Your sense of humour has nothing to do with your genes, and everything to do with your upbringing say UK biologists. Most personality traits such as being introverted or extroverted are believed to be at least partly genetically determined - so researchers presumed the same applied to our sense of humour.
The team asked 71 pairs of identical twins and 56 pairs of fraternal twins, to go into separate rooms and rate five cartoons on a scale of 0 to 10. A zero deemed the cartoon "a waste of paper", while 10 meant "one of the funniest cartoons you have ever seen".
Identical twins, who have exactly the same genes were no more likely to agree on this than fraternal twins who share only half of their genes on average, like ordinary siblings - suggesting a shared environment was responsible for making brothers and sisters laugh at the same things.
"It's a surprise because most personality traits have genetic components," says Spector. "This implies that there's a lot of cultural influence on humour.""This is interesting because twin studies of personality traits almost always show genetic effects," agrees Robert Plomin, a behavioural geneticist at the Institute of Psychiatry in London, adding a larger study would be necessary to confirm these findings.