Development of novel microsatellite marker sets for 5 common tropical hydrozoan species (Cnidaria: Hydrozoa) from the Southwestern Indian Ocean

In the context of global change, coral reefs and their associated biodiversity are under threat. Several conservation strategies using population genetics have been explored to protect them. However, some components of this ecosystem are understudied, such as hydrozoans, an important class of benthic organisms worldwide. A comprehensive study of coral reefs as a whole is needed to develop effective conservation measures. Here we describe the development of 75 new microsatellite markers for 5 hydroid species: Antennella billardi, Lytocarpia phyteuma, Sertularella diaphana, Taxella gracilicaulis and Zygophylax rufa.

Markers were tested on 246 specimens from Reunion and Mayotte islands in the southwestern Indian Ocean. Allelic diversity ranged from 1 to 21 for the 5 species, and 9 loci were estimated to have null allele frequencies ranging from 10 to 37%. Observed and expected heterozygosities ranged from 0.03 to 1 and from 0.03 to 0.93, respectively. 12 loci showed data significantly out of Hardy-Weinberg equilibrium. Cross-amplification was performed in 8 species, of which 3 showed high successful amplification rates (53 to 93%).

The estimated genetic metrics were similar to those reported for other hydroid and cnidarian marker sets. Cross-amplification showed a contrasting transferability between species, often related to the hydroid phylogeny. These newly developed markers will be relevant to the study of hydroid population genetics and coral reef conservation.