Abstract The vertebrate globin gene repertoire consists of seven members that differ in terms of structure, function and phyletic distribution.While hemoglobin, myoglobin, cytoglobin, and neuroglobin are present in almost all gnathostomes examined so far, other globin genes, like monster scooter batteries globin X, are much more restricted in their phyletic distribution.Till today, globin X has only been found in teleost fish and Xenopus.
Here, we report that globin X is also present in the genomes of the sea lamprey, ghost shark and reptiles.Moreover, the identification of orthologs of globin X oswald the octopus stuffed animal in crustacean, insects, platyhelminthes, and hemichordates confirms its ancient origin.