The ALDH3 genes show the most variation in gene number of any ALDH family among the organisms studied. ALDH3A1 is missing from birds and fish but is present in every mammalian genome analysed in this study. The zebra finch has a duplicate ALDH3A2 (ALDH3A3) entry which encodes a full-length peptide that shares 84.1 per cent identity with the parent protein. Four ALDH3A2 homologues were identified within the zebrafish genome. The aldh3a2.1 is considered the parent gene. The aldh3a2.2 and aldh3a2.3 full-length gene products, respectively, share 64.9 per cent and 70.9 per cent sequence identity with that of Aldh3a2.1 and 64.9 per cent identity with each other. Zebrafish aldh3a2p1 represents a partial gene duplication; the resulting 169-AA peptide would most likely undergo proteolytic degradation if translated.
