Dmrtb1, also known as DMRT6, belongs to the DMRT family. It plays critical functions in sex determination/differentiation, gonadal development, and functional maintenance, and is involved in the transition between mitosis and meiosis in germ cells [1,2,6]. It may also have a role in the evolution of tetrapod testes size [3].

In the large yellow croaker (Larimichthys crocea), Lcdmrtb1 (a dmrtb1 homolog) was highly expressed in the testis. RNA interference of Lcdmrtb1 in testis cells led to decreased expression of related genes like Lcdmrt1, sox9a/b, and amh, altered cell morphology, reduced growth rate, disappearance of spermatogonia, and reduction of Sertoli cells [1]. In mice, a null mutation in Dmrt6 disrupted spermatogonial differentiation in C57BL/6J strain, causing inappropriate expression of differentiation and meiotic initiation factors and apoptosis of late spermatogonia. In 129Sv background mice, Dmrt6 mutant germ cells had defects in meiotic chromosome pairing and mainly arrested in mid-pachynema [6]. Deletion of an evolutionarily conserved topologically associated domain boundary near Dmrtb1 in mice led to significant changes in testis gene expression, abnormal histology, reduced efficiency of meiosis and spermatogenesis, and decreased daily sperm production [4,5].

In conclusion, Dmrtb1 is crucial for testicular development and the transition between mitosis and meiosis in germ cells. Studies using gene-knockout mouse models have revealed its role in spermatogenesis, and its disruption can lead to abnormal testis function, highlighting its importance in male fertility-related research [1,4,5,6].