Spawning experiment
Total RNA from the coral branches was isolated by homogenizing 100 mg coral tissue in 1 ml TRIzol (Invitrogen) according to the manufacturer’s instructions. The RNA was then extracted once with 1 volume chloroform and precipitated in ½ volume isopropanol, washed in 1 volume of 75% ethanol and subsequently dissolved in RNase-free water. These samples were then processed through a 5 M LiCl precipitation overnight at -20º C, washed 3 times with 75% ethanol and subsequently dissolved in RNase-free water. The integrity and quality of the total RNA was assessed using a Bioanalyzer (Agilent Technology). Only the samples showing intact RNA (RNA Integrity number >8) were used for the RNA-seq analysis. The Illumina TruSeq protocol was used to prepare libraries from the RNA samples. Overall, 24 libraries of samples from the spawning experiment were run on two additional lanes in the Illumina HiSeq2000 machine using the multiplexing strategy of the TruSeq protocol.