Comparing multiple related genomes can help to improve their structural annotation. The accuracy and consistency of the predicted exon-intron structures of the protein coding genes can be higher when considering all genomes at once rather than annotating one genome at a time.The comparative gene prediction algorithm of AUGUSTUS performs such a multi-genome annotation. A multiple alignment of genomes is used to exploit evolutionary clues to conservation and negative selection. Further, AUGUSTUS exploits the fact that orthologous genes typically have congruent exon-intron structures. Comparative AUGUSTUS simultaneously predicts the genes in all input genomes. In this chapter we walk the reader through a small example from eight vertebrate species, including the construction of an alignment of the input genomes and how to integrate RNA-Seq evidence from multiple species for gene finding.
