Data from: Evidence for a genetic sex-determination in Cnidaria, the Mediterranean red coral (Corallium rubrum)

Sexual reproduction is widespread among eukaryotes, and the sex-determining processes vary greatly among species. While genetic sex-determination (GSD) has been intensively described in bilaterian species, no example has yet been recorded among non-bilaterians. However, the quasi-ubiquitous repartition of GSD among multicellular species suggests that similar evolutionary forces can promote this system, and that these forces could occur in non-bilaterian as well. Studying sex-determination across the range of Metazoans diversity is indeed important to understand better the evolution of this mechanism and its lability. We tested the existence of sex-linked genes in the gonochoric red coral (Corallium rubrum, Cnidaria) using Restriction site Associated DNA sequencing (RAD-Seq). We analyzed 27 461 Single Nucleotide Polymorphism (SNPs) in 354 individuals from 12 populations including 53 that were morphologically sexed. We found a strong association between the allele frequencies of 472 SNPs and the sex of individuals, suggesting a XX/XY sex-determination system. This result was confirmed by the identification of 435 male-specific loci. An independent test confirmed that the amplification of these loci enabled us to identify males with absolute certainty. This is the first demonstration of a GSD system among non-bilaterian species and a new example of its convergence in multicellular eukaryotes.