Definition of orthologous genomic segments. The genome sequences of species 1 and 2 are subdivided into overlapping regions, each containing two annotated genes and the intergenic DNA between them. The segments from species 1 and 2 in this example are classified into three orthologous genomic segment (OGS) groups, as indicated by coloring. Letters A-G represent genes in the Ancestral genome, some of which are retained in species 1 and 2.
ÓhÉigeartaigh et al. BMC Genomics 2011 12:377 doi:10.1186/1471-2164-12-377