Quantitative expression of putative immune and stress-related genes. The quantitative expression of putative genes from vent mussel gills tissues was assessed by qPCR. Data were transferred to Excel files and plotted as histograms of fold expression of putative genes from non-normalized cDNA library. Results are mean ± SD (N = 3). Vertical bars represent the relative expression levels of putative transcripts using the 28S as control and normalization gene.