Whether you're the life of the party -- or a wallflower -- your party-personality may partly depend on your genetic make-up.
Researchers at the University of California, San Diego analyzed the social networks of more than a thousand twins.
Some were identical - meaning they had the exact same genes - and others were fraternal. Social circles were much more similar among the identical twins than the fraternal.
While the research could some day help to pinpoint personality genes, researchers say this doesn't mean they'll be able to change someone's personality by simply switching a gene on or off.
That's because personality is also heavily influenced by how you're raised.