Connectivity-based syntenic blocks can identify protein-coding genes across species.

(A) The connectivity-based block 442 included orthology-based block 213 (green) and 214 (blue) along with the intermediate region and an upstream flanking region (both grey). (B) The protein-protein interaction (PPI) network for block 442. The nodes are colored by the location of the protein-coding gene. Purple: unique for block 442, green: also in orthology-based block 213, blue: also in orthology-based block 214, and grey: in another connectivity-based block on the same chromosome. Black edges represent PPIs unique for block 442. PROL1 and MUC7 make the small network that identified block 442 as syntenic. Their genomic location in the intermediate stretch could include orthologous genes in the compared species despite not yet being identified. (C) Protein alignments of the human PROL1 and MUC7 against the translated intermediate block region in pig, dog and mouse. These alignments revealed sequence conservation.