Researchers have begun to home in on what makes people sociable by studying a genetic syndrome that leads people to be overly social, Live Science reports.
Williams syndrome has been traced to deletions of certain genes on chromosome 7 and researchers from the University of California, San Diego, report this week in Nature that they've developed a neurodevelopmental model of the disease using cells isolated from the baby teeth of affected children. Those cells were then reprogrammed into induced pluripotent stem cells and underwent induction into neurons.
By comparing these Williams syndrome model cells to normal cells, UCSD researchers led by Alysson Muotri found that Williams syndrome neurons had longer dendrites and more spines and synapses. In addition, they had atypical calcium oscillations and exhibited differences in network connectivity.
"Why this [enhanced connectivity] is related to sociability and not intelligence [or] memory or any other benefit is still a mystery," Muotri tells Live Science. "I speculate that this is because this seems to be restricted to a specific type of neuron related to the social aspect."
She and her team also report in their paper that they narrowed in on a single candidate gene for this cellular phenotype, as FZD9, which regulates cell division and apoptosis, was hemizygously deleted in Williams syndrome patients. Restoring FZD9 in Williams syndrome in neural progenitor cells in a certain timeframe, they add, increased their number to what's present in controls.