Comparisons of the roles of sex and social rank as determinants of the brain gene expression profiles. A. Hierarchical cluster analysis of all consistently expressed genes in (i) hypothalamus and (ii) telencephalon of dominant (high aggression) and subordinate (low aggression) males and females (n = 7-8 fish per group) and the corresponding PCAs performed on the profiles of the same individual fish in (iii) hypothalamus and (iv) telencephalon) (the dashed lines were drawn arbitrarily to aid the visualisation of clustering of the samples). B. Hierarchical cluster analysis of genes identified as differentially expressed (P < 0.05) between (i) dominants (high aggression) and subordinates (low aggression) irrespective of their sex, and (ii) between males and females irrespective of their social rank. Fish are shown individually. In (i), individual male fish are indicated by numbers in blue and individual female fish by numbers in pink (all genes were overexpressed in dominant fish). In (ii), individual dominant fish are indicated by numbers in red and individual subordinate fish by numbers in black. In (i)-(ii), genes shown in red were overexpressed in females while genes shown in green were overexpressed in males. Grey colouration indicates no data.