OMIA:002531-74940 : XY sex reversal, sdY-related in Oncorhynchus tshawytscha (Chinook salmon)

Categories: Reproductive system phene

Mendelian trait/disorder: yes

Considered a defect: yes

Key variant known: yes

Year key variant first reported: 2022

Cross-species summary: This is a type of XY difference of sexual development (XY DSD) due to variants in the sdY gene. Renamed from XY DSD (Disorder of Sexual Development), sdY-related. [24/09/2023]

Molecular basis: Bertho et al. (2022) "amplified and sequenced sdY gene between exons 2 and 3 of XY Chinook salmon females and found that they have a missense mutation in the third exon of the sdY gene that produces a single amino acid change (I183N) in a highly conserved position of the SdY protein, while males have the wild-type copy of SdY. The mutation modifies the 3-dimensional (3D) structure. The mutant SdY I183N protein is less stable than the wild-type SdY and is affected in its ability to interact with its protein partner, Foxl2 . . . . This failure in turn leads to the inability to repress the cyp19a1a promoter and thereby to suppress female development. Altogether our results suggest that the sdY-N183 copy in XY Chinook salmon females is inactive and cannot block the female pathway in the same way as the wild-type sdY gene. Our results provide an explanation for the existence of naturally occurring XY Chinook salmon females and support the role of sdY as the master male sex-determining gene of Chinook salmon."

Prevalence: Bertho et al. (2022): "The incidence of these XY females varies between 20% and 38% in Central Valley rivers while ranging between 0% and 14% under hatchery conditions . . . . In addition, independent surveys found proportions of wild-caught XY females ranging from 12% . . . up to 84%".

Associated gene:

Symbol Description Species Chr Location OMIA gene details page Other Links
sdY Oncorhynchus tshawytscha - no genomic information (-..-) sdY Ensembl


By default, variants are sorted chronologically by year of publication, to provide a historical perspective. Readers can re-sort on any column by clicking on the column header. Click it again to sort in a descending order. To create a multiple-field sort, hold down Shift while clicking on the second, third etc relevant column headers.

WARNING! Inclusion of a variant in this table does not automatically mean that it should be used for DNA testing. Anyone contemplating the use of any of these variants for DNA testing should examine critically the relevant evidence (especially in breeds other than the breed in which the variant was first described). If it is decided to proceed, the location and orientation of the variant sequence should be checked very carefully.

Since October 2021, OMIA includes a semiautomated lift-over pipeline to facilitate updates of genomic positions to a recent reference genome position. These changes to genomic positions are not always reflected in the ‘acknowledgements’ or ‘verbal description’ fields in this table.

OMIA Variant ID Breed(s) Variant Phenotype Gene Allele Type of Variant Source of Genetic Variant Reference Sequence Chr. g. or m. c. or n. p. Verbal Description EVA ID Year Published PubMed ID(s) Acknowledgements
1427 XY female sdY missense Naturally occurring variant p.(I183N) 2022 35100376

Cite this entry

Nicholas, F. W., Tammen, I., & Sydney Informatics Hub. (2022). OMIA:002531-74940: Online Mendelian Inheritance in Animals (OMIA) [dataset].


2022 Bertho, S., Herpin, A., Jouanno, E., Yano, A., Bobe, J., Parrinello, H., Journot, L., Guyomard, R., Muller, T., Swanson, P., McKinney, G., Williamson, K., Meek, M., Schartl, M., Guiguen, Y. :
A nonfunctional copy of the salmonid sex-determining gene (sdY) is responsible for the "apparent" XY females in Chinook salmon, Oncorhynchus tshawytscha. G3 (Bethesda) 12:jkab451, 2022. Pubmed reference: 35100376. DOI: 10.1093/g3journal/jkab451.

Edit History

  • Created by Frank Nicholas on 21 Feb 2022
  • Changed by Frank Nicholas on 21 Feb 2022