Mouse and rat genomic sequences permit us to obtain a global view of evolutionary rearrangements that have occurred between the two species
and to define hallmarks that might underlie these events. We present a comparative study of the sequence assemblies of mouse and rat genomes
and report an enrichment of rodent-specific segmental duplications in regions where synteny is not preserved. We show that segmental
duplications present higher rates of molecular evolution and that genes in rearranged regions have evolved faster than those located elsewhere.
Previous studies have shown that synteny breakpoints between the mouse and the human genomes are enriched in human segmental duplications,
suggesting a causative connection between such structures and evolutionary rearrangements. Our work provides further evidence to support the
role of segmental duplications in chromosomal rearrangements in the evolution of the architecture of mammalian chromosomes and in the
speciation processes that separate the mouse and the rat.