The research was performed on 49 female monkeys. They were
pulled out of their families and forced into new groups that the
researchers created. Why females? Male monkeys tend to switch
families (they have a looser concept of what a family is than we
do) while the female monkeys almost never do. Researchers were
quick to point out the parallels with impoverished humans, who
tend to have worse health than those better off. The scientists
then looked at the monkey’s DNA. What they found was that being
in a position of dominance resulted in more ‘methyl groups’,
which genes turn on and off. Jenny Tung, one of the lead
researchers on the project and the lead author, told Gizmodo in
an email: Because all the study subjects had been middle ranking
in their original groups, we can infer that it was the new
dominance ranks they adopted that explained rank-related gene
expression. We think that social stress explains these effects
because a great deal of research has linked lower rank to
increased social stress in cap