Human maternal responsiveness is a complex repertoire of infant-related behaviours and attitudes, which vary between and within mothers. Environmental and socioeconomic factors undoubtedly influence maternal care, but less is known about how genetic variation associates with maternal responsiveness. Where genetic variation has been examined in relation to mothering, the moderating effects of early life experiences in the mother have not been explored. Additionally, studies tend to focus on maternal sensitivity, neglecting to explore other dimensions of maternal responsiveness. The purpose of the present thesis was to explore genetic variation in three gene families – dopamine (DA), serotonin (5-HT), and oxytocin (OXT) – in relation to differences in maternal care in a Caucasian sample of new mothers recruited in early pregnancy from Hamilton, Ontario (N=187). Furthermore, interactions between early experiences in the mothers’ lives and their genetic polymorphic variants were examined. Early experience was a combined measure of the Parental Bonding Instrument and the Childhood Trauma Questionnaire. Maternal behaviour during mother-infant interaction was assessed at 6 months postpartum and derived from a video-recorded 30-minute mother-infant interaction. The behavioural outcomes of interest maternal sensitivity (assessed using the Ainsworth Maternal Care Scales) and maternal behaviors (vocalizing, orienting away from infant, instrumental caregiving). We also assessed maternal attitudes about parenting the infant at 6 months postpartum. Multiple polymorphisms on DA receptors D1 (rs686, rs4532, rs265981, rs265976, rs5326) and D2 (rs6277, rs1799732, rs1799978, rs1800497) associated with maternal vocalizing and orienting away from the infant, respectively. The OXT polymorphisms rs2740210 and rs4813627 associated with infant-directed vocalizing. A major polymorphism on the 5-HT transporter (5HTTLPR and a related rs25531 polymorphism) associated significantly with maternal sensitivity. There were gene-environment interactions between this 5-HT polymorphism and early adversity in association with maternal orienting away and maternal attitudes. Gene-environment interactions were also found between the OXT polymorphisms rs2740210 and rs4813627 and instrumental care of the infant. These results suggest that variations in genes encoding major brain neurotransmitters and neurohormones are related to observed maternal behaviour and self-reported maternal attitudes. These results showcase the importance of exploring multiple dimensions of complex behavioural phenotypes like mothering.
| Identifer | oai:union.ndltd.org:TORONTO/oai:tspace.library.utoronto.ca:1807/34809 |
| Date | 18 December 2012 |
| Creators | Mileva, Viara |
| Contributors | Fleming, Alison S., Sokolowski, Marla B. |
| Source Sets | University of Toronto |
| Language | en_ca |
| Detected Language | English |
| Type | Thesis |
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