Fig. 4.—

Fusions and fissions across the salmonid lineage. Different fusions and fissions have occurred during the evolution of the salmonids. White boxes display the fusion events, where the homologous chromosomes for all species are named according to the corresponding Northern Pike linkage group ID, with.1 or.2 to correspond with the post-duplicated salmonid chromosomes. Bold and underlined chromosome numbers are the homeologous pairs that exhibit residual tetraploidy, and the italicized chromosome (6.1/6.2) does not exhibit residual tetraploidy in Atlantic Salmon but does in the Pacific salmonids. Above the species names are conserved fusions, whereas below are the species-specific fusions. Also shown are the most likely timings of fissions in light gray boxes with the notation Fi^x, where x corresponds to the superscript number on the original fusion. For example, the fusion 4.2–20.1² at point (F) in the phylogeny probably underwent fission at Fi² prior to D. The phylogeny is adapted from (Stearley & Smith 1993; Kinnison & Hendry 2004; Crête-Lafrenière et al. 2012), with minor modifications to the relationships within the Pink, Chum and Sockeye Salmon clade, as described in the results. Branch lengths are not to scale and are for illustrative purposes of relationships between species only.