Oh et al. (176) studied effects of other environmental factors on DNA methylation, using a mouse model of maternal adversity – based on a deficit in the maternal 5-HT1A receptor [reduced binding of 5-HT1A has been found in peri/postpartum depression, a condition that can represent early life adversity for the offspring (177)], which causes innate anxiety, increased stress reactivity, and impaired vocal communication in the offspring – and genome-wide DNA methylation analyses. The gene discussed is HTR1A; the disease is postpartum depression.