Research ArticlePSYCHOLOGY

Epigenetic dynamics in infancy and the impact of maternal engagement

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Science Advances  16 Oct 2019:
Vol. 5, no. 10, eaay0680
DOI: 10.1126/sciadv.aay0680
  • Fig. 1 Infant OXTRm changes across infancy.

    Plotted are the frequency distributions of OXTRm change scores for mothers (magenta) and infants (orange). Change scores were calculated by subtracting methylation levels at the 5-month visit from methylation levels at the 18-month visit. Scores above zero indicate an increase in OXTRm over time, while scores below zero represent a decrease. Infants display nearly double the amount of change (range = 17.60; P = 0.04) than that displayed in mothers (range = 9.70; P = 0.61).

  • Fig. 2 Maternal engagement predicts a reduction in infant OXTRm over time.

    (A) Full model. An actor-partner interdependence model was used to test the effect of maternal and infant behavioral engagement on maternal and infant OXTRm change. To separate meaningful variation from measurement error, we created latent variables for the methylation data derived from values from three technical replicates (labeled Rep. 1 to Rep. 3 in the figure) (RMSEA = 0.0, CFI = 1, and TLI = 1). Single-headed linear arrows are labeled with standardized β coefficients, indicating directionality. Covariances are represented by double-headed linear arrows and indicate no directionality. Double-headed, curved error paths pointing to each respective variable represent the residual variance within each variable not accounted for by the model paths. (B) Reduced model. Path removal was used to determine the driving paths of the model (RMSEA = 0.0, CFI = 1, and TLI = 1). This model does not significantly differ from the full model (P = 0.516). Even when taking into account the positive covariance between infant and maternal engagement at 5 months, only maternal engagement predicts infant OXTRm change (reduction) from 5 to 18 months (β = −0.30).

  • Fig. 3 Maternal engagement fine-tunes infant OXTRm from 5 to 18 months, which in turn associates with overt infant temperament at 18 months.

    (A) Plotted is the association between maternal engagement at 5 months (x axis) and infant OXTRm change from 5 to 18 months (y axis). The slope of the regression line is the predicted β value derived from the actor-partner interdependence model (β = −0.30, P = 0.009). Note that engagement and methylation scores were standardized for this analysis (Z score transformed). (B) Scatterplot visualizing the association between infant OXTRm at 18 months and temperamental discomfort (log transformed) as measured by the Early Childhood Behavior Questionnaire (ECBQ) (17), r(80) = 0.293, P = 0.008. The discomfort subscale of the ECBQ measures the amount of negative affect one’s infant feels toward certain sensory qualities of stimulation, such as complexity, rate, and intensity of sounds, light, and textures. Shaded orange bar represents the 95% confidence interval.

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/5/10/eaay0680/DC1

    Supplementary Results

    Fig. S1. Regulatory CpG site −924 in the promoter region of human OXTR is directly conserved in prairie vole Oxtr.

    Fig. S2. Infant and maternal OXTRm from 5 to 18 months.

    Fig. S3. Infant and maternal OXTRm is correlated at both visits.

    Fig. S4. The variance in infant OXTRm increases from 5 to 18 months.

    Fig. S5. Maternal OXTRm does not change from 5 to 18 months.

    Fig. S6. Exploratory latent difference score model.

    Table S1. Infant and maternal OXTR methylation at 5- and 18-month visits.

    Table S2. Table displaying Pearson’s r coefficients for each OXTR methylation measurement and demographic variable.

    Table S3. Mother-reported questionnaire descriptives and demographics.

    Table S4. Descriptives for each subscale of the free-play analysis coding scheme.

  • Supplementary Materials

    This PDF file includes:

    • Supplementary Results
    • Fig. S1. Regulatory CpG site −924 in the promoter region of human OXTR is directly conserved in prairie vole Oxtr.
    • Fig. S2. Infant and maternal OXTRm from 5 to 18 months.
    • Fig. S3. Infant and maternal OXTRm is correlated at both visits.
    • Fig. S4. The variance in infant OXTRm increases from 5 to 18 months.
    • Fig. S5. Maternal OXTRm does not change from 5 to 18 months.
    • Fig. S6. Exploratory latent difference score model.
    • Table S1. Infant and maternal OXTR methylation at 5- and 18-month visits.
    • Table S2. Table displaying Pearson’s r coefficients for each OXTR methylation measurement and demographic variable.
    • Table S3. Mother-reported questionnaire descriptives and demographics.
    • Table S4. Descriptives for each subscale of the free-play analysis coding scheme.

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