tissue. Likewise, because OXTR methylation is likely correlated with other methylation changes across the genome, it will be important to examine changes at OXTR in the context of these broader patterns in future research. Further, some researchers have found a slightly different factor structure when examining OXTR methylation, or found associations at birth or early childhood focusing on other genomic regions (e.g., exon 2, Cecil, et al., 2015; promoter, Dadds et al., 2014). Similarly, the treatment of variation at 5-HTTLPR may have been overly simplified in the current study given the potential impact of other genetic elements that can introduce variability (e.g., the A to G substitution at rs25531 for “Long” allele carriers), leading to a large number of potential allelic variants for SLC6A4 and adding potential noise to examination of effects attributable to the “s” allele at 5-HTTLPR (Nakamura, et al., 2000). Future research with much larger samples will be required to tease out the likely nuanced effects attributable to these genetic variants and a focus on alternative genomic regions.
