CDKN1C and Anxiety: A comparable phenotype, interpreted as social instability, is present in the Cdkn1cBACx1 mouse model, which overexpresses imprinted cyclin dependent kinase inhibitor 1c (Cdkn1c).22 Social instability has adverse effects on individual fitness including anxiety, stress and reduced breeding rates.26, 27, 28Cdkn1cBACx1 mice do not occupy more dominant ranks than their WT cage‐mates on any individual measure of within‐cage social hierarchy.