Wallis, MaryDelbridge, MargaretPask, Andrew JAlsop, AmberGrutzner, FrankO'Brien, Patricia C MRens, WillemFerguson-Smith, Malcolm AGraves, Jennifer2015-12-101424-8581http://hdl.handle.net/1885/57113In the absence of an SRY orthologue the platypus sex determining gene is unknown, so genes in the human testis determining pathway are of particular interest as candidates. SOX9 is an attractive choice because SOX9 deletions cause male-to-female sex reversal in humans and mice, and SOX9 duplications cause female-to-male sex reversal. We have localized platypus SOX9, as well as the related SOX10, to platypus chromosomes 15 and 10, respectively, the first assignments to these platypus chromosomes, and the first comparative mapping markers from human chromosomes 17 and 22. The autosomal localization of platypus SOX9 in this study contradicts the hypothesis that SOX9 acts as the sex determining switch in platypus.Keywords: transcription factor Sox9; article; chromosome 10; chromosome 15; chromosome 17; chromosome 21; controlled study; gene deletion; gene duplication; gene function; gene location; gene mapping; male; nonhuman; nucleotide sequence; platypus; priority journal;200710.1159/0000981922015-12-09