We have done a comparative analysis of processed ribosomal protein pseudogenes in four fully sequenced mammalian genomes (human, chimpanzee, mouse and rat). To this end, we have developed an approach to identify corresponding pseudogenes in syntenic blocks. Our analysis indicates that most of the pseudogenes detected arose after the human- rodent split as a result of lineage specific retrotranspositional events. In addition, it suggests a greater amount of recent retrotransposition in the rodent lineage than in the primates.
Landmarks are genes that are found on either side of a pseudogene. We identify syntenic regions between two species by locating orthologous genes in the two species on either side of a pseudogene. The landmark files give the gene anchors around each pseudogene which we used to identify syntenic regions between two species.