Figure 2. Convergence of PFAM domain contents of Arctic-specific algae.

Violin plots of Bray–Curtis indices calculated between PFAM distributions of pairs of algal genomes (top) or transcriptomes (bottom), separated by habitat: Arctic (isolation site > 60°N, within Arctic water masses), Antarctic (isolation site south of the polar front of the Antarctic Circumpolar Current), or other (all intermediate latitudes). Comparisons between members of the same taxonomic group and involving either freshwater or obligately non-photosynthetic species were excluded from the analyses. As there was only one Antarctic genome (Fragilariopsis cylindrus) in the pan-algal dataset, it was not considered in the genomic comparisons. Significance values of one-way ANOVA tests of the separation of means (red dots) are provided between Arctic–Arctic strain pairs and all other forms of strain pairs considered.