and kit that would improve DNA recovery. Could anyone recommend a suitable protocol or modifications (e.g., pre-treatment steps, enzymatic digestion, or commercial kits) that have worked for similar degraded tissue samples? Any insights would be greatly appreciated.
Extracting high-quality DNA from degraded marine fish tissues preserved in alcohol can be challenging due to factors like tissue degradation and the dehydrating effects of alcohol. However, several studies have evaluated different DNA extraction methods to determine the most effective approaches for such samples. Saline (NaCl) Method: This method has been shown to yield high-quality DNA from fish tissues. In a study comparing various extraction protocols, the saline method provided DNA of satisfactory concentration and purity, making it suitable for downstream applications like PCR and sequencing.
For degraded, alcohol-preserved fish tissue, try the QIAamp DNA FFPE Tissue Kit or the DNeasy Blood & Tissue Kit with modifications. Add prolonged proteinase K digestion (overnight) and rehydrate with TE buffer to improve DNA recovery.