When these measures were then compared to family trees, "a lot of these network measures popped out as having significant heritability," Brent said. That is, the behaviors seemed to run in families.
"This is really a landmark paper," said James Fowler, a professor of medical genetics and political science at the University of California-San Diego who studies human social networks, including Facebook, but who was not part of the study. "They're showing that the positive behaviors which build social networks might be heritable, and that's consistent with what we've been seeing in human studies."
The analysis of aggression didn't reveal much heritability, but it did influence reproductive success. At either end of the aggression scale, monkeys who were the most aggressive and those who were the most passive had better reproductive success than the monkeys in the middle.
The team also collected blood samples and did some genetic analysis on two genes in the serotonin system of the monkeys. Variability in the two genes -- one that makes serotonin and one that carries it around -- was most closely associated with differences in grooming connections between the monkeys.
They chose to focus their genetic analysis on two genes in the serotonin system because there is a lot of literature on that area in humans. Serotonin, a molecule that carries signals between nerve cells, is part of the system acted on by antidepressant drugs, so it has been widely studied.
"The way that genes can affect behavior is by their influence on neural circuits," said Michael Platt, director of the Duke Institute for a Brain Sciences and the Center for Cognitive Neuroscience. "We know that neural cir
|Contact: Karl Leif Bates|