Genome sequence of the Mediterranean red coral Corallium rubrum

Corallium rubrum, the precious red coral, is an octocoral endemic to the western Mediterranean Sea. Like most octocorals, it produces tiny, calcified structures called sclerites. Uniquely, it also produces a completely calcified axial skeleton that is a bright red color. This combination of color and hardness has made the red coral prized for centuries, leading to extensive fishing and trade for use in jewelry. Understanding how it produces this red skeleton is thus a central question in economics, culture, and biology. To gain insights into this process, we sequenced the C. rubrum genome.

Our C. rubrum genome assembly is 655 megabases (Mb) in size, distributed across 2910 scaffolds with a very low level of unknown nucleotides (0.95%). We used a pipeline based on the MaSuRCA hybrid assembler, combining long PacBio reads and short Illumina reads, followed by several steps to improve the assembly, including scaffolding, merging, and polishing. This represents the third published genome of an octocoral and the first within the order Scleralcyonacea.