The unique pentraxin-carbonic anhydrase protein regulates the ability of fish to swim
(PHYSorg.com Biology)

A study carried out at the University of Tampere has shown that carbonic anhydrase VI (CA VI) is present in some species as a combination of two proteins. According to current data, this `fusion protein,` called pentraxin-carbonic anhydrase, has disappeared from the genome of almost all mammals through evolution.