General statistical analysis
Before elucidating the relationships among the methylation states,
environmental factors and individual characteristics, we used the
Kolmogorov-Smirnov test to detect whether the assumptions of normality
were satisfied. If not, a non-parametric test was employed. All
statistical tests were performed in R v. 3.1.0. The spatial analysis,
multiple regressions on distance matrices analysis (MRM) and
multivariate variation partitioning were performed as has been shown
before (Chen et al ., 2016). The details are as follows.