2.4 RNA extraction
Total RNA was extracted from the entire CNS, and both eyes combined for each squid (ncurrent-day CO2 = 10, nelevated CO2 = 10 for each tissue) (Figure 1). Each tissue sample was homogenised in RLT-Plus Buffer (Qiagen) with sterile zirconia/silica beads (1mm diameter, BioSpec Products) in a Mini-BeadBeater 96 (BioSpec Products) for a total of 2 minutes. Total RNA was extracted using an AllPrep DNA/RNA Mini Kit (Qiagen). RNA integrity of all 40 samples was measured on an Agilent 2200 TapeStation (High Sensitivity RNA ScreenTape, Agilent) (Supplementary File S1).