An example of the map of mammalian breakpoints and ANKRD26 homologs. Cattle chromosomes are used as reference chromosomes and are respectively compared to goat RH maps, pig (S. scrofa), horse (E. caballus), dog (C. familiaris), human (H. sapiens), macaque (M. mulatta), mouse (M. musculus), and rat (R. norvegicus) in the Evolution Highyway program. Large blocks of homologous synteny and a high frequency of breakpoint reuse are presented on mammalian chromosomes. We combined of this map of mammalian breakpoints and the genomic distribution ofANKRD26 family (Additional file 8) and take examples of cattle chromosome 13 in this figure. Most members of ANKRD26 family locate on species-specific or lineage- specific rearrangement regions or centromeres (red cross), whereas a very few (blue cross) were located on HSBs. The homologous copies of ANKRD26 are spotted intensively in two neighboring breakpoint regions, where ANKRD26 locate. One likely reason for of this excessive gene duplication is that the HSB between the two neighboring breakpoints have undergone repeatedly inversion, thus ANKR26 copies accumulated.