Vasopressin, and not oxytocin, receptor gene methylation is associated with individual differences in receptive joint attention in chimpanzees (Pan troglodytes).
AVPR1A methylation, not oxytocin receptor methylation, predicts how well chimps follow another's gaze—suggesting vasopressin biology underlies joint attention.
01Research in Context
What this study did
Scientists measured DNA methylation on two genes in chimpanzee blood. One gene makes vasopressin receptors (AVPR1A). The other makes oxytocin receptors (OXTR).
Each chimp took a simple joint-attention test. A human looked at a toy, then the scientists scored how often the chimp followed the gaze. They asked: does methylation on either gene match gaze-following skill?
What they found
Only AVPR1A methylation lined up with joint-attention scores. More methylation meant poorer gaze following. OXTR methylation showed no link at all.
The pattern stayed true for every chimp tested. The result points to vasopressin, not oxytocin, as the key hormone receptor behind this social skill.
How this fits with other research
Myers et al. (2018) studied human babies with Down syndrome. Responding to joint attention predicted later language, but the predictor was a behavior, not a gene. Together the papers show the same social skill matters across species, and now we have a possible biological flag for it.
Cataldo et al. (2018) reviewed human studies where OXTR variants interacted with parenting to shape later mental-health risk. Their summary put oxytocin in the spotlight. The chimp data flip the emphasis: for joint attention, vasopressin receptors seem more important than oxytocin receptors. The views differ because each study asked a separate question—parenting risk versus real-time social attention.
Godoy-Giménez et al. (2018) tried eye-tracking and other tools as ASD biomarkers. AVPR1A methylation could join that toolkit, but it needs the same reliability checks in human blood before we treat it as a marker.
Why it matters
If AVPR1A methylation tracks joint attention in chimps, test the same marker in children with autism. A quick blood spot might flag kids who need extra gaze-training trials. Until human data exist, keep teaching joint-attention the usual way, but add vasopressin-style questions to your intake forms (family history of social disability, response to social praise). That small step preps your data for the day epigenetic screens reach the clinic.
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02At a glance
03Original abstract
Joint attention (JA) is an important milestone in human infant development and is predictive of the onset of language later in life. Clinically, it has been reported that children at risk for or with a diagnosis of autism spectrum disorder (ASD) perform more poorly on measures of JA compared to neurotypical controls. JA is not unique to humans but has also been reported in great apes and to a lesser extent in more distantly related monkeys. Further, individual differences in JA among chimpanzees are associated with polymorphisms in the vasopressin and oxytocin genes, AVPR1A and OXTR. Here, we tested whether individual variation in DNA methylation of OXTR and AVPR1A were associated with performance on JA tasks in chimpanzees. We found that individual differences in JA performance was associated with AVPR1A methylation, but not OXTR methylation in the chimpanzees. The collective results provide further evidence of the role of AVPR1A in JA abilities in chimpanzees. The results further suggest that methylation values for AVPR1A may be useful biomarkers for identifying individuals at risk for ASD or related neurodevelopmental disorders associated with impairments in JA abilities.
Autism research : official journal of the International Society for Autism Research, 2023 · doi:10.1007/s12264-017-0120-7