Zhang et al. generated a congenic line of the C57BL/6J mouse strain with the capacity of melatonin synthesis via introducing functional alleles of Aanat and Asmt genes from the melatonin-proficient CBA/CaJ mouse strain to B616, and genetic deletion of MT1 melatonin receptor caused depressive and anxiety-like behaviors in male and female C57BL/6 mice17. The gene discussed is ASMT; the disease is Anxiety.