Genetic diversity analyses in Petrosia ficiformis

GenAlEx 6.5 [92] was used for the estimations of the observed (H_o) and expected (H_e) heterozygosity, and the fixation index (F_IS). Differences between H_e values among basins (Atlantic Ocean: FLO, SMI, MAD, CAN; Western Mediterranean: CAR, CART, BLA, ULL, FEL, MRS, NIZ, LIG, NAP, and Eastern Mediterranean: SLO, SCRO, JECRO, CRE, and ISR) were calculated using two-tailed T tests in Statplus 6 (AnalystSoft). In addition, Genepop on the web version 4.0.10 [93, 94] was used to obtain values for departure from Hardy Weinberg equilibrium (HWE) by locus and population using a probability test with level of significance and the following Markov chain parameters: 5000 dememorization steps, 1000 batches, and 5000 iterations per batch. Other measures of genetic diversity, such as the total number of alleles per locus and population, and number of effective alleles (=1/∑π², where ∑π² is the sum of the squared population allele frequencies) were calculated with GenAlEx and GENODIVE version 2.0b23 [95]. In order to correct for differences in sample sizes, the rarefaction method implemented in FSTAT 2.9.3.2 [96] was used to obtain the allelic richness at each locus. Clonality was assessed using GENODIVE and ignoring missing alleles.