Fig. 4.

The pipefish hox clusters have experienced convergent and unique gene losses. A cartoon of the hox clusters in S. scovelli, with boxes representing genes arranged along chromosome segments of different linkage groups, summarizes gene content changes relative to other teleosts. Seven gene losses, of both coding and non-coding genes, are here labeled shared losses among the compared percomorph lineages because these genes are retained by the non-percomorph outgroup, zebrafish. Six other pipefish gene losses are inferred to be convergent losses with respect to some members of Percomorpha because other species that are not pipefish sister lineages have also lost these genes. hox cluster-associated evenskipped gene eve1 (a member of the evx paralogy group) is missing in pipefish, a loss that has not been reported in other teleosts. Though percomorphs likely share the loss of the hoxcb cluster, comparison via conserved synteny with zebrafish shows that the orthologous region is on pipefish LG 20