Microsatellite loci for the host-generalist “zooxanthella” Symbiodinium trenchi and other Clade D Symbiodinium

Nine new polymorphic microsatellites were developed for Symbiodinium trenchi (sensu type D1a ). These loci were tested on populations of S. trenchi from corals in Palau and 3–19 alleles were observed at each haploid locus with an average of 7 alleles. Many of the primer sets successfully amplified loci within other members of Symbiodinium clade D, demonstrating their utility across the group. Clade D Symbiodinium spp. are generally regarded as thermally tolerant and are common in coral reef habitats with warm, turbid, and/or variable environmental conditions. These population genetic markers are therefore useful for investigating how stress-tolerant symbionts may respond to climate warming through range expansion and/or by developing new associations with various host cnidarians. Additionally, the cross-lineage utility of these markers should help delineate the evolutionary relationships among members of this clade.