Effects of Freshwater Pollution on the Genetics of Zebra Mussels (Dreissena polymorpha) at the Molecular and Population Level

Table 4

Analysis of molecular variance (AMOVA) over all six microsatellite loci for field populations.

Source of variation	Sum of squares	Variance component	% of total variation	Fixation index	𝑃 value
Among groups	2.320	−0.001	−0.060	𝐹CT=−0.001	0.556
Among age classes within groups	9.843	−0.002	−0.069	𝐹SC=−0.001	0.542
Among individuals within age classes	222.574	0.077	3.172	𝐹IS=0.032	0.044
Within individuals	223.000	2.354	96.957	𝐹IT=0.030	0.043
Total	457.737	2.428

The results are weighted averages over all six loci for 85 individuals comprising two populations and divided into three age classes. For the group level, the individuals of the three age classes belonging to the same population were pooled. Listed are the source of variation, sum of squared deviations, the variance component estimates, the percentage of total variance, the fixation indices, and the significance of the variance components and of the fixation indices estimated by performing 1023 permutations for the analyses. Note: small negative variance components; % of total variation and fixation indices are statistical artefacts and are observed among entities with very low genetic differentiation (here groups and age classes).