Figure 4.

Cage tournaments—organized by genotype. (a) When all WT and KO rats from different cages met in contests in each of the three cohorts (resulting in 1320 contests), there was a loss of the phenotype that in phase I had reflected dominance by WT rats. Hatched colour coding reflects pooled data from both single-line and mixed-line cages. (b) Significant dominance of KO rats in single-line cages in contests with equivalent single-line WT rats. (c) No dominance pattern when the mixed-line cage animals competed against each other. (d) WT rats from single-line cages were dominant over KO mixed-line rats. (e) No dominance pattern when the WT mixed-line cage animals competed against KO single-line rats. ****p < 0.0001; **p < 0.01; mean ± 1 s.e.m.