Polledness intersex syndrome in goatsmolecular and histological aspects

Abstract

Polledness intersex syndrome (PIS) is a phenomenon associated with 2 distinct conditions occurring in goats, namelypolledness and intersexuality. The first is a trait exhibiting complete dominance, whereas the latter is recessive. The extreme case ofintersexualism is complete sex reversal, which is observed only in females (60,XX). The trait PIS is inherited in a recessive manner andcaused by deletion of 11.7 kbp DNA on chromosome 1q43. Female goats with PIS exhibit a broad range of developmental abnormalitiesof the sexual system, from only subtle changes to complete sex reversal. The phenotypic diversity in goats with PIS is most likely an efectof complexity of the sexual diferentiation process, in which the gene-dosage efect may potentially play a crucial role, in addition to thenumerous molecular factors regulating the developmental pathway. Te occurrence may explain diferent degrees of masculinization.Nevertheless, the sex reversal phenomenon appearing in female goats (60,XX) with PIS is not considered a serious problem in breedingprograms because properly planned selection of individuals for reproduction can allow for complete exclusion of risk of occurrenceof this syndrome in ofspring. On the other hand, female goats with PIS are still one of the most suitable animal models for studyingcomplex processes of determination and diferentiation of sex in mammals.