Darren Gough was unwittingly showing off more than his prowess on the dance floor when he swept to success in Strictly Come Dancing. Scientists have found that good dancing is also a sign of genetic perfection.
Charles Darwin was the first to suggest that the universal human need to dance is part of an evolutionary phenomenon known as sexual selection - when individuals choose mates on the basis of some measure of physical attractiveness.
Now scientists have produced the first real evidence to show that dancing is indeed linked to physical well-being and that women in particular use performance on the dance floor as an indication of genetic superiority.
A study has found that men and women more admire the dancing ability of those members of the opposite sex who happen to have a greater degree of body symmetry - a proven measure of biological well-being - even though the symmetry won't have been obvious at the time.
Scientists believe the findings show that dance may have evolved to be so important in human culture because it is a way of allowing men and women to judge the symmetry and therefore underlying genetic fitness of potential mates.
The study, published in the journal Nature, found that women were more likely than men to make a subconscious link between dancing and physical symmetry, which fits in with an evolutionary theory about how important it is for females in particular to choose an attractive, good-quality mate.
"Dance is believed to be important in courtship of species, including humans, but nothing is known about what dance reveals about the underlying [physical or genetic] quality of the dancer," say the researchers, led by William Brown and Robert Trivers of Rutgers University, New Jersey. "Here we report that there are strong positive associations between symmetry and dancing ability, and these associations were stronger in men than in women," they say. "In addition, women rate dances by symmetrical men relatively more positively than do men, and more-symmetrical men value symmetry in women dancers more than do less-symmetrical men."
The study was based on videos made of 183 men and women in Jamaica while they danced to the same music. The videos were carefully edited to eliminate any obvious signs of symmetry - a measure of how similar are the left and right sides of the body.
The scientists had assessed symmetry using callipers to measure wrists, ankles, elbows, fingers, ears and so on. Hands were X-rayed, casts made of the upper teeth, and facial symmetry assessed from photographs.
"This information forms the foundation for all other work and is the most detailed set of bodily measurements on symmetry available for any group of human beings," the scientists said.
A second group of people was then asked to judge the dancing ability of each person in the video which enabled the scientists to distinguish those who were perceived to be good dancers from those who were judged to be poor. The scientists found that symmetrical males were judged by females to be significantly better dancers.
Professor John Manning of the University of Central Lancashire in Preston, who researches the biological basis of body symmetry, said the findings showed that dancing was used as a marker of underlying genetic fitness. "When women look at a man and judge his dancing, they are picking up on his symmetry and that picks up on his genes," he said.