Recovering genome rearrangements in the mammalian phylogeny.

The analysis of genome rearrangements provides a global view on the evolution of a set of related species. We present a new algorithm called EMRAE (efficient method to recover ancestral events) to reliably predict a wide-range of rearrangement events in the ancestry of a group of species. Using simulated data sets, we show that EMRAE achieves comparable sensitivity but significantly higher specificity when predicting evolutionary events relative to other tools to study genome rearrangements. We apply our approach to the synteny blocks of six mammalian genomes (human, chimpanzee, rhesus macaque, mouse, rat, and dog) and predict 1109 rearrangement events, including 831 inversions, 15 translocations, 237 transpositions, and 26 fusions/fissions. Studying the sequence features at the breakpoints of the primate rearrangement events, we demonstrate that they are not only enriched in segmental duplications (SDs), but that the enrichment of matching pairs of SDs is even stronger within the pairs of breakpoints associated with recovered events. We also show that pairs of L1 repeats are frequently associated with ancestral inversions across all studied lineages. Together, this substantiates the model that regions of high sequence identity have been associated with rearrangement events throughout the mammalian phylogeny.