Table 1.

Evidence for effects of genomic inprinting on the oxytocinergic system and infant sucking. This table presents all of the data on imprinted genes in this context, and there are no findings that contravene expectations from theory

Imprinted gene, expression pattern	Evidence regarding oxytocin, infant feeding	References
PEG3 (paternally- expressed gene 3)	Knockout associated with reduced sucking in pups, large reduction in oxytocinergic neurons in adult females, reduced nursing by mothers, in mice	Li et al. (1999), Curley et al. (2004) and Champagne et al. (2009)
NDN (necdin), paternally-expressed	Knockout associated with large reduction in oxytocinergic neurons in hypothalamus, in mice	Muscatelli et al. (2000)
MAGEL2 (MAGE-like 2), paternally-expressed	Knockouts show poor infant sucking, large reduction in oxytocinergic neurons in hypothalamus, impaired oxytocin secretion; knockouts rescued by single postnatal oxytocin injection, in mice	Schaller et al. (2010) ans Schaaf et al. (2013)
GNASxl locus (Guanine Nucleotide-Binding Protein G(S) Subunit Alpha Isoforms XLas, paternally-expressed	Knockouts show reduced sucking in mice, deletions involve reduced sucking in humans	Plagge et al. (2004), Geneviève et al. (2005)
DLK1 (Delta-like 1 Homolog), paternally-expressed	Highly, selectively expressed in oxytocinergic neurons of hypothalamus after birth, in mice, and affects post-natal growth; locus appears to underlie feeding reductions in human maternal uniparental disomy of chromosome 14	Buiting et al. (2008), Temple et al. (2009) and Villanueva et al. (2012)
GTF2I (General Transcription Factor IIi), maternal bias in expression	Williams syndrome involves deletion of one copy, increased levels of serum oxytocin, increased social behavior; duplications involve separation anxiety in both mice and humans; unknown if gene affects oxytocinergic system	Collette et al. (2009), Dai et al. (2012) and Mervis et al. (2012)
PEG1 (MEST) Paternally-expressed gene 1	Knockout females show reduced, abnormal maternal behavior, comparable to that of PEG3 knockouts; effects on feeding, oxytocinergic system, unstudied	Lefebvre et al. (1998)