SNRPN and Zinc deficiency: Vitamins B: - Biotin deficiency is associated with a decrease in biotinylated histones and an increase in fertility rates (81) - Vitamin B mixture increases methylation level of H3K27 (82)Folate: - Reduced DNA methylation variance in KCNQ1OT1, SNRPN and PEG1 (84) - increased global DNA methylation levels in both embryonic and placental tissues (84)Zinc deficiency is associated with decreased histone H3K4 and global DNA methylation in oocytes (87)