RNA extraction and sequencing
Foot and mantel tissues of Coelaturini specimens from Malawi, Uganda and Zambia were stabilized in RNA-later for subsequent RNA extraction. Extractions were performed with the NucleoSpin RNA Plus kit of Machery-Nagel, either according to the protocol of the manufacturer, or by adding Proteinase K to the lysis buffer. Tissues were disrupted with magnetic beads (matrix D, 3× 30 s at a speed of 6 ms, MP). The quantity and quality of mRNA was quantified with high-sensitivity Qubit fluorometry (Life Technologies Inc.) and with an Agilent BioAnalyzer. We selected 12 samples from several major clades of Coelaturini based on the phylogeny of Ortiz-Sepulveda et al. (2020) for sequencing: Six specimens of Coelatura hypsiprymna and C. nyassaensis from Lake Malawi Basin; two of Grandidieria burtonifrom Lake Tanganyika; two of Coelatura hauttecoeuri and two of Nitia acuminata from Lake Victoria (Table S1). RNA extraction products were purified and poly-A enriched for cDNA strand-specific, paired-end library preparation with the TruSeq RNA sample preparation kit v2 (Illumina). The resulting libraries were sequenced on an Illumina HiSeq 3000 platform v3.0 (2×150 bp). Purification, library preparation and sequencing were outsourced to UMR AGAP of the INRA and the University of Montpellier.