Upon manual inspection of the gene

Upon manual inspection of the gene expansion results, we
found several duplicates of note. For instance, proliferating cell
nuclear antigen (PCNA) is duplicated in bowhead whales with
one copy harboring four lineage-specific residue changes (Figure
3B). Based on our RNA-seq data mapped to the genome
(see Experimental Procedures and full results in Supplemental
Folder 1), both PCNA copies are expressed in bowhead whale
muscle, kidney, retina, and testis. By mapping the lineagespecific
residues onto the structure of PCNA in complex with