Comparative transcriptomic analysis of and onboard fixed deep-sea limpets reveals sample preparation-related differences.

Precise gene expression reflects the molecular response of deep-sea organisms to their harsh living environments. However, changes in environmental factors during lifting samples from the deep sea to a research vessel can also affect gene expression. By using the transcriptomic approach, we compared the gene expression profiles of the onboard fixed with the fixed samples of the deep-sea limpet . Our results revealed that the concomitant stress during conventional deep-sea sampling without RNA fixation greatly influenced the gene expression. Various biological activities, such as cell and tissue structure, lysosomal activity, fluid balance, and unsaturated fatty acid metabolism, were perturbed, suggesting that the sampling stress has exerted systemic impacts on the life of the limpets. These findings clearly illustrate that deep-sea samples without RNA fixation can easily lead to biased results in gene expression analysis, which requires to be appropriately addressed in future studies.