Inactivation of the Anti-Müllerian Hormone Receptor Type 2 (amhrII) Gene in Northern Pike (Esox lucius) Results in Male-To-Female Sex Reversal.

BACKGROUND: The anti-müllerian hormone (Amh) pathway is crucial for sexual development in teleosts. A male-specific duplicate of anti-müllerian hormone (amhby) was previously identified as the northern pike (Esox lucius) master sex determination gene. However, the role of its putative cognate receptor, i.e., the anti-müllerian hormone receptor type 2 (amhrII) was unclear in this species. OBJECTIVE: Here, we investigated the role of amhrII during sexual development of northern pike. METHOD: We generated stable mutants with deletions in exon 9 of amhrII, inactivating the AmhrII protein using a CRISPR-Cas9-mediated gene knockout strategy. RESULT: The inactivation of amhrII in northern pike results in a high level of male-to-female sex reversal. CONCLUSION: This result demonstrates that amhrII is necessary for male sexual development in northern pike and supports the idea that AmhrII is a conserved regulator of the teleosts sex differentiation network.