DMRT1gene disruption alone induces incomplete gonad feminization in chicken

Abstract Compared with the well‐described XY sex determination system in mammals, the avian ZW sex determination system is poorly understood. Knockdown and overexpression studies identified doublesex and mab‐3‐related transcription factor 1 ( DMRT1 ) as the testis‐determining gene in chicken. However, the detailed effects of DMRT1 gene disruption from embryonic to adult development are not clear. Herein, we have generated DMRT1 ‐disrupted chickens using the clustered regularly interspaced short palindromic repeats‐associated protein 9 system, followed by an analysis of physiological, hormonal, and molecular changes in the genome‐modified chickens. In the early stages of male chicken development, disruption of DMRT1 induced gonad feminization with extensive physiological and molecular changes; however, functional feminine reproductivity could not be implemented with disturbed hormone synthesis. Subsequent RNA‐sequencing analysis of the DMRT1 ‐disrupted chicken gonads revealed gene networks, including several novel genes linearly and non‐linearly associated with DMRT1 , which are involved in gonad feminization. By comparing the gonads of wild type with the genome‐modified chickens, a set of genes were identified that is involved in the ZW sex determination system independent of DMRT1 . Our results extend beyond the Z‐dosage hypothesis to provide further information about the avian ZW sex determination system and epigenetic effects of gonad feminization.