Sordl is a paralog of Sord1 and Sord2 and is specifically expressed in testis. It is not clear if Sordl is enzymatically active as the NAD(+) binding residues are not conserved. As there is no functional information, Sordl is not included in the gene list. Ar3, Ar4, Ar5, Ar6, Ar7 and ARY are paralogs of Ar1 and Ar2. Ar7 and ARY are specifically expressed in testis. As there is no functional information, Ar3, Ar4, Ar5, Ar6, Ar7 and ARY are not included in the gene list.