In the context of histone modifications, Erica Y. Shen et al. [41] showed that the deletion of a histone methyltransferase (Kmt2a/Mll1) led to a defective spike in medium spiny neurons and induced anxiety behaviors in mice, as was demonstrated in an elevated plus maze, light/dark box, and open-field tests (p < 0.05). Here, PRDM9 is linked to Anxiety.