Isolation and characterization of microsatellite loci from the endangered Mediterranean sponge Spongia agaricina (Demospongiae: Dictyoceratida)

The abundance of the bath sponge Spongia agaricina has decreased drastically in recent years and it is now considered an endangered species under Annex 3 of Bern and Barcelona conventions. We describe eight microsatellite markers and present data on their allelic variation and utility as high resolution genetic markers. We analyzed 36 individuals from two populations and found that the number of alleles per locus ranged between 1 and 7. Observed heterozygosity ranged from 0 to 0.72. We found deviations from Hardy-Weinberg expectations for some loci. We exclusively detected null alleles for those loci that deviated from Hardy-Weinberg expectations. Also, distributions of allele frequencies differed significantly between the two populations, making them suitable for population genetic analyses.