This 2015 Virginia human study:

“Reveals how epigenetic variability in the endogenous oxytocin system impacts brain systems supporting social cognition and is an important step to better characterize relationships between genes, brain, and behavior.”

The researchers did a lot of things right:

• They studied a priori selected brain areas, followed by whole brain analyses;
• Their subjects were carefully selected
  

  “Because methylation levels have been shown to differ as a function of race, we restricted our sample to Caucasians of European descent”

  but they didn’t restrict subjects to the same gender;

• They acknowledged as a limitation:
  

  “A lack of behavioral evidence to reveal how these epigenetic and neural markers impact the overt social phenotype.”

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One thing on which I disagree with the researchers is their assessment of what needs to be done next. Their news release stated:

“When imagining the future possibilities and implications this DNA methylation and oxytocin receptor research may have, the investigators think a blood test could be developed in order to predict how an individual may behave in social situations.”

Nice idea, but the next step should be to complete the research. The next step is to develop evidence for how the oxytocin receptor gene became methylated.

The subjects had a wide range of DNA methylation at the studied gene site – from 33% to 72% methylated!

Why?

At the same gene site:

“There was a significant effect of sex such that females have a higher level of methylation than males.”

Why?

Given these significant effects, why was there no research into likely causes?

Aren’t early periods in people’s lives the most likely times when the “Epigenetic modification of the oxytocin receptor gene” that “influences the perception of anger and fear in the human brain” takes place?

Wouldn’t findings from research on the subjects’ histories potentially help other people?

http://www.pnas.org/content/112/11/3308.full “Epigenetic modification of the oxytocin receptor gene influences the perception of anger and fear in the human brain”