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Disorders of sexual development in poultry
1Murdoch Childrens Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia.
Abstract:
Sex in birds is determined genetically, as in mammals. However, in birds, female is the heterogametic sex (ZW), while the male is homogametic (ZZ). Although the exact mechanism of avian sex determination is still unclear, genes on one or both of the sex chromosomes must control sexual differentiation of the embryonic gonads into testes or ovaries, and eventually all other sexually dimorphic features. In this review of disorders of sexual development in poultry, we focus upon the gonads and external dimorphisms. Abnormalities of sexual development in poultry can be broadly divided into 2 types: those due to disturbances in sex hormone production by the gonads, and those due to abnormal inheritance of sex chromosomes. Recent studies on gynandromorphic chickens (half male, half female) point to the importance of genetic over hormonal factors in controlling sexual development in fowl.
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