Humor Gene

A study at the Twin Research and Genetic Epidemiology Unit of St. Thomas’s Hospital in London presented 127 pairs of identical and fraternal twins with an assortment of “Far Side” cartoons and found that identical twins liked the same cartoons no more often than fraternal twins did. Identical genes did not produce identical senses of humor. On the other hand, all the siblings did generally agree on what was funny, implying that their shared environments shaped their comic sensibilities.
http://www.nytimes.com/2009/11/29/magazine/29Elliott-t.html